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  • Articles  (143)
  • nitrogen  (89)
  • biological control  (55)
  • Animals
  • Chemical Engineering
  • 1985-1989  (143)
  • Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition  (133)
  • Geosciences  (10)
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  • Articles  (143)
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  • 1
    Electronic Resource
    Electronic Resource
    Potential for the biological control ofLeptinotarsa decemlineata [Col.: Chrysomelidae] by the egg parasite,Edovum puttleri [Hym.: Eulophidae] in Maryland, 1981–84 (1989)
    Springer
    BioControl 34 (1989), S. 135-141 
    Details
    ISSN: 1573-8248
    Keywords: Edovum puttleri ; biological control ; Colorado potato beetle ; Leptinotarsa decemlineata ; Edovum puttleri ; lutte biologique ; doryphore ; Leptinotarsa decemlineata
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé L'efficacité potentielle d'Edovum puttleri Grissell, parasite oophage exotique deLeptinotarsa decemlineata a été examinée dans des parcelles expérimentales de pomme de terre. Le parasite n'hiverne pas au Maryland, mais par un lâcher inoculatif annuel il parasite les pontes du Doryphore durant la saison. Cinquante p. 100 environ des pontes récoltées étaient parasitées et le maximum de parasitisme parE. puttleri s'observait dans les pontes dues aux adultes de la première génération.E. puttleri se reproduit et se maintient dans les parcelles de pomme de terre durant 15 semaines. L'échantillonnage au hasard des pontes du Doryphore pour évaluer le parasitisme dans les champs est décrit.
    Notes: Abstract The biological control potential ofEdovum puttleri Grissell, an exotic egg parasite ofLeptinotarsa decemlineata (Say), was examined in experimental potato plots. The parasite does not overwinter in Maryland, but through annual inoculative releases it consistently parasitized Colorado potato beetle (CPB) egg masses throughout the season. Approximately 50% of all egg masses collected were parasitized and maximum parasitism byE. puttleri occurred in egg masses produced by first generation adults.Edovum puttleri reproduced and maintained itself in potato plots for 15 weeks. The random sampling of CPB egg masses to evaluate the parasite in the field is described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372597
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  • 2
    Electronic Resource
    Electronic Resource
    Introduction and establishment ofTrioxys pallidus [Hym.: Aphidiidae] in Oregon, U.S.A. for control of filbert aphidMyzocallis coryli [Hom.: Aphididae] (1989)
    Springer
    BioControl 34 (1989), S. 153-163 
    Details
    ISSN: 1573-8248
    Keywords: Trioxys pallidus ; Myzocallis coryli ; hazelnuts ; biological control ; aphids ; Trioxys pallidus ; Myzocallis coryli ; noisetier ; lutte biologique ; pucerons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Les parasitoïdes du puceron du noisetier,Myzocallis coryli (Goetze) ont été recherchés dans des parcelles de noisetier en Espagne, en France, et en Italie. Un même biotype deTrioxys pallidus Haliday a été observé parasitant ce puceron dans toute l'Europe Occidentale. Cet insecte a été importé, passé en quarantaine, élevé en masse et lâché sur les noisetiers de l'Oregon. Ce parasite attaque avec succès les populations du puceron du noisetier de l'Oregon, et il effectue son développement complet sur cet hôte. Un élevage continu deT. pallidus a été maintenu en serre pendant plus de 50 générations et environ 30 000 adultes ont été lâchés dans la partie Ouest de l'Oregon. Les conditions de survie hivernale ont été étudiées dans au moins 12 situations différentes. Dans 3 exploitations commerciales, les parasitoïdes se sont montrés capables d'abaisser de 33 à 48% les populations maximales du puceron.
    Notes: Abstract Hazelnut orchards in Spain, France, and Italy were searched for parasitoids of the filbert aphid,Myzocallis coryli (Goetze). A biotype ofTrioxys pallidus Haliday was found to parasitize the aphid throughout western Europe. Wasps were imported, quarantined, mass-reared, and released in Oregon orchards. The wasp successfully attacked and completed its development on Oregon populations of the filbert aphid. A greenhouse culture of the parasitoid was maintained continuously for over 50 generations, and approximately 30,000 adult wasps were released in western Oregon. Overwintering survival has been documented in at least 12 different locations. In 3 commercial hazelnut orchards, the parasitoids proved capable of reducing aphid population peaks by 33–48%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372664
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  • 3
    Electronic Resource
    Electronic Resource
    Host-specificity and virus-vector potential ofAphis chloris [Hemiptera: Aphididae], a biological control agent for St John's wort in Australia (1989)
    Springer
    BioControl 34 (1989), S. 247-264 
    Details
    ISSN: 1573-8248
    Keywords: Aphis chloris ; Hypericum perforatum ; biological control ; host-specificity ; virus transmission ; Aphis chloris ; Hypericum perforatum ; lutte biologique ; spécificité pour l'hôte ; transmission du virus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Les tests réalisés au laboratoire montrent qu'A. chloris est spécifique des plantes du genreHypericum. Provoquant d'importants dégats sur son hôte principal,Hypericum perforatum, ce puceron peut contribuer efficacement au contrôle de cette mauvaise herbe. Les autres espèces d'Hypericum sont nettement moins attaquées et donc peu menacées par son introduction. Aphis chloris présente un niveau de discrimination élevé lors du choix de sa plante hôte; il ne transmet pas de virus persistants entre plantes non-hôtes. Bien que capable, au laboratoire, de transmettre des virus non-persistants, il ne contribuerait que très marginalement, en cas d'introduction aux risques de propagation de virus posés par l'ensemble des aphides australiens. Son lâcher ne devrait pas impliquer de modifications dans les techniques de lutte mises en œuvre pour limiter la transmission des virus entre plantes. Ces résultats permettent d'envisager sans risque l'introduction d'Aphis chloris en Australie dans le cadre de la lutte biologique contreHypericum perforatum.
    Notes: Abstract Under laboratory conditionsAphis chloris Koch has been demonstrated to be specific to plants belonging to the genusHypericum. It can effect severe damage to its principal host,H. perforatum L., and shows good potential for contributing to the control of this noxious weed. Other species ofHypericum are less favoured hosts ofA. chloris and would not be endangered by it. A. chloris shows a high level of host-discrimination and does not transmit persistent viruses between non-host plants. Whereas in the laboratory it is capable of transmitting non-persistent viruses, it would contribute only marginally to the risk of virus transfer posed by the Australian aphid fauna as a whole, and its release would not necessitate changes to existing control practices, where these are required to reduce plant virus transmission. As a consequence,A. chloris is considered safe for release againstH. perforatum in Australia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372674
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  • 4
    Electronic Resource
    Electronic Resource
    Biological studies including population growth parameters of the predatory miteAmblyseius barkeri [Acarina.: Phytoseiidae] at 25°C in the laboratory (1989)
    Springer
    BioControl 34 (1989), S. 275-287 
    Details
    ISSN: 1573-8248
    Keywords: Amblyseius barkeri ; Phytoseiidae ; Thrips ; population growth ; biological control ; Tetranychus urticae ; Polyphagotarsonemus latus ; pollen ; Amblyseius barkeri ; Phytoseiidae ; thrips ; accroissement des populations ; lutte biologique ; Tetranychus urticae ; Polyphagotarsonemus latus ; pollen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Les durées moyennes de développement des œufs, des larves et des nymphes d'Amblyseius barkeri (Hughes) nourris deThrips tabaci (Lind) ont été respectivement 2,2, 0,8 et 3,2 jours, avec des mortalités respectives de 1,0, 1,0 et 3,1%. Les ♀♀ ont constitué 63% de la population, et pour obtenir la fertilité optimum, plusieurs accouplements ont été nécessaires. La période d'oviposition était de 20,3 jours, et l'oviposition moyenne a été de 2,3 œufs par jour. L'accroissement réel était de 0,22 par jour. La durée de vie attendue était de 29,6 jours pour les ♀♀ et de 27,4 jours pour les ♂♂. LesA. barkeri ♂♂ ainsi que les ♀♀ ont consommé 3,3 nymphes de thrips par jour (valeur moyenne des stades de nourritures). Les larves ne mangent pas. Faute de thrips,A. barkeri peut consommer des tétranyches tisserands,Tetranychus urticae (Koch), et leurs œufs, des acariens jaunes adultes,Polyphagotarsonemus latus (Banks), et du pollen de plusieurs plantes. Dans le cas de nourriture insuffisante, du cannibalisme a été observé. Les caractéristiques morphologiques, l'oviposition, l'accouplement et le comportement prédateur sont décrits.
    Notes: Abstract Amblyseius barkeri (Hughes) fed onThrips tabaci (Lind.) at 25°C showed an average duration of 2.2, 0.8 and 3.2 days for the egg, larval and nymphal stages, with mortalities at 1.0, 1.0 and 3.1%, respectively. Females represented 63% of the population and required multiple matings for optimal fertility. The oviposition period was 20.3 days and the average oviposition rate 2.3 eggs per day. The intrinsic rate of increase was 0.22 per day. The expected life span was 29.6 days for ♀♀ and 27.4 days for ♂♂.A. barkeri ♂♂ and ♀♀ both consumed 3.3 nymphs of thrips per day (mean value for the feeding stages). The larva does not take up food. In the absence of thripsA. barkeri was able to consume two-spotted spider mites,Tetranychus urticae (Koch), and their eggs, adult broad mites,Polyphagotarsonemus latus (Banks), and pollen of various plants. Cannibalism was observed when food was lacking. Certain morphological features, egglaying, mating and predatory behaviour are described.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372676
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  • 5
    Electronic Resource
    Electronic Resource
    Host specificity and biology of the weevilNeohydronomus affinis [Coleoptera: Curculionidae] a biological control agent ofPistia stratiotes (1989)
    Springer
    BioControl 34 (1989), S. 299-306 
    Details
    ISSN: 1573-8248
    Keywords: Neohydronomus affinis ; weevil ; biological control ; Pistia stratiotes ; aquatic weed ; host specificity ; Neohydronomus affinis ; charançon ; lutte biologique ; Pistia stratiotes ; mauvaise herbe aquatique ; spécificité
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Un charançon,Neohydronomus pulchellus [Col: Curculionidae], introduit d'Amérique du Sud, contrôle efficacement les populations dePistia stratiotes en Australie. Ce charançon a été importé d'Australie en Floride où en Quarantaine il a été essayé contre 34 espèces de plantes appartenant à 27 familles. Dans les essais d'alimentation sans choix non reproduits, le charançon se nourrit en plus dePistia, des plantes aquatiques:Lemna minor L., Spirodela punctata (Meyer),Orontium aquaticum L.,Limnobium stoloniferum (G. W. Meyer),Azolla caroliniana Willd etSalvinia minima Baker. L'alimentation sur les deux dernières espèces était peu importante. Dans les essais de ponte sans choix, le charançon a pondu seulement sur les plantes aquatiques, à l'exception d'un œuf déposé sur l'espèce terrestre:Kalanchoe tomentosa Baker; les espèces aquatiques étaient:L. stoloniferum, A. caroliniana, S. minima et 2 espèces deLemnaceae. Tous les œufs semblaient le résultat d'une ponte effectuée au hasard ou fortuite; aucun œuf n'a été introduit dans la feuille comme c'est le cas pour la ponte du charançon dans les feuilles dePistia. Les plantes ayant reçu la ponte et permis l'alimentation du charançon ont été testées à nouveau par des essais avec choix,Pistia était la seule espèce attrayante pour la ponte et l'alimentation. Divers aspects de la biologie du charançon, incluant le comportement des larves mineuses, leur alimentation, la réponse des plantes aux attaques du charançon et le comportement de l'adulte ont été discutés.
    Notes: Abstract Waterlettuce,Pistia stratiotes L., has been successfully controlled in Australia with the weevil,Neohydronomus affinis Hustache. In this study, the weevil was tested in quarantine against 34 plant species in 27 families. In non-replicated no-choice tests, it fed and oviposited on 3 species of duckweeds [(Lemna minor L.,Spirodela punctata (Meyer) Thomps.,S. polyrhiza (L.) Schleid.], frogbit [(Limnobium spongia (Bosc.) Steud.], mosquitofern (Azolla caroliniana Willd) and waterfern (Salvinia mimima Baker). Feeding also occurred on golden club (Orontium aquaticum L.) and one egg was laid on the terrestrial panda plant (Kalanchoe tomentosa Baker). Plants oviposited and fed upon were retested in choice tests. The weevils then fed and oviposited exclusively on waterlettuce. Various aspects of weevil biology, including larval feeding and mining, plant response to weevil attack, and adult behavior are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372469
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  • 6
    Electronic Resource
    Electronic Resource
    Uscana caryedoni [Hym.: Trichogrammatidae]: Possibilités d'utilisation en lutte biologique contre la bruche de l'arachide,Caryedon serratus [Col.: Bruchidae] (1989)
    Springer
    BioControl 34 (1989), S. 351-363 
    Details
    ISSN: 1573-8248
    Keywords: hyménoptères parasites ; Uscana caryedoni ; Caryedon serratus ; Piliostigma thonningii ; arachide ; lutte biologique ; Hymenopterous parasites ; Uscana caryedoni ; Caryedon serratus ; Piliostigma thonningii ; groundnuts ; biological control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Summary The trichogrammatidUscana caryedoni Viggiani is a parasitoid of the eggs of bothCaryedon congense Decelle andCaryedon serratus (Olivier), the groundnut bruchid. Both of these beetles lay regularly on the pods ofPiliostigma thonningii, a leguminous tree common in the Congo. In the Bouenza region in the south of the country, the rate of parasitism increased as the pods ripened and affected a maximum of about 40% of the population by November. The bionomics of the parasitoid were studied by rearing it on eggs ofC. serratus in the laboratory. At 30°C, the female parasitoids lived about 5 days and laid on average 66 eggs. Pre-imaginal development took 16 days at 26°2C and 12 days at 30°C. The effect of the density of host eggs on various biological parameters was also studied. A laboratory evaluation indicated that the potential for using the parasitoidU. caryedoni for controlling infestations ofC. serratus on groundnuts was low.
    Notes: Résumé Le trichogrammeUscana caryedoni Viggiani se développe aux dépens des œufs deCaryedon congense Decelle et de ceux de la bruche de l'arachide,Caryedon serratus (Olivier), sur les fruits d'une légumineuse arbustive commune au Congo,Poliostigma thonningii (Schum.). Dans la région de la Bouenza, dans le sud du pays, les taux de parasitisme dus àU. caryedoni s'accroissent au cours de l'année, à mesure que mûrissent les gousses, pour atteindre en novembre près de 40% (taux cumulé). La biologie du parasitoïde a été étudiée au laboratoire sur œufs deC. serratus. A 30°C, la femelle pond en moyenne 66 œufs et vit un peu plus de 5 jours. Le développement préimaginal s'effectue en 16 jours à 26° et 12 jours à 30°. L'effet de la densité de l'hôte sur divers paramètres biologiques du parasite a été étudié. Un essai réalisé dans les conditions du laboratoire a révélé chezU. caryedoni de très faibles potentialités comme agent de limitation des populations deC. serratus dans les stocks d'arachide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372474
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  • 7
    Electronic Resource
    Electronic Resource
    Installation deRhyzobius forestieri [Col., Coccinellidae] sur l'ile de porquerolles (1989)
    Springer
    BioControl 34 (1989), S. 365-372 
    Details
    ISSN: 1573-8248
    Keywords: Rhyzobius forestieri Muls. ; lutte biologique ; acclimatation ; Ile de Porquerolles ; Saissetia oleae Oliv. ; efficacité prédatrice ; Rhyzobius forestieri Muls. ; biological control ; acclimatization ; Island of Porquerolles ; Saissetia oleae Oliv. ; predator effectiveness
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Summary In September 1986Rhyzobius forestieri Muls. was released on clementine trees heavily infested withSaissetia oleae Oliv. Orchard is located in “Conservatoire botanique de l'île de Porquerolles” (South-east of France). Imported from California (USA) byP. Katsoyannos in 1981,R. forestieri has been reared permanently since 1983 in “Station de Zoologie et de Lutte biologique I.N.R.A., Antibes” with a substitution prey,Coccus hesperidum L. multiplied on cucurbitaceous fruits. Twice releases were done at the rate of 50 adults a tree: - first time on 12 clementine trees on September 11th 1986; - second time on 12 other clementine trees on November 11th 1986; Nearly one year later, on 11th September 1987S. oleae andCoccinellidae were sampled for the double purpose to find againR. forestieri and to assess its effectiveness. In conclusion, in spite of the fact that winter, between 1986 and 1987, was a very cold weather, it is possible to consider thatR. forestieri is successfully established in Porquerolles and even then, to be interested with its impact onS. oleae, because an effective reduction in scale numbers, on twigs and on leaves is occurred (proportionately, at least from 4 to 1 and greatest from 10 to 1).
    Notes: Résumé En septembre 1986, un lâcher inoculatif deRhyzobius forestieri Muls. fut effectué dans un verger de clémentiniers lourdement infesté parSaissetia oleae Oliv. et situé au Conservatoire botanique de l'île de Porquerolles. Ramenée de Californie (u.S.A.) parP. Katsoyannos en 1981, une souche deR. forestieri est multipliée de façon permanente, depuis 1983, à la Station de Zoologie et de Lutte biologique I.N.R.A. d'Antibes, à partir d'une proie de substitutionCoccus hesperidum L. élevée sur courges. Les introductions furent effectuées en 2 fois à raison de 50 adultes par arbre: - la première fois le 4.09.1986 sur 12 clémentiniers, - et la deuxième fois, deux mois après, le 11.11.1986 sur 12 autres clémentiniers. Un an après, le 11.09.1987, un échantillonnage des populations de la cochenille et des prédateurs fut réalisé dans le double but de retrouver le prédateur introduit et d'éprouver son efficacité. En conclusion, et malgré un hiver 1986–1987 relativement rigoureux, on peut considérer l'acclimatation deR. forestieri à l'île de Porquerolles comme réussie et déjà s'intéresser à son possible impact sur les populations deS. oleae, dont le degré d'infestation a diminué sensiblement sur les rameaux et significativement sur les feuilles (dans des proportions minimum de 1 à 4 et maximum de 1 à 10).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372475
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  • 8
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    Electronic Resource
    Biological control of the weed,Chromolaena odorata [Asteraceae], byPareuchaetes pseudoinsulata [Lep.: Arctiidae] on Guam and the northern Mariana Islands (1989)
    Springer
    BioControl 34 (1989), S. 531-539 
    Details
    ISSN: 1573-8248
    Keywords: Chromolaena odorata ; Pareuchaetes pseudoinsulata ; biological control ; Guam ; Mariana Islands ; Chromolaena odorata ; Pareuchaetes pseudoinsulata ; lutte biologique ; Ile de Guam
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Chromolaena odorata L. est une mauvaise herbe qui prédomine dans les cultures et les pâturages tropicaux.Pareuchaetes pseudoinsulata Rego Barros [Lepidoptera: Arctiidae] fut élevé en masse et introduit dans les Iles Mariannes du Pacifique Occidental, en l'occurrence Guam, Rota, Tinian, et Saipan, dans le but de lutter contre cette mauvaise herbe. Dans l'année qui suivit l'introduction deP. pseudoinsulata dans l'Ile de Guam, cette mauvaise herbe fut réduite de 100% dans 3 sites sur quatre, contrôlés au moyen de quadrats fixés. La défoliation de cette herbe antérieure à sa floraison, empêche la montée en graine. Dans le cas d'une défoliation amorcée immédiatement après le début de la floraison, on constatait que les graines en développement furent consommées parP. pseudoinsulata ou, le cas échéant, que le poids ainsi que le taux de germination des graines mûres furent sérieusement réduits. Dix-huit mois après son introduction dans l'Ile de Guam, le lépidoptère avait réussi à défeuiller près de 25000 hectares. Ceci constitue le premier rapport sur l'effet quantitatif d'un agent régulateur quelconque surC. adorata et, bien que nous ignorions encore les effets à long terme de cet insecte, ces premiers résultats sont encourageants.
    Notes: Abstract Chromolaena odorata L. is a major weed of tropical plantations and pasture lands.Pareuchaetes pseudoinsulata Rego Barros [Lep.: Arctiidae] was mass-reared and released to control the weed on the Mariana Islands of Guam, Rota, Tinian and Saipan in the western Pacific. One year following establishment ofP. pseudoinsulata on Guam, the weed was reduced 100% at 3 of 4 sites monitored with fixed quadrats. Seed production was prevented if defoliation occurred prior to the beginning of the flowering season. If defoliation occurred shortly after flowering began, the developing seeds were eaten byP. pseudoinsulata or there was a significant reduction in weight and germination of seeds that matured. Eighteen months after establishing on Guam,P. pseudoinsulata had defoliated approximately 25,000 hectares of the weed. This is the 1st report on the quantitative impact of any control agent forC. odorata, and though the long term effect of the insect is still unknown, these results are encouraging.
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    URL: http://dx.doi.org/10.1007/BF02374391
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  • 9
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    Electronic Resource
    Measuring the host preference of parasites: An aid in evaluating biotypes ofAnagrus epos [Hym.: Mymaridae] (1989)
    Springer
    BioControl 34 (1989), S. 551-558 
    Details
    ISSN: 1573-8248
    Keywords: Anagrus epos ; grapes ; Erythroneura ; biological control ; evaluation ; identification ; Anagrus epos ; vigne ; Erythroneura ; lutte biologique ; identification ; préférence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Plusieurs biotypes d'Anagrus epos Girault [Hym.: Mymairdae] ont été importés et évalués pour la lutte biologique contre la cicadelleErythroneura variabilis Beamer, espèce nuisible à la vigne en Californie centrale. Nous avons développé une méthode pratique qui quantifie par un coefficient la préférence. Les biotypes d'Anagrus epos venant de zones géographiques isolées différentes de l'ouest américain et du nord du Mexique ont montré divers degrés de préférence pour les 2 espèces principales de cicadelles. Les mesures de la préférence des biotypes, élevés en laboratoire peuvent fournir des caractères propres à identifier les individus libérés sur le terrain.
    Notes: Abstract Populations ofAnagrus epos Girault are being imported and evaluated for the biological control of variegated grape leafhopper,Erythroneura variabilis Beamer, a newly introduced pest of grapes in central California. To distinguish different biotypes, a field test was developed that quantifies host preference.E. epos collected from geographically isolated regions of western United States and northern Mexico showed different levels of preference towards the variegated leafhopper and its close relative the grape leafhopper,Erythroneura elegantula Osborn, a native to central California. Host preference values may aid in the identification of relased biotypes using leafhopper eggs on leaves sampled from release sites.
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    URL: http://dx.doi.org/10.1007/BF02374393
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  • 10
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    Electronic Resource
    Nutritional requirements of the mycoparasitic fungus Verticillium biguttatum (1989)
    Springer
    European journal of plant pathology 95 (1989), S. 149-156 
    Details
    ISSN: 1573-8469
    Keywords: biological control ; Rhizoctonia solani ; sclerotia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Samenvatting Een synthetisch vloeibaar medium met glucose als koolstofbron, een ammonium- of aminogroep bevattende verbinding als stikstofbron en biotine als groeifactor voldeed aan de voedingseisen vanVerticillium biguttatum. Van de verschillende koolstof- en stikstofbronnen leverden mannitol en twee ammoniumzouten en glutamine de hoogste opbrengsten aan mycelium; de opbrengst aan conidiën was het hoogst met galactose en glutamine. De hoogste opbrengsten aan mycelium en conidiën werden bereikt bij respectievelijk pH 4,3 en 5.1. Ofschoon neutrale en alkalische omstandigheden de groei vanV. biguttatum in het synthetische medium beperkten, werd enige groei vanV. biguttatum waargenomen op vaste voedingsbodems bij pH 7,0 en op sclerotia vanR. solani in natuurlijke grond bij pH 7,2–7,3.
    Notes: Abstract Verticillium biguttatum was able to grow axenically in a synthetic liquid medium with a compound containing ammonium or amino group as nitrogen source, glucose as carbon source and biotin as growth factor. Among various carbon and nitrogen compounds tested, highest mycelial production was achieved with mannitol and with two ammonium salts and glutamine; sporulation reached highest values with galactose and glutamine. Highest yields of mycelium and conidia were obtained at pH 4.3 and 5.1, respectively. Although neutral and alkaline conditions were growth-limiting in the synthetic medium some growth ofV.biguttatum occurred on solid media at pH 7.0 and on sclerotia ofRhizoctonia solani in natural soil at pH 7.2–7.3.
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  • 11
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    Selection of suitable trichogramma strains to control the codling mothCydia pomonella and the two summer fruit tortrix mothsAdoxophyes orana, Pandemis heparana [Lep.: Tortricidae] (1989)
    Springer
    BioControl 34 (1989), S. 19-27 
    Details
    ISSN: 1573-8248
    Keywords: Trichogramma ; Cydia pomonella ; Adoxophyes orana ; selection of species ; biological control ; Trichogramma ; Cydia pomonella ; Adoxophyes orana ; Auswahl von Nützlingsarten ; biologische Schädlingsbekämfung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Es wurden leicht durchführbare Laborverfahren zur Auswahl von geeignetenTrichogramma-Stämmen für den Einsatz in der biologischen Schädlingsbekämpfung erprobt. Zur Feststellung der Eignung gegen den ApfelwicklerCydia pomonella L. sowie gegen die ApfelschalenwicklerartenAdoxophyes orana F.R. undPandemis heparana Schiff. erfolgten Prüfungen an 17 verschiedenenTrichogramma-Stämmen. In einer Versuchsreihe wurde die Leistung der Trichogrammen bei der Parasitierung von Eiern der verschiedenen Zielwirte erfaßt. Eine weitere Serie von Wahlversuchen diente zur Feststellung der Präferenz derTrichogramma-Weibchen sowohl bei der Suche von Schädlingseiern als auch bei der Parasitierungsleistung bei gleichzeitigem Angebot des StandardwirtesSitotroga cerealella Oliv. Ein Stamm vonT. dendrolimi aus der Volksrepublik China ließ gegenüber allen anderen geprüften Stämmen eine wesentlich höhere Parasitierungsleistung bei allen der vier genannten Wirte erkennen. In Wahlversuchen zeigte dieser Stamm eine nahezu ausgewogene Präferenz zwischen den ZielwirtenC. pomonella undA. orana sowie dem Ersatzwirt in der MassenzuchtS. cerealella. 11 lokale Stämme, die in Obst- und Rebenanlagen verschiedener Gebiete der Bundesrepublik Deutschland gesammelt wurden, wurden getrennt gezüchtet. Vier dieser lokalen Stämme, darunterT. embryophagum, ließen deutlich die Bevorzugung von Eiern der SchädlingeC. pomonella undA. orana gegenüber Eiern vonS. cerealella erkennen. Bei einem dieser Stämme war die Bevorzugung so deutlich, daß die Eier vonS. cerealella bei einem gleichzeitigen Angebot von Eiern der genannten Schädlinge fast total abgelehnt wurden. Wegen dieser Eigenschaft nimmt dieser Stamm nach der Durchführung einer Passage in Wicklereiern nur zögernd die Eier vonS. cerealella in der Massenzucht an. Die übrigen 12 Stämme wiesen geringere Parasitierungsleistung und/oder schwächere Präferenz gegenüber den Zielwirten auf. Auf der Grundlage dieser Untersuchungen erfolgte 1984 bis 1986 die Massenvermehrung und Freilassung von vier dieserTrichogramma-Stämme, darunterT. dendrolimi undT. embryophagum, zur Bekämpfung von Apfelschädlingen. Die Publikation der Ergebnisse dieser Felduntersuchungen ist in der hiesigen Zeitschrift vorgesehen.
    Notes: Abstract Simple laboratory methods to select candidateTrichogramma strains for use in biological control were tried. 17 strains were screened for their suitability against the codling mothCydia pomonella L. as well as the 2 summer fruit tortrix mothsAdoxophyes orana F.R. andPandemis heparana Schiff. In one set of experiments, the capacity ofTrichogramma to parasitize each of these target pests was examined, in another set, the preference ofTrichogramma to contact and parasitize the target pests compared to the standard mass rearing hostSitotroga cerealella was assessed in choice experiments. A strain ofTrichogramma dendrolimi from the People's Republic of China was found to have the highest fecundity with all the 4 hosts tested. In choice experiments, however, this strain was shown to have a near equal preference between the target tortrix pestsC. pomonella, A. orana and the replacement hostS. cerealella. 11 localTrichogramma strains collected from fruit orchards and vineyards in different locations in the Federal Republic of Germany were reared separately. Four of these local strains, one identified asT. embryophagum, showed clear preference to the tortrix pestsC. pomonella andA. orana compared toS. cerealella. The preference of one of these strains was particularly strong and amounted to a near total rejection ofS. cerealella eggs in the presence of any of the 2 tortrix pests. The remaining 12 strains had weaker parasitization capacity and/or less preference to the target pests. Four of the strains tested in these experiments, includingT. dendrolimi andT. embryophagum, were mass reared and released in apple orchards between 1984 and 1986. The results of these field experiments are planned to be published in this journal.
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  • 12
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    Studies ontrichogramma buesi as a biocontrol agent againstPieris rapae in Egypt (1989)
    Springer
    BioControl 34 (1989), S. 447-451 
    Details
    ISSN: 1573-8248
    Keywords: Trichogramma buesi ; egg-parasites ; Pieris rapae ; biological control ; the cabbage worm ; Trichogramma buesi ; parasites oophages ; Pieris rapae ; lutte biologique ; Noctuelle du chou
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Trichogramma buesi a été élevé au laboratoire sur les œufs de la teigne méditerranéenne de la farineAnagasta Kuehniella. La période d'incubation des œufs du parasite était de 27 h à 23 °C et 22 h à 27 °C. Le stade larvaire durait 3,6 et 3,2 jours, le stade prépupe durait 16 et 23h et la pupe durait 5,4 et 4,6 jours à 23 °C et 27 °C respectivement. La durée totale du développement (de l'œuf à l'adulte) était en moyenne 9,2; 9,4 et 9,1 jours quand le parasite s'élevait à 27 °C sur les œufs dePieris rapae, deSpodoptera littoralis et d'A. Kuehniella respectivement. Le sex-ratio chezT. buesi était 1 ♂: 1,3 ♀ au laboratoire. La descendance quotidienne et le nombre total d'individus produits/♀ furent respectivement de 5,1 et de 98,2 adultes. La ♀ parasite nourrie de miel, vivait 10,7 jours à 27°C et 12,1 jours à 23 °C.
    Notes: Abstract Trichogramma buesi was reared in the laboratory on eggs of the Mediterranean flour moth,Anagasta kuehniella. The incubation period of the parasite's egg was 27 h at 23 °C and 22 h at 27 °C. The larval stage lasted 3.6 and 3.2 days, the pre-pupa lasted 16 and 23 h, and the pupa lasted 5.4 and 4.6 days at 23° and 27°C, respectively. The total developmental time (from egg to adult) averaged 9.2, 9.4, and 9.1 days when the parasite was reared on eggs ofPieris rapae, Spodoptera littoralis, andA. kuehniella, respectively, at 27 °C. Sex ratio inT. buesi was 1 ♂: 1 ♀ in nature and 1 ♂: 1.3 ♀ in the laboratory. The daily and total numbers or progeny produced/female were 5.1 and 98.2 adults, respectively. The parasite female, fed on honey, lived 10.7 days at 27 °C and 12.1 days at 23 °C. Percentages of parasitism byT. buesi on eggs ofP. rapae collected from cabbage fields ranged between 0 and 31.5 % in 1985 and betwcen 0 and 36.4% in 1986 during July through December. The respective figures on eggs collected from turnip fields were 16–42.2% and 12.5–32.1% during November and December.
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    URL: http://dx.doi.org/10.1007/BF02374381
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  • 13
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    Bionomics ofTrioxys indicus [Hym.: Aphidiidae], a parasitoid ofAphis craccivora [Hem.: Aphididae]: 31. Effect of host haemolymph on the numerical response of the parasitoid (1989)
    Springer
    BioControl 34 (1989), S. 581-586 
    Details
    ISSN: 1573-8248
    Keywords: Trioxys indicus ; Aphidiidae ; Aphis craccivora ; Aphididae ; numerical response ; host-haemolymph ; kairomones ; biological control ; mortality factor ; Trioxys indicus ; Aphidiidae ; Aphis craccivora ; Aphididae ; réponse numérique ; haemolymphe de l'hôte ; kairomones ; lutte biologique ; facteur de mortalité
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé L'influence des kairomones sur la réponse numérique du parasitoïdeTrioxys indicus vis-à-vis de son hôteAphis craccivora à densité variable a été étudiée. Les kairomones (appliquées comme extrait aqueux de l'hôte) accroissent d'une manière significative le taux de parasitisme et de multiplication et l'aire de découverte des parasitoïdes et aussi les valeurs K de la mortalité de l'hôte à toutes les densités de parasitoïde introduites (1, 2, 4, 8, 12 et 16 individus) à l'intérieur de récipients ayant environ 200 hôtes. Le sex-ratio de la descendance F1 décroît à des densités de parasitoïdes plus faibles et reste plus ou moins inchangé à des densités de parasitoïdes plus fortes après l'application de kairomones. Les présentes recherches indiquent que si les kairomones sont appliquées correctement, le nombre d'hôtes détruits par un parasitoïde stimulé sera d'environ 200, deux fois le nombre rapporté antérieurement, ainsi quelques parasitoïdes seront nécessaires pour limiter une population estiméc des hôtes.
    Notes: Abstract The influence of kairomones on the numerical response of the parasitoidTrioxys indicus against its hostAphis craccivora at its varying density was studied. The kairomones (applied as aqueous extract of the host) significantly enhanced the rate of parasitisation and multiplication and the area of discovery of the parasitoid and also the K-values of mortality of the host at all parasitoid densities introduced (1, 2, 4, 8, 12 and 16 parasitoids) into troughs having about 200 hosts. The sex-ratio of F1 offspring decreased at lower parasitoid densities and remained more or less unchanged at higher parasitoid densities after the application of kairomones. The present findings indicate that if kairomones are applied properly, the number of hosts destroyed by a stimulated parasitoid will be about 200, twice the number reported earlier, thus fewer parasitoids will be needed to regulate an estimated population of the hosts.
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    URL: http://dx.doi.org/10.1007/BF02374396
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  • 14
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    Nutritional disturbances of young pines in a dry heath forest (1989)
    Springer
    Plant and soil 113 (1989), S. 229-235 
    Details
    ISSN: 1573-5036
    Keywords: aluminium ; calcium ; foliar analysis ; magnesium ; nitrogen ; nutritional disturbance ; Pinus sylvestris L. ; potassium ; soil analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Tree decline has been observed recently in 25–30 year old pine stands inCladina andCalluna-type heath forests in the Hämeenkangas and Pohjankangas areas of southwestern Finland. The trees had grown more or less normally for 15 years. During the following 7 to 8 years increased growth occurred. From 1982 to 1984, however, the trees revealed a sudden reduction in height increment. Additionally, some trees were marked by poor apical shoot dominance. Occasionally complete crown dieback was observed. The trees retained only one to three years' needles. These needles often were characterized by a brownish yellow discoloration. Chemical foliar and soil analysis indicate both a nitrogen deficiency and a deficiency in calcium and magnesium related to the relatively high aluminium levels in the soil. In the needles of affected trees phosphorus and especially potassium concentrations were higher than normally. The low content of nitrogen, calcium and magnesium in the soil is related to the acidic, nutrient-poor bedrock, and the low cation exchange capacity. Also the leaching of nutrients, the shallow and poor quality of the humus layer, and the removal of nutrients by tree harvesting may have effected on the nutritional disturbances.
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    URL: http://dx.doi.org/10.1007/BF02280185
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  • 15
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    Mineralization of carbon and nitrogen in soil samples taken from three fertilized pine stands: Long-term effects (1989)
    Springer
    Plant and soil 114 (1989), S. 99-106 
    Details
    ISSN: 1573-5036
    Keywords: ammonium nitrate ; apatite ; biotite ; carbon ; fertilization ; forest soil ; mineralization ; nitroform ; nitrogen ; nutrients ; pH ; urea ; ureaformaldehyde
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seven years after fertilization the rate of CO2 production in the soil samples taken from the organic horizons of a poor pine forest site (Calluna vulgaris site type), treated with urea or ammonium nitrate with lime, was lower than that in the unfertilized soil. The same trend was also observed in samples of theEmpetrum-Calluna site type 14 years after fertilization. In the more fertileVaccinium myrtillus site type these rapidly-soluble N fertilizers had a long-term enhancing effect on the production of CO2. Apatite and biotite eliminated the decreasing effect of urea on the production of CO2. One reason for this might be the long-term increase in soil pH caused by apatite and biotite, or their constituents (Ca, Mg, K, P). Nitroform (a slow-releasing N fertilizer) had no statistically significant effect on the production of CO2 in soil samples from any of the forest types. Despite the high N mineralization in the samples from nitroform fertilized soils there was no nitrification, and the high content of total N indicated that after nitroform fertilization the losses of N were low. The correlation between the net mineralization values for C (CO2 production) and N was poor. However, multiple linear regression analysis, which also took into account the effect of nutrients and pH, indicated that there was a link between the mineralization of C and N.
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    URL: http://dx.doi.org/10.1007/BF02203087
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  • 16
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    Ammonia volatilization during aerobic and anaerobic manure decomposition (1989)
    Springer
    Plant and soil 115 (1989), S. 35-41 
    Details
    ISSN: 1573-5036
    Keywords: C/N ratio ; fatty acids ; immobilization ; nitrogen ; straw
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ammonia volatilization, nitrogen immobilization, carbon decomposition and formation of volatile fatty acids was investigated in a laboratory incubation experiment with fresh poultry manure, to which increasing amounts of straw were added. Less than 1% of the manure nitrogen was volatilized as ammonia during anaerobic decomposition due to low pH values. In aerobic manure alkaline conditions prevailed and between 9 to 44% of the nitrogen was volatilized as ammonia. The volatilization courses could be described by a parallel first-order model. Increasing straw additions reduced ammonia volatilization during aerobic decomposition. Straw caused no immobilization of nitrogen under anaerobic conditions. In aerobic manure, nitrogen was mainly bound in organic forms whereas in anaerobic manure about two-thirds of the nitrogen was in ammonium form. C/N ratios in the organic matter of anaerobic manure were higher (33.1–87.5) than in the aerobic manure (9.5–18.0).
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    URL: http://dx.doi.org/10.1007/BF02220692
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  • 17
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    Effect of culture filtrates of seventeen fungicolous fungi on sporulation of cucumber powdery mildew (1989)
    Springer
    European journal of plant pathology 95 (1989), S. 95-98 
    Details
    ISSN: 1573-8469
    Keywords: biological control ; hyperparasites ; Sphaerotheca fuliginea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Samenvatting Cultuurfiltraten van 17 verschillende mycoparasitaire schimmelsoorten, die waren geïsoleerd van andere schimmels, werden getoetst op hun werkzaamheid tegen komkommermeeldauw. Alle cultuurfiltraten reduceerden het percentage gezonde conidioforen. De verschillen in activiteit tussen de diverse behandelingen waren echter niet zo opvallend als bij gebruik van sporensuspensies. De beste resultaten werden verkregen met een cultuurfiltraat vanCalcarisporium arbuscula.
    Notes: Abstract Culture filtrates of 17 different fungal species thriving upon other fungi were tested for their ability to reduce sporulation of cucumber powdery mildew,Sphaerotheca fuliginea. All culture filtrates reduced the number of healthy conidiophores. However, the differences in activity between the various treatments were not as conspicuous as after application of spore suspensions. The best results were obtained with culture filtrates ofCalcarisporium arbuscula. These reduced the number of healthy conidiophores to ca. 2% of the unsprayed control plants.
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    URL: http://dx.doi.org/10.1007/BF01974288
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  • 18
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    Experimental inundative releases of different strains of the egg parasite Trichogramma in Brussels sprouts (1989)
    Springer
    European journal of plant pathology 95 (1989), S. 129-142 
    Details
    ISSN: 1573-8469
    Keywords: biological control ; egg parasites ; Brussels sprouts ; Mamestra brassicae ; Pieris brassicae ; Pieris rapae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Samenvatting In spruitkool kan schade veroorzaakt worden door rupsen van vijf soorten Lepidoptera. Inundatieve biologische bestrijding met de eiparasietTrichogramma (Hymenoptera, Trichogrammatidae) zou een alternatief kunnen zijn voor intensieve chemische gestrijding. In veldexperimenten (1982–1985) is de effectiviteit van vierTrichogramma spp. stammen vergeleken om de uitkomsten van laboratoriumonderzoek naar criteria voor de selectie van geschikte natuurlijke vijanden te evalueren. Selectiecriteria zijn gebaseerd op eigenschappen van het zoek- en parasiteringsgedrag van de parasieten, o.a. parasiteringsactiviteit bij lage temperatuur en gastheer-preferentie. Mamestra brassicae (Noctuidae) was de talrijkste gastheersooort, met een gemiddelde dichtheid van 0,2–2,0 eieren/plant gedurende een groot deel van het seizoen (juni–september). Een extreem hoge piekdichtheid (12 eieren/plant) deed zich voor in 1982. In andere jaren was de piekdichtheid ongeveer 2,5 eieren/plant. Eieren vanM. brassicae werden het meest geparasiteerd door stam 57 (T. evanescens), maar zelfs het hoogste gemiddelde seizoenspercentage parasitisme (52%) was niet voldoende voor een effectieve bestrijding. EenT. maidis stam (11) gaf de beste resultaten tegenPieris brassicae enP. rapae (Pieridae), maar parasitisme was laag (〈30%) en vrijwel beperkt tot piekdichtheden hoger dan 0,5 eieren/plant, die voorkwamen in 1982 en 1985.Plutella xylostella (Plutellidae) was soms talrijk, maar eiparasitisme leek niet voor te komen. De dichtheid vanEvergestis forficalis (Pyralidae) was gering in alle jaren. Relatief lage gastheerdichtheden kunnen een beperkende factor geweest zijn voor het optreden van een effectieve percentages eiparasitisme. De resultaten tonen aan dat er een overeenstemming is tussen selectiecriteria die in het laboratorium zijn onderzocht en de effectiviteit van geselecteerde stammen in het veld.
    Notes: Abstract The effectiveness of inundative releases of four strains of the egg parasiteTrichogramma (Hymenoptera, Trichogrammatidae) to control five lepidopterous species infesting Brussels sprouts crops in the Netherlands was examined in small-scale field experiments in 1982–1985. Strains were selected on the basis of behavioural characteristics investigated in laboratory experiments, i.e. parasitization activity at low temperature and host-species preference.Mamestra brassicae (Noctuidae) was the most abundant host species. Its density usually averaged between 0.5 and 2.0 eggs/plant throughout most of the season (June–September). A very high peak density of 12 eggs/plant occurred in 1982. In other years the peak was below 2.5 eggs/plant. Correspondence between the observed patterns of parasitism and behavioural characteristics of the strains was in general present. A strain ofT. evanescens (no. 57), with a high activity at 12°C, performed best againstM. brassicae. However, even its highest rate of parasitism (52%) was not sufficiently effective. A strain ofT. maidis (no. 11) performed best againstPieris brassicae andP. rapae (Pieridae), but parasitism remained low (〈30%) and was generally limited to peak densities (〈0.5 eggs plant) occurring in 1982 and 1985.Plutella xylostella (Yponomeutidae) was an abundant species in some years, but parasitism of its eggs was never observed. Egg densities ofEvergestis forficalis (Pyralidae) remained low in all years. The relationship between parasitims and host density and the influence of the parasite-release rate are discussed. Low host densities may have been a limiting factor for effective parasitism.
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  • 19
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    Effect of seventeen fungicolous fungi on sporulation of cucumber powdery mildew (1989)
    Springer
    European journal of plant pathology 94 (1989), S. 185-190 
    Details
    ISSN: 1573-8469
    Keywords: biological control ; hyperparasites ; Sphaerotheca fuliginea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Samenvatting Negentien isolaten behorend tot 17 verschillende schimmelsoorten werden getoetst op hun bruikbaarheid voor de biologische bestrijding van komkommermeeldauw aan de hand van effecten op sporulatie. Meer dan de helft van de getoetete isolaten reduceerde het aantal gezonde conidioforen tot minder dan 10%. De werking vanTilletiopsis albescens was enigszins beter dan die van de meestal gebruikte hyperparasietAmpelomyces quisqualis. Van de getoetste schimmels werden er drie, n.l.A. quisqualis, Aphanocladium album enT. albescens, geselecteerd voor kasproeven.
    Notes: Abstract Nineteen isolates of 17 different fungal species thriving upon other fungi were tested for their ability to control sporulation of cucumber powdery mildew,Sphaerotheca fuliginea. More than half of the fungi reduced the number of healthy conidiophores to less than 10%.Tilletiopsis albescens was superior toAmpelomyces quisqualis. Three species, viz.A. quisqualis, Aphanocladium album andT. albescens, were selected for further greenhouse experiments.
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    URL: http://dx.doi.org/10.1007/BF02006544
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  • 20
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    Factors affecting the colonisation of a root system by fluorescent Pseudomonads: The effects of water, temperature and soil microflora (1989)
    Springer
    Plant and soil 116 (1989), S. 247-256 
    Details
    ISSN: 1573-5036
    Keywords: biological control ; PGPR ; Pseudomonads ; rhizobacteria ; rhizosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The colonisation of a radish root system by strains ofPseudomonas fluorescens, selected for their ability to promote potato and radish growth under different environmental conditions is reported. In pot experiments colonisation of different parts of the root system was measured at different temperatures, in different watering regimes and in sterile and recropped soil. Root colonisation was extensive but populations were highest on the upper root system and their distribution throughout the root system was greatly affected by environmental factors. percolation of water through the soil and partial soil sterilisation enhanced colonisation but the effects of temperature and recropping were complex. Growth promotion was unpredictable and there was no simple relationship between PGPR colonisation and stimulation of plant growth.
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    URL: http://dx.doi.org/10.1007/BF02214554
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  • 21
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    A comparison of methods for measuring the colonisation of a root system by fluorescent Pseudomonads (1989)
    Springer
    Plant and soil 116 (1989), S. 239-246 
    Details
    ISSN: 1573-5036
    Keywords: biological control ; PGPR ; Pseudomonads ; rhizobacteria ; rhizosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Methods are described for measuring the colonisation of a radish (Raphanus sativus) root system by seedlings with rifampicin resistant fluorescent pseudomonads by dilution plating, and which would take account of differences in root morphology. Differences in the levels of pseudomonad colonisation was highly dependent on the units in which surface areas was expressed. Population levels are expressed using estimates of surface area based on root length, tap-root length and root weight. The best estimate of surface area was root length, but the most practical method was surface area calculated as a function of dry weight. This method could differentiate differences in the levels of root colonisation independent of differences in root morphology and was efficient enough to allow the routine processing of a large number of replicate root samples.
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    URL: http://dx.doi.org/10.1007/BF02214553
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  • 22
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    The effectiveness and competitiveness of some Indonesian Rhizobium strains on tropical legumes grown in four soil types of Java (1989)
    Springer
    Plant and soil 117 (1989), S. 146-150 
    Details
    ISSN: 1573-5036
    Keywords: bacteria ; legume growth ; nitrogen ; nodulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Several Indonesian and some imported Rhizobium strains were assessed for their effectiveness in nodulating four legume species in four soil types of Java. Naturally occurring Rhizobia formed effective symbioses onVigna unguiculata, Macroptilium atropurpureum andDesmodium heterocarpon in all four soils and the applied strains, with some exceptions, did not infect a majority of nodules of these legumes.Centrosema pubescens was more specific in its Rhizobia requirements and applied strains formed effective symbioses in two clay soils, but not in two sandy loam soils.
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    URL: http://dx.doi.org/10.1007/BF02206268
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    Phosphorus and nitrogen retention in five Precambrian shield wetlands (1989)
    Springer
    Biogeochemistry 8 (1989), S. 185-204 
    Details
    ISSN: 1573-515X
    Keywords: phosphorus ; nitrogen ; wetlands ; beaver ponds ; conifer swamp ; sedge fen ; Precambrian shield ; nutrient retention ; mass balance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Phosphorus and nitrogen mass balances of five wetlands (two beaver ponds, two conifer-Sphagnum swamps and one sedge fen) situated in three catchments in central Ontario, Canada, were measured. Monthly and annual input-output budgets of total phosphorus (TP), total nitrogen (TN), total organic nitrogen (TON), total inorganic nitrogen (TIN), ammonium ion (NH4 + -N), nitrate (NO 3 − -N) and dissolved organic carbon (DOC) were estimated for the five wetlands during the 1982–83 and 1983–84 water years. Except for the deepest beaver pond (3.2 m) which had annual TP retention of −44% (−0.030 ± 0.015 g m−2 yr−1), the wetlands retained 〈 0.001 to 0.015 g M−2 yr−1 ; however, this wasless than 20% of the inputs and the estimated budget uncertainties were equal to or greater than the retention rates. Annual TN retentions ranged from −0.44 to 0.56 g m−2 yr−1 (−12 to 4%) but were not significantly different from zero. The wetlands transformed nitrogen by retaining TIN (16 to 80% RT) and exporting an equivalent amount as TON (−7 to 102% RT). The beaver ponds, however, retained NO 3 − while NH 4 + was passed through or the outputs exceeded the inputs. In contrast, the conifer swamps retained both NH 4 + and NO 3 − . DOC fluxes into and out of the beaver ponds were equal (−18 and 4% RT) but output from the conifer swamps exceeded input by 〉 90%. Marked seasonal trends in nutrient retention were observed. Nutrient retention coincided with low stream flow, increased evapotranspiration and biotic uptake during the summer. Net nutrient export occurred during the winter and spring when stream flows were highest and biotic uptake was low.
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    URL: http://dx.doi.org/10.1007/BF00002888
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    Indirect measures of N2 fixation in common bean (Phaseolus vulgaris L.) under field conditions: The role of lateral root nodules (1989)
    Springer
    Plant and soil 113 (1989), S. 181-187 
    Details
    ISSN: 1573-5036
    Keywords: acetylene reduction ; breeding ; inbred backcross lines ; leghemoglobin ; nitrogen ; rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The role of lateral root nodules in N2 fixation and the relationships between total shoot N and several traits which influence or control N2 fixation in common bean (Phaseolus vulgaris L.)i.e., acetylene reduction value, specific nodule activity, leghemoglobin concentration, total leghemoglobin and nodule mass, were investigated in field studies. Significant variation among bean lines was observed for all the traits measured. Lines varied for the proportion of total N accumulated up to the R3 growth state, thus measurements of total shoot N near maturity (e.g., R7) provided a better estimate of total N2 fixation than measurements taken at an early growth stage. Nodule mass was correlated with acetylene reduction and total leghemoglobin, and total leghemoglobin was correlated with acetylene reduction value. Total shoot N at R7 was correlated with seasonal means of nodule mass and number, acetylene reduction value and total leghemoglobin. For all traits except total leghemoglobin, values for lateral roots were more highly correlated with total shoot N than were values for either crown roots or the whole root system. Seed yield was most highly correlated with nodule mass of the lateral roots. These results will be useful in devising breeding strategies for improved N2 fixation of the host plant.
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    URL: http://dx.doi.org/10.1007/BF02280179
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    Alfalfa N2-fixation enhances the phosphorus uptake of walnut in interplantings (1989)
    Springer
    Plant and soil 113 (1989), S. 291-293 
    Details
    ISSN: 1573-5036
    Keywords: agroforestry ; interspecies transfer ; nitrogen ; nitrogen fixation ; nutrient cycling ; pH ; phosphorus ; rhizosphere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Walnut tree seedlings exhibited greater phosphorus (P) uptake from32P-labelled hydroxyapatite when interplanted with alfalfa than with other walnuts, black locust, or orchard grass. Three mechanisms are proposed as possible explanations of this enhnaced P uptake by walnut. In this study, diffusion of solubilized apatite-P to the roots of walnut at points of walnut-alfalfa root intersection is believed to be the operative mechanism. Phosphorus is solubilized due to rhizosphere acidification of alfalfa during nitrogen fixation. These results underscore the interdependence of nutrient cycles. Enhancement of the phosphorus cycle through manipulation of the nitrogen cycle has important implications for world food and fiber production.
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    URL: http://dx.doi.org/10.1007/BF02280196
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    Nitrogen release from roots of alfalfa and soybean grown in sand culture (1989)
    Springer
    Plant and soil 116 (1989), S. 77-84 
    Details
    ISSN: 1573-5036
    Keywords: alfalfa ; amino acids ; ammonium ; Glycine max (L.) Merr. ; leachates ; lucerne ; Medicago sativa L. ; nitrogen ; rhizosphere ; root exudates ; soyabean
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract An enclosed root chamber containing sterile sand medium was used to study net nitrogen (N) release from actively growing root systems of ‘Saranac’ alfalfa (Medicago sativa L.) and ‘Fiskeby V’ soybean (Glycine max L. Merr.). Plants were inoculated with a rhizobial strain appropriate to each host, irrigated with N-free nutrient solution, and grown either to 85 or to 173 d after germination (alfalfa) or to physiological maturity (soybean). Alfalfa released 4.5% of symbiotically-fixed plant N into the root zone over its growth period; soybean released 10.4% of plant N. Root zone leachates were analyzed for total N and for amino acid and ammonium content. Significant ammonium-N release occurred from the alfalfa but not the soybean root system; little amino-N was released by root systems of either species. Shoot harvest and water deficit caused increased release of N from alfalfa roots. The results provide evidence that alfalfa and soybean released significant proportions of their N into the root zone, and indicate that while substantial ammonium-N was released from alfalfa roots, passive leakage of amino-N was not a primary mechanism for N release from root systems of either species.
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    URL: http://dx.doi.org/10.1007/BF02327259
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    Effects of continuous nitrogen application and nitrogen preconditioning on nodulation and growth ofCeanothus griseus varhorizontalis (1989)
    Springer
    Plant and soil 118 (1989), S. 181-187 
    Details
    ISSN: 1573-5036
    Keywords: actinorhizal ; Ceanothus ; Frankia ; nitrogen ; propagation ; inoculation ; nodulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Rooted cuttings ofCeanothus griseus varhorizontalis were irrigated with 0, 10, 20, 50, 75 or 100ppm nitrogen as NH4NO3 for eight weeks prior to inoculation with infectiveFrankia. After inoculation, half of the plants for each treatment nitrogen level continued to be irrigated with the preconditioning nitrogen level and half were given no more supplemental nitrogen. For plants continuously receiving nitrogen, nodule initiation (nodule number) was inversely correlated with increasing supplemental nitrogen levels, and suppressed above 50 ppm N. Leaf nitrogen above 2% in continuous-N plants correlated with greatly reduced or suppressed nodulation. Plants maintained after inoculation without supplemental nitrogen showed influence of the prior nitrogen treatment on nodulation. Preconditioning at 50 ppm and above greatly reduced the number of nodules formed. The evidence suggests that stored internal nitrogen can regulate nodulation. Plant biomass accumulated maximally when nodulation was suppressed, at 75 and 100 ppm supplemental N applied continuously. Internode elongation during the nodulation period occurred only on nodulated plants, or in the presence of supplemental N (10 ppm and above).
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    URL: http://dx.doi.org/10.1007/BF02232805
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    Nutrient losses during a winter low-intensity prescribed fire in a Mediterranean forest (1989)
    Springer
    Plant and soil 120 (1989), S. 69-77 
    Details
    ISSN: 1573-5036
    Keywords: cations ; nitrogen ; nutrient losses ; prescribed fire
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Losses of N, P, K and Ca were measured during a prescribed burning in a French MediterraneanPinus halepensis forest, with understorey ofQuercus coccifera. Nutrient loss was measured by difference between the quantity of a nutrient in the fuel before burning and that found in the postfire remains which were harvested or recovered in small trays. Reduction in fuel weight amounted to 77%, losses from initial fuel elements amounted to 77% for N, 54% for K and 35% for P. No significative loss of Ca was measured. Burning resulted in 7 t ha−1 fuel reduction and in loss of 55 kg ha−1N, 8.5 kg ha−1K and 1.0 kg ha−1P.
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    URL: http://dx.doi.org/10.1007/BF02370292
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    Nitrogen-15 balances for urea and neem coated urea applied to lowland rice following two cowpea cropping systems (1989)
    Springer
    Plant and soil 120 (1989), S. 233-241 
    Details
    ISSN: 1573-5036
    Keywords: added nitrogen interaction ; green manure ; 15N ; N loss ; neem ; nitrate ; nitrogen ; Oryza sativa L. ; Vigna unguiculata (L.) Walp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Little is known about whether the high N losses from inorganic N fertilizers applied to lowland rice (Oryza sativa L.) are affected by the combined use of either legume green manure or residue with N fertilizers. Field experiments were conducted in 1986 and 1987 on an Andaqueptic Haplaquoll in the Philippines to determine the effect of cowpea [Vigna unguiculata (L.) Walp.] cropping systems before rice on the fate and use efficiency of15N-labeled, urea and neem cake (Azadirachta indica Juss.) coated urea (NCU) applied to the subsequent transplanted lowland rice crop. The pre-rice cropping systems were fallow, cowpea incorporated at the flowering stage as a green manure, and cowpea grown to maturity with subsequent incorporation of residue remaining after grain and pod removal. The incorporated green manure contained 70 and 67 kg N ha−1 in 1986 and 1987, respectively. The incorporated residue contained 54 and 49 kg N ha−1 in 1986 and 1987, respectively. The unrecovered15N in the15N balances for 58 kg N ha−1 applied as urea or NCU ranged from 23 to 34% but was not affected by pre-rice cropping system. The partial pressure of ammoniapNH3, and floodwater (nitrate + nitrite)-N following application of 29 kg N ha−1 as urea or NCU to 0.05-m-deep floodwater at 14 days after transplanting was not affected by pre-rice cropping system. In plots not fertilized with urea or NCU, green manure contributed an extra 12 and 26 kg N ha−1, to mature rice plants in 1986 and 1987, respectively. The corresponding contributions from residue were 19 and 23 kg N ha−1, respectively. Coating urea with 0.2g neem cake per g urea had no effect on loss of urea-N in either year; however, it significantly increased grain yield (0.4 Mg ha−1) and total plant N (11 kg ha−1) in 1987 but not in 1986.
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    Root-induced nitrogen mineralisation: A theoretical analysis (1989)
    Springer
    Plant and soil 117 (1989), S. 185-193 
    Details
    ISSN: 1573-5036
    Keywords: carbon ; exudation ; mineralisation ; nitrogen ; rhizosphere ; root ; uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The possibility is examined that carbon (C) released into the soil from a root could enhance the availability of inorganic nitrogen (N) to plants by stimulating microbial activity. The release of soluble C compounds from roots is assumed to occur by one of two general processes: cortical cell death or exudation from intact cells. On the basis of several assumptions chosen to allow maximal amounts of N mineralisation to be calculated, greater amounts of net N mineralisation are theoretically possible at realistic soil C:N ratios of bacteria are grazed by predators such as protozoa, than if bacteria alone are active. More N is mineralised when the substrate released from the root has a high C:N ratio (as in cell death) than when it is relatively N-rich. The amounts of N that a root might realistically cause to be mineralised are unlikely to account entirely for high nitrate inflow rates that have been measured experimentally. However there are circumstances in which the loss of C from roots is essential if any N is to be mineralised and obtained by plants.
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    URL: http://dx.doi.org/10.1007/BF02220711
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    Effects of nutrient additions on litter production and nutrient return in a nutrient-poor Cape fynbos ecosystem (1989)
    Springer
    Plant and soil 117 (1989), S. 227-235 
    Details
    ISSN: 1573-5036
    Keywords: fynbos ; litter production ; nitrogen ; nutrient additions ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Litter production and N and P return were determined at bimonthly intervals for two years in 10×5 m plots, amended with a complete factorial fertilizer addition of N as NH4NO3(Na), P as Ca3(PO4)2(Pa) and a mixture of all essential nutrients excluding N and P (Ma) in a 4–7-year-old post-fire sand-plain lowland fynbos ecosystem, South Africa. Litter production increased with vegetation age, was highly seasonal and peaked from late spring to mid-summer (November to January). No significant differences in annual litter production and N return were found in response to the nutrient treatments, although both tended to increase during the second year in response to Na and Ma. Phosphorus return increased significantly with Pa, and to a lesser extend, N3, during the first year, whereas it increased in response to Na and Ma and decreased in the Pa amended plots during the second year. The nutrient treatments did not result in a change in the timing of the annual peak litter production period or in the plant growth form composition of the litter. The litter layer dry mass and N and P contents increased in response to Na and Ma, while Pa resulted in an increased P content. The evidence from this study indicates that the vegetative growth of the evergreen sclerophyllous shrubs and hemicryptophytes of sand-plain lowland fynbos is not only limited by N, as shown by other studies on shoot growth and vegetation cover, but also by one or more other nutrients excluding P.
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    A comparison of organic and inorganic nitrogen fertilizers: Their nitrate-N and ammonium-N release characteristics and effects on the growth response of lettuce (Lactuca sativa L. cv. Fortune) (1989)
    Springer
    Plant and soil 115 (1989), S. 135-144 
    Details
    ISSN: 1573-5036
    Keywords: growth response ; inorganic fertilizer ; Lactuca sativa L. ; leaching loss ; nitrogen ; organic fertilizer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The response of pot grown lettuce to inorganic (ammonium nitrate) and organic (dried blood and Protox) N fertilizers was determined at two temperature regimes (15°C day/10°C night and 20°C day/15°C night) and related to the NH4−N and NO3−N release characteristics of each material. The N release characteristics of the organic materials matched the N requirements of lettuce more closely than the inorganic fertilizer. However, was rapidly released from the protein based materials such that composts were depleted of available fertilizer N at the same time irrespective of the form supplied. The warmer temperature regimes resulted in a more rapid depletion of the fertilizers due to biological immobilization such that N recoveries in shoots, roots and leachates were reduced. Approximately 20% of the N present in Protox (a material derived from activated sewage sludge, processed to reduce the heavy metal content to minimal levels) appeared to be resistant to microbial degradation and was unavailable to the plants. Therefore, the growth response of lettuce was slightly reduced with Protox compared to the other materials at similar rates of incorporation. The organic materials did not contribute NO3−N to the plant and small NO3−N concentrations in petioles were derived from the water used for irrigation. However, NO3−N levels in plants receiving inorganic ammonium nitrate were initially high but progressively declined as the fertilizer NO3−N became depleted.
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    Biological control of sheath-blight of rice in india with antagonistic bacteria (1989)
    Springer
    Plant and soil 119 (1989), S. 325-330 
    Details
    ISSN: 1573-5036
    Keywords: antibiosis ; bacterization ; biological control ; rice ; sheath-blight
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Strains of fluorescent and nonfluorescent bacteria that were isolated from rice rhizospheres of Southern India and showed antagonism towardsRhizoctonia solani were evaluated for biological control of rice sheath-blight (ShB). Efficient strains of bacteria inhibited mycelial growth ofR. solani, affected sclerotial viabilityin vitro and protected IR 20 and TKM 9 rice seedlings from infection byR. solani in greenhouse tests. Pretreatment of sclerotia in bacterial suspensions resulted in reductions in ShB lesion sizes up to 31 to 44% in IR20 and 58 to 74% in TKM 9 rice. In field plots, IR 50 and TKM 9 rice plants raised from bacterized seeds had 65 to 72% less ShB than those plants from untreated seeds.
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    URL: http://dx.doi.org/10.1007/BF02370425
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    Variability of C, N and P content of a tropical semiarid soil as affected by soil genesis, erosion and land clearing (1989)
    Springer
    Plant and soil 119 (1989), S. 337-341 
    Details
    ISSN: 1573-5036
    Keywords: carbon ; erosion ; land clearing ; nitrogen ; noncalcic brown soils ; phosphorus ; spatial variability ; xerosols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Several transects of topsoil samples were taken immediately after land clearing and one year later from a savannah soil in the semiarid NE of Brazil. Natural spatial variability of key fertility indicators (C, N, P) was large with coefficients of variation 〉50%. This variability was related to heterogeneity of the soil parent material, and to relative slope position which affected deposition and removal of erodible materials. The distribution of gravel and different particle size fractions was an indicator of the variability as related to soil formation and erosional resorting. One year after the site was cleared and planted to trees, the decrease in C, N and resin-extractable P was in the same range as the initial spatial variability. Treatment effects were therefore difficult to observe but became more obvious when regression analysis on soil textural components was used to reduce data variability.
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    Genetic improvement of yield of nitrogen of Lolium perenne pastures (1989)
    Springer
    Euphytica 43 (1989), S. 259-262 
    Details
    ISSN: 1573-5060
    Keywords: Lolium perenne ; perennial ryegrass ; nitrogen ; protein, yield
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Four varieties of Lolium perenne with similar flowering dates bred over a 30 year period were grown in an orthogonal plot trial with two contrasting harvesting frequencies and three levels of fertiliser (0.2, 0.4 and 0.6 t/ha of N annually). In the second harvest year, the nitrogen (N) content of herbage at each harvest was determined and the yields of N calculated. The newest variety (Ba 10761) gave a 20% higher mean annual yield of N than the oldest (S.321). The influence of variety in increasing the ratio of N recovered: N applied was as great or greater than the influence of harvesting frequency or level of applied N. There were small differences between varieties in N content (%N), N content being inversely related to N yield.
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    Role of weeds in the management of nitrogen in a young Pinus radiata plantation (1989)
    Springer
    New forests 3 (1989), S. 203-224 
    Details
    ISSN: 1573-5095
    Keywords: weeds ; Pinus radiata ; competition ; nitrogen ; water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Pinus radiata trees were grown on a podzolized sandy soil at a second rotation site under the following treatments: total weed control, total weed control plus ammonium nitrate, strip weed control and no weed control. During the first two summers after planting the differences in needle water potential between trees under no, strip or total weed control were very small. Despite similar rates of net N-mineralization in strip and total weed control treatments, which averaged 64 kg ha−1 yr−1 in the 0–15 cm soil depth, weeds in the strip weed control treatment reduced soil mineral-N concentrations by 50–80%, leaching of N by the end of the first growing season by 45%, foliar-N concentrations by 4–14% and stem biomass at 20 months after planting by 46%. Although N-uptake by above-ground vegetation (trees plus weeds) was 49% higher in the strip weed control treatment, the amount of N apportioned to trees during the first 20 months after planting was reduced from 15.5 to 9.0 kg ha−1. These effects of weeds were even more pronounced in the no weed control treatment. Since weeds had little effect on the needle water potential of trees and the annual rates of N-mineralization, but adversely affected N-uptake by trees, results indicate that weeds directly competed with trees for N, and thereby aggravated N-deficiency in trees. Application of ammonium nitrate after complete weed control increased foliar-N concentrations, and N-uptake and growth of trees, but also induced severe stem deformation.
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    Carbon and nitrogen dynamics along the decay continuum: Plant litter to soil organic matter (1989)
    Springer
    Plant and soil 115 (1989), S. 189-198 
    Details
    ISSN: 1573-5036
    Keywords: carbon ; cellulose ; decomposition ; δ13C ; δ15N ; lignin ; nitrogen ; stable isotopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Decay processes in an ecosystem can be thought of as a continuum beginning with the input of plant litter and leading to the formation of soil organic matter. As an example of this continuum, we review a 77-month study of the decay of red pine (Pinus resinosa Ait.) needle litter. We tracked the changes in C chemistry and the N pool in red pine (Pinus resinosa Ait.) needle litter during the 77-month period using standard chemical techniques and stable isotope, analyses of C and N. Mass loss is best described by a two-phase model: an initial phase of constant mass loss and a phase of very slow loss dominated by degradation of ‘lignocellulose’ (acid soluble sugars plus acid insoluble C compounds). As the decaying litter enters the second phase, the ratio of lignin to lignin and cellulose (the lignocellulose index, LCI) approaches 0.7. Thereafter, the LCI increases only slightly throughout the decay continuum indicating that acid insoluble materials (‘lignin’) dominate decay in the latter part of the continuum. Nitrogen dynamics are also best described by a two-phase model: a phase of N net immobilization followed by a phase of N net mineralization. Small changes in C and N isotopic composition were observed during litter decay. Larger changes were observed with depth in the soil profile. An understanding of factors that control ‘lignin’ degradation is key to predicting the patterns of mass loss and N dynamics late in decay. The hypothesis that labile C is needed for ‘lignin’ degradation must be evaluated and the sources of this C must be identified. Also, the hypothesis that the availability of inorganic N slows ‘lignin’ decay must be evaluated in soil systems.
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    Cycling of nutrients from dying roots to living plants, including the role of mycorrhizas (1989)
    Springer
    Plant and soil 115 (1989), S. 211-215 
    Details
    ISSN: 1573-5036
    Keywords: Lolium perenne ; mycorrhiza ; nitrogen ; nutrient cycling ; phosphorus ; roots
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This paper presents information about the release of nitrogen and phosphorus from dying grass roots and the capture of phosphorus by other, living plants. We have paid particular attention to the part played by mycorrhizas in this phosphorus capture, and the possible importance of mycorrhizal links between dying and living roots. WhenLolium perenne plants were grown with ample nutrients and their roots then detached and buried in soil, about half the nitrogen and two-thirds of the phosphorus was lost in three weeks, but only one-fifth of the dry weight. The C:N and C:P ratios suggest that microbial growth in the roots would at first be C-limited but would become N- and P-limited within three weeks. Rapid transfer of32P can occur from dying roots to those of a living plant if the two root systems are intermingled. The amount transferred was substantially increased in two species-combinations that are known to form mycorrhizal links between their root systems. In contrast, in a species-combination where only the living (‘receiver’) plant could become mycorrhizal no significant increase of32P transfer occurred. This evidence, although far from conclusive, suggests that mycorrhizal links between dying and living roots can contribute to nutrient cycling. This research indicates a major difference in nutrient cycling processes between perennial and annual crops.
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    URL: http://dx.doi.org/10.1007/BF02202589
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    Perspectives on measurement of denitrification in the field including recommended protocols for acetylene based methods (1989)
    Springer
    Plant and soil 115 (1989), S. 261-284 
    Details
    ISSN: 1573-5036
    Keywords: acetylene inhibition ; denitrifiers ; geostatistics ; kriging ; nitrogen ; nitrogen-15 ; nutrient cycling ; soil cores ; terrestrial ecosystems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Of the biogeochemical processes, denitrification has perhaps been the most difficult to study in the field because of the inability to measure the product of the process. The last decade of research, however, has provided both acetylene and15N based methods as well as undisturbed soil core andin situ soil cover sampling approaches to implementing these methods. All of these methods, if used appropriately, give comparable results. Thus, we now have several methods, each with advantages for particular sites or objectives, that accurately measure denitrification in nature. Because of the general usefulness of the acetylene methods, updated protocols for the following three methods are given: gas-phase recirculation soil cores; static soil cores; and the denitrifying enzyme assay also known as the phase 1 assay. Despite the availability of these and other methods, denitrification budgets remain difficult to accurately establish in most environments because of the high spatial and temporal variability inherent in denitrification. Appropriate analysis of those data includes a distribution analysis of the data, and if highly skewed as is typically the case, the most accurate method to estimate the mean and the population variance is the UMVUE method (uniformly minimum variance unbiased estimator). Geostatistical methods have also been employed to improve spatial and temporal estimates of denitrification. These have occasionally been successful for spatial analysis but in the attempt described here for temporal analysis the approach was not useful. Discussions of the importance of denitrification have always focused on quantifying the process and whether particular measured quantities are judged to be a significant amount of nitrogen. A second line of evidence discussed here is the extant genetic record that results from natural selection. These analysis lead to the conclusion that strong selection for denitrification must currently be occurring, which implies that the process is of general significance in soils.
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    The role of vibrationally excited nitrogen in the ionosphere (1988)
    Springer
    Pure and applied geophysics 127 (1988), S. 529-544 
    Details
    ISSN: 1420-9136
    Keywords: Ionosphere ; nitrogen ; vibrational temperatures ; N2 and CO2 and populations of N2 and CO2 in the D, E and F regions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Theoretical and experimental aspects of the production, transformation, diffusion and loss of N2 in the upper atmosphere are considered. The N2-CO2 near-resonant system in theD andE regions is taken into account. We describe our understanding of the methods necessary to find the vibrational populations of N2 and CO2 (asymmetric mode of CO2). The calculations of the vibrational temperatures in theD, E, andF regions for the mid-latitude ionosphere and an aurora are presented. The connection between the excited species and the 4.26-μm radiation intensities is considered. The models for the rate coefficient of the reaction of O+ with N2 and the electron density decrease resulting from N2 in the F region are discussed.
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    URL: http://dx.doi.org/10.1007/BF00879824
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    Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica III. Cycles of organic matter and nutrients (1988)
    Springer
    Agroforestry systems 6 (1988), S. 49-62 
    Details
    ISSN: 1572-9680
    Keywords: Theobroma cacao ; shade trees ; Erythrina poeppigiana ; Cordia alliodora ; modelling ; organic matter ; nitrogen ; phosphorus ; potassium ; calcium ; magnesium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Models for cycles for organic matter and nutrients element (N, P, K, Ca and Mg) are presented for the agroforestry systems of cacao (Theobroma cacao) withCordia alliodora orErythrina poeppigiana in Turrialba, Costa Rica. For the models, system reserves (soil, humus, vegetation divided into leaves, branches, stems, fine roots, fruits) and transference between compartments (production and decomposition of litter residues) inputs (fertilizer, rainfall) and outputs (harvests) of the system are considered. The implications of the models are discussed in detail. Aspects of net primary production in the systems studied are considered. N fixation is calculated on the basis of balances. Analysis of soil water showed high variations that coincided with rainfall patterns and pruning of theE. poeppigiana.
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    Effects of nitrogen fertilizer and weed control on nutritive quality of carrots (Daucus carota L.) (1988)
    Springer
    Plant foods for human nutrition 38 (1988), S. 67-73 
    Details
    ISSN: 1573-9104
    Keywords: carrots ; carotene ; T.S.S. ; herbicides ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The nutritive quality of carrots, obtained from different herbicide-treated plots and under different levels of nitrogen application ranging from zero to 80kg nitrogen/ha, was compared. There were significant differences in carotene content, T.S.S. (total soluble solids) and organolptic characteristics under the influence of different treatments. The maximum carotene content, T.S.S. and organoleptic characteristics were observed with the application of 80 kg. nitrogen/ha and fluchloralin herbicide at 0.90 and 1.20 kg/ha.
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    Variation of the amino acid scores and of the nitrogen-to-protein conversion factors in barley grain as a function of nitrogen content as compared with wheat and rye (1988)
    Springer
    Plant foods for human nutrition 38 (1988), S. 175-188 
    Details
    ISSN: 1573-9104
    Keywords: barley ; Triticeae ; grain ; amino acid composition ; nitrogen ; chemical score
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Barley grains (9 samples from 7 cultivars) with nitrogen contents (N) ranging from 1.45 to 4.01% of dry matter were analysed for their amino acid (AA) composition with high accuracy from six different hydrolysates per sample. AA levels in grain increased as linear functions ofN with correlation coefficients close to unity. A comparison with literature data confirmed that the AA composition of any grain sample of normal barley can be predicted from itsN for all phenotypes and genotypes. AAs in grain protein changed as hyperbolic functions ofN which increased for Phe, Pro and Glx but more or less strongly decreased for the other AAs. By plotting AA scores againstN, barley proteins were shown to be always richer than wheat and rye in Val and Phe + Tyr; sometimes richer than both other species forN〈2 (Lys); 2.2 (Leu and Ile); 3.4 (Thr); sometimes intermediate to wheat and rye above the latterN values. They were also intermediate in sulphur AAs forN〈1.9 and drastically poorer forN〉1.9. However, they were richer than both other species in Trp forN〉1.6. The hyperbolic variations of non-protein nitrogen and nitrogen-to-protein conversion factors were determined as a function ofN and also compared with those of wheat and rye.
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    Release in Manitoba, Canada oftownesilitus bicolor [HYM.: Braconidae], an European parasite ofPhyllotreta spp. [Col.: Chrysomelidae] (1988)
    Springer
    BioControl 33 (1988), S. 25-32 
    Details
    ISSN: 1573-8248
    Keywords: Townesilitus bicolor ; Phyllotreta ; euphorine ; biological control ; Townesilitus bicolor ; Phyllotreta ; euphorine ; lutte biologique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Townesilitus bicolor (Wesmael), parasite de quelques espèces dePhyllotreta ravageurs des crucifères en Europe, a été lâché au Manitoba de 1978 à 1983 en vue de réduire les populations dePhyllotreta crucifera (Goeze) et deP. striolata (Fab.). Les lâchers totalisainet 1936 adultes deT. bicolor et environ 2636Phyllotreta récltés au Manitoba et parasité et laboratoire. On n'a observé aucune preuve d'établissement jusqu'en 1985, ni dans l'un ni dans l'autre des 2 lieux de lâcher. Le petit nombre de parasites lâchés et la dispersion de la population hôte 2 fois par an ont réduit la probabilité d'établissement du parasite et de sa détection.
    Notes: Abstract Townesilitus bicolor (Wesmael), a parasite of some crucifer-infesting species ofPhyllotreta in Europe, was released in Manitoba Canada in 1978–83, in an attempt to reduce populations ofPhyllotreta cruciferae (Goeze) andP. striolata (Fab.). Releases totalled 1936 adults ofT. bicolor and approximately 2639Phyllotreta collected in Manitoba and parasitized in the laboratory. No evidence of establishment was found up to 1985 at either of the 2 release sites. The small numbers of parasite released, and dispersal of the host population twice each year, have reduced the probability of the parasite becoming established and of establishment being detected.
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    Control ofThrips tabaci [Thysanoptera: Thripidae] on glasshouse cucumber using large introductions of predatory mitesAmblyseius barkeri [Acarina: Phytoseiidae] (1988)
    Springer
    BioControl 33 (1988), S. 33-42 
    Details
    ISSN: 1573-8248
    Keywords: Thrips tabaci ; Amblyseius barkeri ; glasshouse ; biological control ; cucumber ; Phytoseiidae ; Thrips tabaci ; Amblyseius barkeri ; serre ; lutte biologique ; concombre ; Phytoseiidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé L'acarien phytoseïdeAmblyseius barkeri (Hughes) (=Amblyseius mckenziei Sch. & Pr.) a été employé pour réduire les populations deThirps tabaci Lind. dans 7 serres commerciales de concombres (d'une superficie totale de 5780 m2). Des acariens prédateurs ont été introduits 3–4 fois à raison de densités variant de 40 à 300/m2 à chaque lâcher. Dans 6 et 7 serres on a obtenu le maintien satisfaisant des populations de thrips pendant la saison de croissance. Les densités de thrips ont été limitées à 15 ou moins par feuille. Dans une serre on a constaté des dommages aux fruits à partir d'une densité de 25 thrips par feuille, mais la population de thrips a été réduite rapidement et s'est maintenue à des densités peu élevées pendant les 3 mois suivants.
    Notes: Abstract The phytoseiid miteAmblyseius barkeri (Hughes) (=Amblyseius mckenziei Sch. & Pr.) was used for biological control ofThrips tabaci Lind. in 7 commercial glasshouses with cucumber (a total of 5780 m2). Predatory mites were introduced 3–4 times in densities ranging from 40 to 300/m2 at each release. In 6 of the 7 glasshouses, control of thrips was satisfactory throughout the growing season. Thrips densities were kept below 15 individuals per leaf. In 1 glasshouse, thrips damage was seen on the fruits at densities of 25 thrips per leaf, but the thrips population was quickly reduced and remained at low densities for the next 3 months.
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    Dicyphus tamaninii as a beneficial insect and pest in tomato crops in Catalonia, Spain (1988)
    Springer
    BioControl 33 (1988), S. 219-228 
    Details
    ISSN: 1573-8248
    Keywords: Dicyphus tamaninii ; Trialeurodes vaporariorum ; biological control ; vegetable crops ; tomato ; Dicyphus tamaninii ; Trialeurodes vaporariorum ; lutte biologique ; cultures légumières ; tomate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé En Catalogne, la punaise mirideDicyphus tamaninii Wagner est une espèce commune dans les cultures non traitées avec des insecticides. Afin d'étudier ses habitudes alimentaires nous avons mis en place à la Station Expérimentale de Cabrils des parcelles expérimentales de tomate avec ou sans traitements insecticides en 1983, 1984 et 1985. Les résultats indiquent que les populations deTrialeurodes vaporariorum Westwood sont grandement affectées par la punaise quand on n'applique pas d'insecticides ou quand le nombre de traitement est réduit. Cependant, la punaise cause de gros dégâts sur les tomates dans les parcelles non traitées, où l'on enregistre un grand nombre de punaises et peu d'aleurodes. La tomate est préférée, semble-t-il, uniquement lorsque la population d'aleurode est excessivement basse. Ces résultats concordent avec ceux obtenus d'une expérience avec des cages où l'exclusion de la punaise causa des proliférations inacceptables de l'aleurode.
    Notes: Abstract The mirid bugDicyphus tamaninii Wagner, is common in Catalonia in vegetable crops which have not been sprayed with insecticide. To study the feeding habits of this bug in tomato crops, several treated and untreated tomato plots were set up at Cabrils Experimental Station (North of Barcelona) during 1983, 1984 and 1985. The results indicate thatTrialeurodes vaporariorum Westwood populations are greatly affected by the mirid bug when no, or only a few, insecticide sprays are applied. However, the bug heavily damaged tomato fruits in unsprayed plots, where bug numbers were high and whitefly numbers low. It seems that tomato fruit is only preferred when whitefly numbers are extremely low. Similar results were obtained in 1984 in a preliminary experiment using cages to exclude the bug.
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    Prey selectivity inEuseius tularensis [Acari: Phytoseiidae] (1988)
    Springer
    BioControl 33 (1988), S. 281-287 
    Details
    ISSN: 1573-8248
    Keywords: prey selectivity ; preference ; Phytoseiidae ; biological control ; sélection des proies ; préférence ; Phytoseiidae ; lutte biologique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé L'étude porte sur les réactions du prédateur facultatifEuseius tularensis Congdon à l'égard du pollen et de différentes proies potentielles. A la suite d'une période d'isolement sans nourriture de 16 heures, des femelles de cet acarien sont observées en présence de l'un des aliments potentiels suivants: pollen deMalephora crocea (Jacquin) Schwantes; 2e stade larvaire deScirtothrips citri (Moulton); protonymphes, deutonymphes et mâles deTetranychus pacificus McGregor et dePanonychus citri (McGregor); larves deEuseius hibisci (Chant) et deE. tularensis. Les réponses du prédateur sont comparées, en se basant sur la proportion de rencontres qui aboutissent à une consommation. Cette proportion est la plus élevée lors de la mise en présence de pollen, elle est suivie par cell deS. citri et celle deT. pacificus. La consommation est la plus faible en présence de larves deP. citri et de larves d'Euseius spp. Lorsque des larves deS. citri sont présentées pour la 2e fois, 1 à 2 heures après la première capture, la consommation s'accroît et atteint un niveau comparable à celui qui est observé avec du pollen. Ces résultats font penser queE. tularensis est un agent de lutte biologique plus efficace contreS. citri que contreP. citri.
    Notes: Abstract Differences in responsiveness to potential prey and pollen were tested in the facultative predator,Euseius tularensis Congdon. Following isolation without food for 16 h, adult female mites were observed with one of the following potential foods: pollen ofMalephora crocea (Jacquin) Schwantes,Scirtothrips citri (Moulton) 2nd instar larvae,Tetranychus pacificus McGregor nymphs and ♂,Panonychus citri (McGregor) nymphs and ♂,E. hibisci (Chant) larvae, andE. tularensis larvae. Responses were compared using the proportion of encounters that resulted in consumption. This proportion was highest when pollen was encountered, followed byS. citri andT. pacificus. Consumption was much lower in response toP. citri and congeneric larvae. WhenS. citri larvae were encountered a 2nd time, 1 to 2 h after the initial capture and consumption, responsiveness increased to a level equal to the response observed with pollen. These results suggest thatE. tularensis is a more effective biological control agent of citrus thrips (S. citri) than of citrus red mite (P. citri).
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    Selection of nuclear polyhedrosis viruses as biological control agents ofSpodoptera exigua [Lep.: Noctuidae] (1988)
    Springer
    BioControl 33 (1988), S. 299-308 
    Details
    ISSN: 1573-8248
    Keywords: Spodoptera exigua ; nuclear polyhedrosis virus ; biological control ; identification ; biological activity ; Spodoptera exigua ; Virus à polyèdres nucléaires ; lutte biologique ; identification ; activité biologique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé La virulence de 5 virus à polyèdres nucléaires à capside multiple (MNPV) contre les chenilles deSpodoptera exigua a été comparée. Trois NPV ont été isolés de chenilles mortes, trouvées dans des serres aux Pays-Bas. A partir des analyses de DNA par des enzymes de restriction il est conclu que ces 3 NPV sont apparentés aux MNPV deMamestra brassicae et sont nommés MbMNPV-NL80, MbMNPV-NL82 et MbNPV-NL83. Ces MNPVs ne sont pas apparentés au MNPV d'Autographa california (AcMNPV), ni à celui deS. exigua (SeMNPV). SeMNPV est environ 5 fois plus virulent contre les chenilles du 2e stade larvaire deS. exigua que les autres MNPV qui ont des activité biologiques comparables entre elles. Les DL-50 de SeMNPV, AcMNPV, MbMNPV-NL80, NL82 et NL83 sont 3, 18, 26, 14 et 17 polyèdres, respectivement. On en conclut que le SeMNPV est le meilleur candidat pour l'utilisation dans un programme de lutte biologique contreS. exigua dans des serres aux Pays-Bas.
    Notes: Abstract The virulence of 5 nuclear polyhedrosis viruses infectious for larvae of beet armyworm,Spodoptera exigua, was studied and their potential as biological control agents of this accidentally introduced pest in Dutch greenhouse crops is discussed. Three of the virus isolates were collected from deceased beet armyworm larvae found in Dutch greenhouses. Based on restriction endonuclease patterns of their DNA they appeared to be closely related toMamestra brassicae nuclear polyhedrosis virus (MbMNPV) and therefore were named MbMNPV-NL80, MbMNPV-NL82 and MbMNPV-NL83. These isolates were not related toAutographa californica MNPV (AcMNPV) or toSpodoptera exigua MNPV (SeMNPV), both originating from the USA. Comparison of the oiological activity of these 5 isolates showed that the SeMNPV was more virulent against beet armyworm than the other isolates. There was no significant difference in virulence between MbMNPV-NL80, NL82, NL83 and AcMNPV forS. exigua. The LD-50 values of the 5 isolates for 2nd instar larvae were 3, 26, 14, 17 and 18 polyhedra, respectively. Despite compensating qualities of the other MNPVs, such as a broader host range and potential production in alternate hosts or cell-lines, SeMNPV is considered to be the most suitable candidate as biological control agent of beet armyworm.
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    Studies on the oviposition and longevity ofIlione albiseta [Dipt.: Sciomyzidae] — Potential biological control agent of liver fluke (1988)
    Springer
    BioControl 33 (1988), S. 387-395 
    Details
    ISSN: 1573-8248
    Keywords: Ilione albiseta ; Diptera ; Sciomyzidae ; temperature ; Lymnaea truncatula ; biological control ; Ilione albiseta ; Diptera ; Sciomyzidae ; température ; Lymnaea truncatula ; lutte biologique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Rémumé L'effet de 5 températures constantes (10, 14, 17, 20 et 23 °C) a été étudié sur l'oviposition et la longévité d'Ilione albiseta. La plupart des œufs furent ponndus entre 14 et 17 °C et la période d'oviposition moyenne décroissait progressivement au-dessus et au-dessous de 14 °C. Il n'y avait pas de différence significative entre les taux d'oviposition et les périodes de préoviposition à chaque température constante, mais le nombre moyen de jours entre la ponte pour chaque femelle était significativement plus grand à 10 °C qu'à 17, 20 et 23 °C et plus grand à 14 °C. qu' à 23 °C. Les adultes infertiles allait de 9,2 % à 23 °C jusqu'à 17,9% à 20 °C et ces œufs avaient tendance à être pondus au commencement comme à la fin de chaque période d'oviposition. Une corrélation possible entre le sex-ratio de l'adulte éclos et la température est discutée également.
    Notes: Abstract The effect of 5 constant temperatures (10, 14, 17, 20 and 23°C) on the oviposition and longevity ofIlione albiseta was investigated. Most eggs were laid at 14–17°C and mean oviposition period declined progressively above and below 14°C. There was no significant difference between oviposition rates or preoviposition periods at each constant temperature, but the mean number of days between egg laying for each female was significantly greater at 10 °C than at 17, 20 and 23 °C than at 20 °C. The percentage of infertile eggs laid ranged from 9.2% at 23 °C to 17.9 % at 20 °C and these eggs tended to be laid at the beginning and end of each oviposition period. A possible association between sex ratio of the emergent adult and temperature is also discussed.
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    Mass production and utilization ofTrichogramma: 10. Control of the codling mothCydia pomonella and the summer fruit tortrix mothAdoxophyes orana [Lep.: Tortricidae] (1988)
    Springer
    BioControl 33 (1988), S. 413-420 
    Details
    ISSN: 1573-8248
    Keywords: Trichogramma ; codling moth ; summer fruit tortrix moth ; biological control ; apple orchards ; Trichogramma ; Apfelwickler ; Apfelschalenwickler ; biologische Schädlingsbekämpfung ; Apfelanlagen ; Trichogramma ; Carpocapse ; tordeuse des fruits ; lutte biologique ; vergers de pommiers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Zusammenfassung Die Bekämpfung des ApfelwicklersCydia pomonella L. sowie des ApfelschalenwicklersAdoxophyes orana F.R. durch Freilassungen vonTrichogramma dendrolimi, T. embryophagum. T. sp. Stamm 45 undT. sp. Stamm 48 wurde zwischen 1984 und 1986 in vier Feldversuchen erprobt. Bei vier bis sechsTrichogramma-Behandlungen zwischen Juni und August (in Abhängigkeit von der Temperatur) gelangten pro Baum jeweils ca. 400 Parasiten bei Pillarbäumen und ca. 9 000 Parasiten bei Rundkronen zum Einsatz. Auf diese Weise waren in den Parzellen ständig aktive Parasiten vorhanden. Bei der Auswertung wurden 3 000 bis 10 000 Früchte pro Parzelle untersucht. T. dendrolimi reduzierte den Befall vonC. pomonella um 61,35%; den Befall vonA. orana um 72,85%.T. embryophagum verminderte den Befall vonC. pomonella um 50.06% sowie den Schaden durchA. orana um 50,80%.Trichogramma Stamm 45 führte zu Befallsverminderungen beiC. pomonella von 41,6% und beiA. orana von 87,9%.Trichogramma Stamm 48 konnte den Befall beiC. pomonella um 57,2% und den vonA. orana um 51,2% verringern. Durch die Freilassungen vonT. dendrolimi konnte in diesen Feldversuchen der Befall durchC. pomonella undA. orana um 67,1% reduziert werden. Diese Ergebnisse sind wirtschaftlich von Interesse. Die praktische Anwendung vonT. dendrolimi gegen Wicklerarten im Apfelanbau wird empfohlen.
    Abstract: Résumé L'efficacité deTrichogramma dendrolimi, Trichogramma embryophagum, Trichogramma sp. souche 45 etTrichogramma sp. souche 48 pour lutter contre le CarpocapseCydia pomonella L. et la tordeuse des fruitsAdoxophyes orana F.R. a été expérimentée dans quatre essais de plein champ. Quatre à six traitements par Trichogrammes (dépendant de la température) à raison de 400 individus/arbre (au centre) à 9 000 parasites à la périphérie du faîte ont été réalisés entre juin et août afin d'assurer la présence continue deTrichogramma dans les parcelles. La surveillance a été réalisée par l'examen de 3 000 à 10 000 pommes par parcelle. T. dendrolimi réduit les dégâts du Carpocapse de 61,35% et d'A. orana de 72,85%.T. embryophagum réduit les dégâts deC. pomonella de 50,06% et d'A. orana de 50,08%. La souche 45 deTrichogramma réduit les dégâts deC. pomonella de 41,6% et d'A. orana de 87,9%, la souche 48 deTrichogramma de 57,2% et de 51,2 respectivement. La réduction de 67,1% du nombre de pommes endommagées parC. pomonella etA. orana obtenue par les lâchers inondatifs deT. dendrolimi dans ces expériences est considérée comme significative économiquement et l'emploi de cette espèce peut être recommandé dans la pratique.
    Notes: Abstract The effectiveness ofTrichogramma dendrolimi, Trichogramma embryophagum, Trichogramma sp. strain 45 andTrichogramma sp. strain 48 to control the codling mothCydia pomonella L. and the summer fruit tortrix mothAdoxophyes orana F.R. was tested in 4 field trials (1984–1986). Four to sixTrichogramma treatments (depending on the temperature) each at 400 (pillar trees) to 9,000 (round tops) parasites per tree were carried out between June and August to insure the continuous presence ofTrichogramma in the plots. The monitoring was done by examining 3,000 to 10,000 apple fruits per plot. T. dendrolimi reduced the damage ofC. pomonella by 61.35%, ofA. orana by 72.85%.T. embryophagum reduced the damage ofC. pomonella by 50.06%, ofA. orana by 50.8%.Trichogramma strain 45 reduced the damage ofC. pomonella by 41.6% and ofA. orana by 87.9%,Trichogramma strain 48 by 57.2% and 51.2% respectively. The reduction of 67.1% in the number of apple fruits damaged byC. pomonella andA. orana obtained by the inundative releases ofT. dendrolimi in these experiments is considered economically and the use of this species in practice is recommended.
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    Nutrient uptake by barley roots under field conditions (1988)
    Springer
    Plant and soil 109 (1988), S. 171-179 
    Details
    ISSN: 1573-5036
    Keywords: Black Solod ; inflow ; magnesium ; nitrogen ; phosphorus ; potassium ; root efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field study with barley was conducted in 1984 and 1985 to provide data on uptake rates of N, P, K and Mg and their variation as the growing season progressed. Two varieties were grown: Galt in 1984 and Otal in 1985. Soil fertility was maintained at or near optimum conditions. Samples were obtained approximately every 10 days for shoot dry weight, nutrient content and root length measurements. The approximate method (Williams, 1948) traditionally used for calculating uptake rates was found to be invalid for most of the nutrients studied. The method used for measuring uptake rates was the functional approach proposed by Hunt (1973). Inflow,i.e. uptake rate per unit root length, of plant nutrients, decreased with time. However, maximum uptake rates measured in kg ha−1d−1 occurred at about 50 days from sowing because of increasing root length density with time. Inflow or uptake rates were low in 1985 because of moisture deficiency, and grain yield (0.89 t ha−1) was severely depressed. This study demonstrated that Hunt's method is superior and more advantageous than the traditional, approximate method.
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    A contribution to the knowledge of nematophagous species of Verticillium (1988)
    Springer
    European journal of plant pathology 94 (1988), S. 123-148 
    Details
    ISSN: 1573-8469
    Keywords: plant-parasitic nematodes ; cyst nematodes ; endoparasites ; biological control ; Hyphomycetes ; taxonomy ; distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Samenvatting Negen nematofage soorten en twee variëteiten vanVerticillium (Verticillium sectieProstrata), die óf als parasieten van vrijlevende aaltjes óf als parasieten van cysten en eieren optreden, worden gereviseerd en er wordt een determinatiesleutel van gepresenteerd.V. catenulatum wordt gereduceerd tot een variëteit vanV chlamydosporium. Een hierop lijkende schimmel wordt onderscheiden als.V. suchlasporium n.sp. (incl. een variëteitcatenatum. Spicaria coccospora Drechsler wordt naarVerticillium overgebracht. Alle soorten werden in reincultuur onderzocht. Voor iedere soort worden oecologische gegevens vermeld.
    Notes: Abstract Nine nematophagous species and two varieties ofVerticillium (Verticillium sect.Prostrata), occurring either as parasites of free-living nematodes or as parasites of cysts and eggs, are revised and keyed out.V. catenulatum is reduced to a variety ofV. chlamydosporium A similar fungus is distinguished asV. suchlasporium n. sp. (including a var.catenatum). Spicaria coccospora Drechsler is transferred toVerticillium. All species have been studied in pure culture. Ecological data are reviewed for each species.
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    Inactivation of sclerotia of Rhizoctonia solani on potato tubers by Verticillium biguttatum, a soil-borne mycoparasite (1988)
    Springer
    European journal of plant pathology 94 (1988), S. 225-231 
    Details
    ISSN: 1573-8469
    Keywords: biological control ; black scurf ; certification of seed tubers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Samenvatting In proeven in het laboratorium en in de praktijk werden sclerotiën vanRhizoctonia solani (lakschurft) gedood door met lakschurft bezette knollen te beënten met sporen vanVerticillium biguttatum. Sclerotiën op kort tevoren gerooide knollen worden bijna volledig gedood in 6–8 weken, als aan de volgende voorwaarden wordt voldaan. (1) Er moet een direct contact zijn tussen de sclerotiën en de sporen vanV. biguttatum. De sclerotiën op de knollen moeten dus vrij zijn van aanhangende grond. (2) De temperatuur moet gedurende de bewaring tenminste 15 °C zijn en gedurende de eerste weken liever 20 °C of dicht hierbij. Dit is in augustus, als de poters in de bewaarplaats worden gebracht, meestal wel het geval. (3) De relatieve vochtigheid van de lucht tussen de knollen moet 100% zijn. Dit is meestal het geval in een hoop pas gerooide, jonge knollen. Om de bovenste laag van 40–50 cm niet te droog te laten worden kan het oppervlak afgedekt worden met een laag grove jute zakken. Door borstelen kunnen dode sclerotiën soms grotendeels worden verwijderd; dit is nodig voor de keuring omdat dode en levende sclerotiën op het oog niet te onderscheiden zijn. Voor de verwijdering van dode sclerotiën wordt naar een betere methode gezocht.
    Notes: Abstract Experiments in the laboratory and on farms with potato tubers in storage are described in which sclerotia ofRhizoctonia solani were inactivated after inoculation of infected tubers with a suspension of conidia and hyphal fragments ofVerticillium biguttatum. Sclerotia on freshly harvested tubers can be killed in a period of six to eight weeks, provided that (1) a direct contact between sclerotia and conidia ofV. biguttatum is obtained, (2) the temperature during the storage period is at least 15 °C, but preferably closer to 20 °C during the first weeks, and (3) the relative humidity of the air between the tubers is at least 99%. Seed tubers are only certified as export quality if the infection withR. solani, visible as sclerotia on the tubers, is assessed as below a specified incidence. To restore the economical value of tubers with many sclerotia, living sclerotia can be inactivated byV. biguttatum. However, also dead sclerotia have to be removed, as dead and living sclerotia cannot be distinguished visually by inspectors. A satisfactory way to remove dead sclerotia from tubers has not yet been found.
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    Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica II. Cacao and wood production, litter production and decomposition (1988)
    Springer
    Agroforestry systems 6 (1988), S. 37-48 
    Details
    ISSN: 1572-9680
    Keywords: Theobroma cacao ; shade trees ; Erythrina poeppigiana ; Cordia alliodora ; modelling ; organic matter ; nitrogen ; phosphorus ; potassium ; calcium ; magnesium ; litter production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract During 7 years (1979–1985) cacao harvests (beans and husks) have been recorded for the agroforestry systems ofTheobroma cacao underCordia alliodora andErythrina poeppigiana shade trees. The mean oven dry cacao yields were 626 and 712 kg.ha−1.a−1 cocoa beans underC. alliodora andE. poeppigiana respectively. Harvests have gradually increased over the years and the plantation has now reached maturity. Annual extraction of N, P, K, Ca and Mg in fruits, which is relatively small, was calculated on the basis of chemical analyses. The following average values were found (kg.ha−1.a−1): At the age of 8 years, theC. alliodora trees have reached 26.7 cm diameter (DBH) and 14.0 m in height. Mean annual growth (from age 5 to 7) is 14.6 m3.ha−1.a−1. Natural plant residue production has been measured for 4 years (Nov. 1981–Oct. 1985). UnderE. poeppigiana it has reached a value of 8.91 t.ha−1.a−1 and underC. alliodora 7.07 t.ha−1.a−1. The shade trees have contributed 57 and 47% respectively. Transference and decomposition rates are high and important in the nutrient cycles. The nutrient content of the litter was analysed and corresponding average yearly transfers were (kg.ha−1.a−1):
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    URL: http://dx.doi.org/10.1007/BF02344744
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    Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica III. Cycles of organic matter and nutrients (1988)
    Springer
    Agroforestry systems 6 (1988), S. 49-62 
    Details
    ISSN: 1572-9680
    Keywords: Theobroma cacao ; shade trees ; Erythrina poeppigiana ; Cordia alliodora ; modelling ; organic matter ; nitrogen ; phosphorus ; potassium ; calcium ; magnesium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Models for cycles for organic matter and nutrients element (N, P, K, Ca and Mg) are presented for the agroforestry systems of cacao (Theobroma cacao) withCordia alliodora orErythrina poeppigiana in Turrialba, Costa Rica. For the models, system reserves (soil, humus, vegetation divided into leaves, branches, stems, fine roots, fruits) and transference between compartments (production and decomposition of litter residues) inputs (fertilizer, rainfall) and outputs (harvests) of the system are considered. The implications of the models are discussed in detail. Aspects of net primary production in the systems studied are considered. N fixation is calculated on the basis of balances. Analysis of soil water showed high variations that coincided with rainfall patterns and pruning of theE. poeppigiana.
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    URL: http://dx.doi.org/10.1007/BF02220108
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    Modelling agroforestry systems of cacao (Theobroma cacao) with laurel (Cordia alliodora) and poro (Erythrina poeppigiana) in Costa Rica II. Cacao and wood production, litter production and decomposition (1988)
    Springer
    Agroforestry systems 6 (1988), S. 37-48 
    Details
    ISSN: 1572-9680
    Keywords: Theobroma cacao ; shade trees ; Erythrina poeppigiana ; Cordia alliodora ; modelling ; organic matter ; nitrogen ; phosphorus ; potassium ; calcium ; magnesium ; litter production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract During 7 years (1979–1985) cacao harvests (beans and husks) have been recorded for the agroforestry systems ofTheobroma cacao underCordia alliodora andErythrina poeppigiana shade trees. The mean oven dry cacao yields were 626 and 712 kg.ha−1.a−1 cocoa beans underC. alliodora andE. poeppigiana respectively. Harvests have gradually increased over the years and the plantation has now reached maturity. Annual extraction of N, P, K, Ca and Mg in fruits, which is relatively small, was calculated on the basis of chemical analyses. The following average values were found (kg.ha−1.a−1): At the age of 8 years, theC. alliodora trees have reached 26.7 cm diameter (DBH) and 14.0 m in height. Mean annual growth (from age 5 to 7) is 14.6 m3.ha−1.a−1. Natural plant residue production has been measured for 4 years (Nov. 1981–Oct. 1985). UnderE. poeppigiana it has reached a value of 8.91 t.ha−1.a−1 and underC. alliodora 7.07 t.ha−1.a−1. The shade trees have contributed 57 and 47% respectively. Transference and decomposition rates are high and important in the nutrient cycles. The nutrient content of the litter was analysed and corresponding average yearly transfers were (kg.ha−1.a−1):
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    Nitrogen and potassium requirement of pineapple in relation to irrigation in Nigeria (1988)
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    Nutrient cycling in agroecosystems 15 (1988), S. 203-210 
    Details
    ISSN: 1573-0867
    Keywords: irrigation ; pineapples ; nitrogen ; potassium ; yield ; Nigeria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The investigation studied the effect of fertilization with four nitrogen levels (0, 100, 150 and 200 kg/ha), four potassium levels (0, 100, 150 and 200 kg/ha) and four irrigation treatments (0, 3, 7 and 14-day interval) on the growth and yield of smooth Cayenne pineapples. Increasing irrigation frequency increased growth parameters of number of leaves, D-leaf length and days to 50% flowering. Fruit weight was highest at N = 150 kg/ha, K = 200 kg/ ha and irrigation once a week. Higher N levels (beyond 150 kg/ha) applied after the plant crop has been harvested did not further enhance yields of the ratoon crop. For K = 200 kg/ha potential and harvested yields were reduced in all irrigation treatments when N 〉 150 kg/ha.
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    URL: http://dx.doi.org/10.1007/BF01051342
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    Fertilizer requirement of rice-wheat and maize-wheat rotations on coarse-textured soils amended with farmyard manure (1988)
    Springer
    Nutrient cycling in agroecosystems 17 (1988), S. 153-164 
    Details
    ISSN: 1573-0867
    Keywords: farmyard manure ; maize ; nitrogen ; phosphorus ; rice ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Field experiments with rice-wheat rotation were conducted during five consecutive years on a coarse-textured low organic matter soil. By amending the soil with 12t FYM ha−1, the yield of wetland rice in the absence of fertilizers was increased by 32 per cent. Application of 80 kg N ha−1 as urea could increase the grain yield of rice equivalent to 120 kg N ha−1 on the unamended soil. Although the soil under test was low in Olsen's P, rice did not respond to the application of phosphorus on both amended and unamended soils. For producing equivalent grain yield, fertilizer requirement of maize grown on soils amended with 6 and 12 t FYM ha−1 could be reduced, respectively to 50 and 25 per cent of the dose recommended for unamended soil (120 kg N + 26.2 kg P + 25 kg K ha−1). Grain yield of wheat grown after rice on soils amended with FYM was significantly higher than that obtained on unamended soil. In contrast, grain yield of wheat which followed maize did not differ significantly on amended or unamended soils.
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    Productivity of nitrogen fertilized plantain in intercropping systems (1988)
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    Nutrient cycling in agroecosystems 18 (1988), S. 245-250 
    Details
    ISSN: 1573-0867
    Keywords: plantain ; intercropping systems ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The investigation evaluated the productivity of plantain intercropped with cassava, cocoyam and yam, fertilized annually with 0, 320 and 480 kg N ha−1 respectively. Yields from nitrogen fertilized intercrops were higher than those of unfertilized treatments. In plantain + cassava intercrop receiving 480 kg N ha−1 plantain growth was suppressed. Plantain intercropped with yam and fertilized with 320 kg N ha−1 matured early and produced better bunches than other treatments. Plantain + yam or cocoyam intercropping systems fertilized with 320 kg N ha−1 were recommended because of improved plantain establishment and increased combined crop yields.
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    Response surface analysis of the effects of seeding rates, N-rates and irrigation frequencies on durum wheat I. Grain yield and yield components (1988)
    Springer
    Nutrient cycling in agroecosystems 17 (1988), S. 197-218 
    Details
    ISSN: 1573-0867
    Keywords: Durum ; grain yield ; irrigation ; modoc ; nitrogen ; response surface model ; seeding rate ; Triticum turgidum ; yield components
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Interactive effects of nitrogen (N) rates, seeding (S) rates and irrigation frequencies on grain yield and yield components of durum wheat were studied for four years under field conditions at Tulelake, California. Each year the experiment was conducted using a split-plot design with 4 irrigation frequencies as main plots and combinations of 5 N-rates (0 to 360 kg/ha) and 5 S-rates (50 to 250 kg/ha) as subplot treatments replicated 4 times. A quadratic response surface model (RSM) was used to study the effects of these treatments on grain yield and yield components (tillers/area, kernel number/spike, kernel weight/spike and 100-seed weight). The RSM was very effective for analysis and data reduction for estimating the optimum combinations of N and S for maximizing the grain yield and yield components. The N utilization and uptake efficiency increased with each irrigation treatment and peaked at irrigation treatment C. Both N and uptake utilization efficiency decreased with each increment of N-rate. In most cases, the effect of irrigation was independent of N and S. One irrigation at tillering increased grain yield and yield components significantly over only a preplant irrigation. The response of additional irrigations were comparatively small and significant only in some cases. Both N and S had significant effects on grain yield and yield components, however, the response of N was larger than that of S. With increasing N-rate, grain yield and tiller number increased with the expected peak beyond 360kg N ha−1 but the increments beyond 180 kg N ha−1 were of progressively smaller magnitude. The kernel number and kernel weight per spike also increased with N-rate giving a peak between 270 and 360 kg N ha−1. With increasing S grain yield and tiller number/area increased while kernel number and kernel weight per spike decreased progressively. It was impossible to maximize yield and yield components at a given combination of N, S, and irrigation. According to the model, grain yield and tiller number were maximized at the highest level of N and S, while kernel number and kernel weight/spike were maximized at the lowest S (50 kg ha−1) and about 314 kg N ha−1 under adequate water supply. On the basis of the findings of this study and output of the model, 180–360 kg N ha−1, 150–250 kg S ha−1 and two post-sowing irrigations (at tillering and at boot stage) in addition to a preplant irrigation was recommended for optimum yield. An additional irrigation might be required depending on the weather conditions during the grain filling period.
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    Dynamics of C, N, P and S in grassland soils: a model (1988)
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    Biogeochemistry 5 (1988), S. 109-131 
    Details
    ISSN: 1573-515X
    Keywords: soil organic matter ; nitrogen ; phosphorus ; sulfur ; simulation ; grasslands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract We have developed a model to simulate the dynamics of C, N, P, and S in cultivated and uncultivated grassland soils. The model uses a monthly time step and can simulate the dynamics of soil organic matter over long time periods (100 to 10,000 years). It was used to simulate the impact of cultivation (100 years) on soil organic matter dynamics, nutrient mineralization, and plant production and to simulate soil formation during a 10,000 year run. The model was validated by comparing the simulated impact of cultivation on soil organic matter C, N, P, and S dynamics with observed data from sites in the northern Great Plains. The model correctly predicted that N and P are the primary limiting nutrients for plant production and simulated the response of the system to inorganic N, P, and S fertilizer. Simulation results indicate that controlling the C:P and C:S ratios of soil organic matter fractions as functions of the labile P and S levels respectively, allows the model to correctly simulate the observed changes in C:P and C:S ratios in the soil and to simulate the impact of varying the labile P and S levels on soil P and S net mineralization rates.
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    Mineralization of N and P along a trophic gradient in a freshwater mire (1988)
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    Biogeochemistry 6 (1988), S. 31-43 
    Details
    ISSN: 1573-515X
    Keywords: nitrogen ; phosphorus ; mineralization ; productivity ; peatlands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Release of inorganic nitrogen and phosphorus in the soil of a peatland (fen) in The Netherlands was measured by means of an in situ incubation technique. Three sampling stations were chosen along a gradient in the plant productivity and water chemistry of the fen. The station with the highest biomass production was located near the ditch that supplied the fen with water in amounts matching water losses through evaporation and downward percolation to the groundwater. Water chemistry at this station strongly resembled that of the ditch water. The two stations remote from the ditch had much lower plant biomass, and significantly lower pH, conductivity, and calcium and bicarbonate concentrations. The vegetation at these two stations was characterized by a thick Sphagnum carpet. The release of inorganic N and P was much faster at the two stations remote from the ditch than at that located near the ditch. The differences in mineralization rate are probably due to the differences in water chemistry; phosphates are more soluble at low than at high pH. The fast N mineralization at stations with a thick Sphagnum carpet may be related to the chemical composition of Sphagnum litter. The difference in productivity is not explained by the N and P mineralization rates. Direct supply of N and P from the ditch are probably the main cause of the high productivity at the station bordering the ditch.
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    Derivation of critical nutrient concentrations for growth rate from data from field experiments (1988)
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    Plant and soil 109 (1988), S. 159-169 
    Details
    ISSN: 1573-5036
    Keywords: Brassica oleracea vargemmifera ; Brussels sprout ; model ; nitrate ; nitrogen ; sap ; simulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Present methods for determining critical nutrient concentrations in plants and soils are unsatisfactory if concentrations change with time while the crop is growing. In such cases the critical concentration can only be applied in relation to growth rate at any given moment. For interpreting field experiments this introduces considerable difficulties: two possible approaches to these problems are suggested, one of which uses a simple simulation model. Results from a Brussels sprout nitrogen experiment are used to show how, using this approach, a single critical sap nitrate concentration (380 mg NO3 N.l−1 for 95% of potential growth rate) may serve to explain the results at all growth stages in three seasons.
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    Response of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) to some different fertilizers applied at planting (1988)
    Springer
    New forests 2 (1988), S. 89-110 
    Details
    ISSN: 1573-5095
    Keywords: slow release fertilizers ; nitrogen ; phosphorus ; nutrient uptake ; planting stock ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Four fertilization at planting experiments were conducted with Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) on eastern Vancouver Island. In experiment 1 Agriform (20-10-5, AGR) and Osmocote (17-7-12, OSM) supplied N at 0, 4.2, 8.4, 16.8 or 33.6 g/tree either broadcast, within 15 cm of the tree, or in a hole 15 cm from the tree (adjacent). In experiment 2 AGR, diammonium phosphate (21-55-0, DAP), ammonium sulphate (21-0-0, AMS), sulphur coated urea (35-0-0, SCU) supplied N at 0, 8.4, 16.8 and 25.2 g/tree. Triple superphosphate (0-45-0, TSP) supplied P at the same levels as DAP: 0, 9.6, 19.2 and 28.8 g/tree. In experiment 3 AGR and SCU (32-0-0) supplied N at 0, 8.4 and 16.8 g/tree. In experiment 4 DAP was used to fertilize trees on five different dates, between March and October, and each treatment supplied 16 g N/tree. Two-year old, bare root, planting stock was used except in experiment 3, where container stock was compared with bare root stock. Little growth response was obtained after one year, but height growth responses of 12 to 31% were measured after 3 to 6 years with fertilizers supply 8.4 to 16.8 g N per tree. Growth responses were little affected by the type of fertilizer and were primarily due to N, with release rate having no marked effect. The exception to this was TSP which did not increase growth but did increase survival. Survival was reduced by AMS and to a lesser extent by AGR. Container seedlings responded more to fertilization at planting than bare root seedlings. Seedling N, P and K concentrations and contents declined following planting for 6 months and only started to recover after July. Application of fertilizer caused a small increase in seedling nutrient concentration regardless of date, but this had no detectable effect on dry weight measured six weeks later.
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    Growth regulation of Scots pine seedlings with different fertilizer compositions and regimes (1988)
    Springer
    New forests 2 (1988), S. 119-130 
    Details
    ISSN: 1573-5095
    Keywords: Pinus sylvestris ; fertilization ; nitrogen ; potassium ; phosphorus ; outplanting performance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Scots pine (Pinus sylvestris L.) seedlings were grown in containers filled with peat, using two different fertilizers and three different fertilizer regimes. Seedling shoot and root growth and shoot content of nitrogen, potassium and phosphorus were followed in the nursery and after outplanting in the field. Attempts to regulate growth rate by an exponential nutrient supply were not successful, but the root/shoot ratio was influenced by the fertilization regime. Internal nitrogen concentration was stable only for seedlings with low relative growth rate, while seedlings with high nutrient supply in the nursery showed strong nutrient dilution in the shoot after planting.
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    Vesicular-arbuscular mycorrhizal infection of lucerne roots in a cellulose-amended soil (1988)
    Springer
    Plant and soil 112 (1988), S. 99-104 
    Details
    ISSN: 1573-5036
    Keywords: biological control ; cellulose ; nitrogen ; VAM fungi ; VAM symbiosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Lucerne plants inoculated with vesicular-arbuscular mycorrhizal fungi were grown in pots in a sandy soil amended or not amended with cellulose. Whatever the endophyte or cellulose sources used, the rate of VAM colonization was lower in amended soil. The inhibition of VAM infection increased with the cellulose concentration in the soil. Sequential harvest experiments showed a clear reduction of root colonization from the early stages of plant growth. The effectiveness of cellulose in reducing VAM colonization was influenced by the addition of N fertilizer.
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    C, N, and S mineralization of crop residues as influenced by crop species and nutrient regime (1988)
    Springer
    Plant and soil 106 (1988), S. 35-41 
    Details
    ISSN: 1573-5036
    Keywords: carbon ; crop residue ; mineralization ; nitrogen ; organic matter ; sulfur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The mineralization of C, N, and S from residues of three different crop species (wheat, lentil, and rape) grown under diverse nutritional regimes was measured over a 12-week incubation period under controlled conditions. The rate of decomposition, as measured by CO2 evolution, varied considerably among treatments and appeared to be controlled almost entirely by N content of the residue (R2=0.98). Similarly, N mineralization was strongly tied to N concentration. The critical N concentration, below which significant immobilization of N occurred, declined over time, ranging from 1.9% at day 14 to 1.1% at day 84. Mineralization of S was positively correlated with initial S concentration (R2=0.95) and negatively related to N concentration, apparently because of a dilution effect. The results demonstrate that decomposition and N and S mineralization of crop residues, under conditions prevalent in the experiment, are primarily a function of their nutrient concentrations rather than biochemial composition related to crop species. As a result, it should be possible to enhance rate of residue decomposition, increase quantities of N and S mineralized, and avert detrimental immobilization losses in the following year by governing the nutritional regime under which the crop is grown.
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    URL: http://dx.doi.org/10.1007/BF02371192
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    Lignin and nitrogen in the decomposition of leaf litter in a sub-tropical forest ecosystem at Shiroy hills in north-eastern India (1988)
    Springer
    Plant and soil 106 (1988), S. 59-64 
    Details
    ISSN: 1573-5036
    Keywords: decomposition ; lignin ; litter ; nitrogen ; sub-tropical-forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The effect of the initial lignin and nitrogen contents of the leaves of five tree species, on their decomposition dynamics, was studied in the sub-tropical forest ecosystem existing at Shiroy hills. The decomposition dynamics of litter materials are described by inverse linear relationships between the percentage of the original biomass remaining and the nitrogen concentration in the residual material. Initial lignin and nitrogen were highly correlated with remaining biomass (r=0.94 and 0.77). The rate constants (K), for the annual leaf mass loss, ranged from −0.18 to −0.56. The values for initial lignin (%), initial nitrogen (%), the ratio between initial lignin, initial nitrogen and the annual decomposition rate constants were compared with similar results from other studies in various climatic zones of the world.
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    URL: http://dx.doi.org/10.1007/BF02371195
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    Isolation and characterization of a new antifungal metabolite ofTrichoderma reesei (1988)
    Springer
    Plant and soil 107 (1988), S. 81-84 
    Details
    ISSN: 1573-5036
    Keywords: antifungal metabolite ; biological control ; Trichoderma reesei
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A mycelial extract ofTrichoderma reesei (P-12) was separated into four fractions by high performance liquid chromatography (HPLC). Out of these, two were found to exhibit antifungal activity when tested against plant pathogenic fungi. The level of antifungal compounds was higher in media containing glucose as the carbon source as compared to one containing cellulose. The synthesis of these antifungal compounds started after 3 days of inoculation at 30°C and continued upto 8 days. No further increase was recorded beyond this period.
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    The response ofPlantago lanceolata L. andP. major L. spp.major to nitrate depletion (1988)
    Springer
    Plant and soil 107 (1988), S. 197-206 
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    ISSN: 1573-5036
    Keywords: nitrate ; nitrate reductase activity ; nitrogen ; nitrogen use efficiency ; osmotic solutes ; Plantago lanceolata ; Plantago major ; redistribution ; sugars
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract To study aspects of the ecology of grassland species, in a comparative experiment, plants ofP. lanceolata andP. major were grown in pots in a greenhouse, and subjected to a gradual nitrate depletion for several weeks. Control plants were weekly supplied with nitrate. Growth, leaf appearance and disappearance, concentrations of cations and inorganic anions, soluble and insoluble reduced nitrogen concentrations,in vivo nitrate reductase activity (NRA) and the concentration of non-structural carbohydrates in several parts of the plants were followed. Depletion of nitrate caused a reduction of shoot growth, both in biomass and number of leaves. Withering of leaves increased. Accumulation of root dry matter was little (P. lanceolata), or not (P. major) affected. The concentration of reduced nitrogen in all tissues also decreased, both that of the soluble and that of the insoluble fraction. As a result, nitrogen use efficiency (NUE, g dry matter produced per mmol N incorporated) increased by nitrate depletion. NRA was higher in the roots than in the leaves, and decreased with increasing nitrate depletion. In control plants, nitrate became also limiting. This resulted in decreasing nitrate concentrations in leaves and roots. In the leaves, the decrease in nitrate concentration was preceded by a decrease in NRA. The decrease of the nitrate concentration was parallelled by an increase in the concentration of soluble sugar. No major differences in the response towards nitrate depletion were observed between the two species.
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    URL: http://dx.doi.org/10.1007/BF02370547
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    Plant and soil nitrogen dynamics in California annual grassland (1988)
    Springer
    Plant and soil 110 (1988), S. 9-17 
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    ISSN: 1573-5036
    Keywords: grassland ; Mediterranean ; microbial biomass ; nitrogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seasonal changes in soil water and nitrogen availability were related to the phenology and growth of plants in California annual grassland. Plant accumulation of nitrogen was mainly confined to two short periods of the year: fall and early spring. At these times, plants were in the vegetative growth phase, roots were growing rapidly and soil moisture was high. During these periods, soil nitrate was low or depleted. High flux of nitrogen in this ecosystem, however, is indicated by the rapid disappearance of the previous year's detrital material, high microbial biomass, and high mineralizable nitrogen and nitrification potential. At the end of the summer drought, significant amounts of the previous year's detrital material had disappeared, chloroform-labile N (expressed as microbial biomass N) was at its seasonal maximum, and soil inorganic nitrogen pools were high. This suggests inorganic nitrogen flux during the drought period. The ‘drought escaper’ life history characteristics of annual grasses in California annual grassland, however, may prevent plants from utilizing available nitrogen during a large part of the year.
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    Nutrient release from decomposing foliar litter of three tree species with spicial reference to calcium, magnesium and potassium dynamics (1988)
    Springer
    Plant and soil 110 (1988), S. 49-55 
    Details
    ISSN: 1573-5036
    Keywords: Acer rubrum ; calcium ; cations ; Cornus florida ; decomposition ; litter ; magnesium ; nitrogen ; nutrient release ; phosphorous ; potassium ; Quercus prinus ; sulfur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Calcium, magnesium and potassium dynamics in decomposing litter of three tree species were measured over a two-year period. The speices studied were flowering dogwood (Cornus florida), red maple (Acer rubrum) and chestnut oak (Quercus prinus). The order of decomposition was:C. florida〉A. rubrum〉Q. prinus. Calcium concentrations increased following any initial leaching losses. However, there were net releases of Ca from all three litter types since mass loss exceeded the increases in concentration. Net release of Ca by the end of two years from all three species combined was 42% of initial inputs in litterfall. Magnesium concentrations increased in the second year, following decreases due to leaching during the first year inC. florida andA. rubrum litter. Net release of Mg by the end of two years was 58% of initial inputs. Potassium concentrations decreased rapidly and continued to decline throughout the study. Net release of K by the end of two years was 91% of initial inputs. These data on cation dynamics, and similar data on N, S and P dynamics from a previous study, were combined with annual litterfall data to estimate the release of selected nutrients from foliar litter of these tree species at the end of one and two years of decomposition. The relative mobility of all six elements examined in relation to mass loss after two years was; K〉Mg〉mass〉Ca〉S〉P〉N.
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    Estimation of residual N effect of faba bean and pea on two succeeding cereals using15N methodology (1988)
    Springer
    Plant and soil 110 (1988), S. 81-89 
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    ISSN: 1573-5036
    Keywords: isotope dilution method ; 15N ; N2 fixation ; nitrogen ; Pisum sativum ; residue ; rhizobium ; Vicia faba L.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A field experiment was conducted using15N methodology to study the effect of cultivation of faba bean (Vicia faba L.), pea (Pisum sativum L.) and barley (Hordeum vulgare L.) on the N status of soil and their residual N effect on two succeeding cereals (sorghum (Sorghum vulgare) followed by barley). Faba bean, pea and barley took up 29.6, 34.5 and 53.0 kg N ha−1 from the soil, but returned to soil through roots only 11.3, 10.8 and 5.7 kg N ha−1, respectively. Hence, removal of faba bean, pea and barley straw resulted in a N-balance of about −18, −24, and −47 kg ha−1 respectively. A soil nitrogen conserving effect was observed following the cultivation of faba bean and pea compared to barley which was of the order of 23 and 18 kg N ha−1, respectively. Cultivation of legumes resulted in a significantly higher AN value of the soil compared to barley. However, the AN of the soil following fallow was significantly higher than following legumes, implying that the cultivation of the legumes had depleted the soil less than barley but had not added to the soil N compared to the fallow. The beneficial effect of legume cropping also was reflected in the N yield and dry matter production of the succeeding crops. Cultivation of legumes led to a greater exploitation of soil N by the succeeding crops. Hence, appreciable yield increases observed in the succeeding crops following legumes compared to cereal were due to a N-conserving effect, carry-over of N from the legume residue and to greater uptake of soil N by the succeeding crops when previously cropped to legumes.
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    URL: http://dx.doi.org/10.1007/BF02143543
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    Influence of hydrological fluctuations on the growth and nutrient dynamics ofPhalaris arundinacea L. in a riparian environment (1988)
    Springer
    Plant and soil 112 (1988), S. 53-60 
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    ISSN: 1573-5036
    Keywords: carbon ; flood plain ; macrophytes ; nitrogen ; nutrient cycling ; Phalaris arundinacea ; phosphorus ; potassium ; wate table
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Seasonal changes in aboveground and belowground tissues ofPhalaris arundinacea L. were studied in a population colonizing an ancient meander of the Garonne river (France) submitted to important fluctuations of the permanent water table. Waterlogged conditions in spring stopped the growth of rhizomes and promoted the translocation of nutrient to the shoots. The early senescence of plants after flowering could be related to the withdrawal of the water table. It was characterized by a distribution of nutrients in belowground tissues and a release in litter and soil. Aerated conditions in late summer permitted the growth of belowground tissues. At this time a partition of resources between aboveground and belowground biomass of a new generation of plants was observed. Rising water and decreasing temperatures in winter induced the death of aboveground parts. Reconstitution of nutrient stocks in rhizomes and losses by leaching then occured. Beside a very high primary production this strategy confers toPhalaris arundinacea a great interest in different uses, especially in the removal of nutrients from water in riparian zones as in artificial sites.
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    Biological control ofFusarium oxysporum f.sp.cubense in banana by inoculation withPseudomonas fluorescens (1988)
    Springer
    Plant and soil 107 (1988), S. 3-9 
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    ISSN: 1573-5036
    Keywords: bacterization ; biological control ; Panama wilt of banana ; Pseudomonas fluorescens
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Native strains ofPseudomonas fluorescens exhibitedin vitro antibiosis towards isolates of races 1 and 4 ofFusarium oxysporum f.sp.cubense, the Panama wilt pathogen of banana. The seedlings ofMusa balbisiana seedlings treated withP. fluorescens showed less severe wilting and internal discolouration due toF. oxysporum f.sp.cubense infection in greenhouse experiments. In addition to suppressing Panama wilt, bacterized seedlings ofM. balbisiana also showed better root growth and enhanced plant height.
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    Effects of root pruning of wheat at different nitrogen levels (1988)
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    Plant and soil 109 (1988), S. 128-130 
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    ISSN: 1573-5036
    Keywords: nitrogen ; root pruning ; shoot ; root ratio ; Thornley's model ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In two experiments, wheat plants growing in solutions of different nitrogen concentration were subjected to root pruning. In higher concentrations of nitrogen the growth rate was higher, and the proportional allocation of growth to shoot higher, but pruning did not affect the allocation of growth at either level of nitrogen. This result gives no support to Thornley's source-sink model of the control of shoot: root ratio.
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    Rice straw decomposition in rice-field soil (1988)
    Springer
    Plant and soil 109 (1988), S. 145-146 
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    ISSN: 1573-5036
    Keywords: biomass ; carbon ; decomposition ; nitrogen ; phosphorus ; rice straw
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Rice straw, buried in a rice-field during the dry season decomposed at a rate of 0.0075 day-1. Seventy five percent of the biomass, 70 percent carbon, 50 percent nitrogen and 30 percent phosphorus remained after 139 days of decomposition. Rice straw decomposition furnished 33% N and 8% P of the total nitrogen and phosphorus provided by man.
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    URL: http://dx.doi.org/10.1007/BF02197596
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    The effectiveness of some Indonesian strains of Rhizobium on four tropical legumes (1988)
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    Plant and soil 108 (1988), S. 171-177 
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    ISSN: 1573-5036
    Keywords: Legume growth ; nitrogen ; nodulation ; Rhizobium strains
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Nodules were collected from 14 legume species from the Indonesian Islands of South Sulawesi, Java and Sumatra. Their rhizobia were isolated and growth characteristics, nodulation ability and nitrogen fixing effectiveness were assessed against recommended commercially available Australian strains. The test legumes wereMacroptilium atropurpureum Urb. cv. Siratro,Vigna unguiculata (L.) Walp. cv Eureka,Centrosema pubescens Benth cv. Belalto andDesmodium heterocarpon (L) DC. A significant portion of the native rhizobial isolates were of the fast growing type. Dry matter and total nitrogen production forM. atropurpureum andV. unguiculata was highest when inoculated with native strains while the commerical strains produced superior dry matter production forC. pubescens andD. heterocarpon. However the total nitrogen production of native and commercial strains was not significantly different for the latter two legumes. The study indicated that a potential exists for developing inocula from local Rhizobium strains.
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    URL: http://dx.doi.org/10.1007/BF02370112
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    Nitrogen mineralization ofSesbania sesban used as green manure for lowland rice in Sri Lanka (1988)
    Springer
    Plant and soil 108 (1988), S. 201-209 
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    ISSN: 1573-5036
    Keywords: decomposition ; green manure ; litterbag ; nitrogen ; paddy rice ; Sesbania sesban ; Sri Lanka
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Sesbania sesban was evaluated as green manure crop for lowland rice in the Dry Zone of Sri Lanka. The legume was grown during a fallow period before lowland rice (Oryza sativa) and ploughed under just before transplanting. Weight loss and nitrogen content in litterbags containing leaves, stems and roots of the legume were monitored. Comparisons were made between rice yields from 20 m2 plots after green manuring in combination with different nitrogen fertilizer levels (0, 2.4, 4.8 and 7.2 gm−2) and nitrogen fertilizer (9.6 gm−2) alone. Above-ground biomass ofS. sesban was 440 gm−2 (dry wt) when ploughed under after 84 days growth. N-content in leaves, stems and roots was 3.76%, 0.41% and 0.73%, respectively. This gave a N-input fromS. sesban of 9.2 gm−2 (8.3 g from above-ground parts and 0.9 g from roots). The corresponding K and P inputs were 7.3 and 0.6 gm−2 respectively. The nitrogen rich leaves, which contained 88% of the nitrogen in the above-ground parts, decomposed and released its nitrogen much more rapidly than the stems and roots. After only four days the leaves had released 5.3 g Nm−2 and after 14 days they had released 6.4 g Nm−2. The highest rice yield (505 gm−2) was obtained usingS. sesban and 4.8 gm−2 of N-fertilizer. The yields with only N-fertilizer or onlyS. sesban were 442 gm−2 and 396 gm−2, respectively. Due to the rapid decomposition of the nitrogen rich leaves,S. sesban did not behave as a slow release fertilizer. Thus, it is not necessary to apply nitrogen fertilizers as a basal dose.
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    URL: http://dx.doi.org/10.1007/BF02375650
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    Co-inoculation with antibiotic-producing bacteria to increase colonization and nodulation by rhizobia (1988)
    Springer
    Plant and soil 108 (1988), S. 211-219 
    Details
    ISSN: 1573-5036
    Keywords: antibiotics ; biological control ; Bradyrhizobium ; Rhizobium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A study was conducted to determine whether colonization of legume roots and nodulation byRhizobium meliloti andBradyrhizobium japonicum could be enhanced by using inocula containing microorganisms that produce antibiotics suppressing soil or rhizosphere inhabitants but not the root-nodule bacteria. An antibiotic-producing strain of Pseudomonas and one of Bacillus were isolated, and mutants ofR. meliloti andB. japonicum sp. resistant to the antibiotics were used. The colonization of the alfalfa rhizosphere and nodulation byR. meliloti were enhanced by inoculation of soil withPseudomonas sp. in soil initially containing 2.7×105 R. meliloti per g. The colonization of soybean roots byB. japonicum was enhanced by inoculating soil with three cell densities ofBacillus sp., and nodulation was stimulated byBacillus sp. added at two cell densities. In some tests, the dry weights of soybeans and seed yield increased as a result of these treatments, and co-inoculation with Bacillus also increased pod formation. Inoculation of seeds withBacillus sp. and the root-nodule bacterium enhanced nodulation of soybeans and alfalfa, but colonization byB. japonicum andR. meliloti was stimulated only during the early period of plant growth. Studies were also conducted withStreptomyces griseus and isolates ofR. meliloti andB. japonicum resistant to products of the actinomycete. Nodulation of alfalfa byR. meliloti was little or not affected by the actinomycete alone; however, both nodulation and colonization were enhanced if the soil was initially amended with chitin andS. griseus was also added. Chitin itself did not affectR. meliloti. Treatments of seeds with chitin orS. griseus alone did not enhance colonization of alfalfa roots byR. meliloti or soybean roots byB. japonicum, but the early colonization of the roots by both bacterial species was promoted if the seeds received both chitin andS. griseus; this treatment also increased nodulation and dry weights of alfalfa and soybeans and the N content of alfalfa. It is suggested that co-inoculation of legumes with antibiotic-producing microorganisms and root-nodule bacteria resistant to those antibiotics is a promising means of promoting nodulation and possibly nitrogen fixation.
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    The use of ion-exchange resin bags for measuring nutrient availability in an arid ecosystem (1988)
    Springer
    Plant and soil 105 (1988), S. 105-111 
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    ISSN: 1573-5036
    Keywords: chronosequence ; desert ; ion-exchange resins ; mineralization ; nitrogen ; nutrient availability ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Anin situ resin bag technique was used to measure the relative availabilities of N and P along a chronosequence of soils in southern New Mexico, and was compared to two more common indices of nutrient availability. Accumulations of N and P during 10-week intervals over an 18 month period were separable into wet season (September–January) and dry season (February–August) groups, with wet season values significantly greater than dry season values. Only accumulations during the wet season showed significant differences among sites, thus stressing the role of field water regime in interpreting resin accumulation results. Total mineral N (NO3+NH4) sorbed by resins was significantly correlated to laboratory N mineralization rates. Although accumulation patterns of N and P were similar to patterns of %N and %P in shrub species growing along the chronosequence, these similarities were not statistically significant. A laboratory experiment demonstrated that bicarbonate-form anion resins are preferable to hydroxyl-form resins, as long as standards are made from solutions extracted by resins to account for variable ion recovery efficiencies.
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    Transformations of carbon and nitrogen in a Calciorthid soil amended with a range of organic residues (1988)
    Springer
    Plant and soil 105 (1988), S. 205-212 
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    ISSN: 1573-5036
    Keywords: extractable carbon ; fulvic acids ; humic acids ; humification ; mineralization ; nitrogen ; oxidizable carbon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A calcareous soil was treated with an organic fertilizer mixture of grape debris and peat, or with pig manure, chicken manure, city refuse or with aerobic or anaerobic sewage sludges. Changes in different fractions of carbon and nitrogen were followed by analysis of the soil, immediately after these additions, after they had decomposed for six months in the soil, after a maize harvest, and after a subsequent barley harvest. The various forms of carbon had decreased after six months. The rate of decrease varied with the nature of the organic materials. In all samples, the fulvic acids fraction decreased most. The main transformations happened during the first six months whether there was a crop growing or not, but the crops had no influence on the breakdown of the organic materials. The ratio of humic acids/fulvic acids had increased after six months of humification and, in general terms, the final values of the ratio oxidizable carbon/extractable carbon were lower than the initial ones, indicating a higher degree of humification in the organic matter by the end of the experiment. The total nitrogen level remained practically constant after the first six months of humification even after the second crop. Part of the organic nitrogen of the soil samples amended with chicken manure, city refuse or the two sludges was transformed into mineral nitrogen during the humification process. The extractable nitrogen values increased because of the fertilizer applied during the pot trials.
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    Nitrogen requirements in young Douglas-fir of the Pacific North-west (1988)
    Springer
    Nutrient cycling in agroecosystems 15 (1988), S. 173-179 
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    ISSN: 1573-0867
    Keywords: Douglas-fir ; urea ; basal area increment ; growth response ; nitrogen ; critical level
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A series of fourteen Pacific North-west Douglas-fir installations, ranging in age from 6 to 26 years were analysed with respect to site factors, foliage nutrients, and growth response to applied fertilizer. Unfertilized basal area increment ranged from 1.2 to 3.1 m2 ha−1 yr−1 with no apparent relationship with soil, stand age or site index. Basal area increment was correlated with foliage N and a critical level for N was calculated as 1.7%. Applications of 220 kg N ha−1 as urea increased growth between 0 and 95% of the unfertilized basal area growth, with an average of 24.9%. Response could be predicted from foliage N and unfertilized basal area increment. When the same relationships were applied to previously older stand data, results were more variable as elements such as B and S showed evidence of being limiting.
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    Survival ofSclerotinia minor Jagger sclerotia in solarized soil (1988)
    Springer
    Plant and soil 109 (1988), S. 49-55 
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    ISSN: 1573-5036
    Keywords: biological control ; lettuce drop ; Sclerotinia minor ; soil-borne plant pathogens ; soil solarization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soil solarization reduced both recovery and viability ofSclerotinia minor sclerotia depending on the depth of burial. Highest reduction of these parameters was obtained at 4–6 cm depth (55%) and 0–2 cm depth (96%) respectively. Soil solarization accelerated the exponential decay of sclerotia observed in natural soil. In the upper 6 cm of soil this decay was so fast that after about 14 days loss of the sclerotial viability approached values recorded at the end of the treatment after 41 days. The number of sclerotia colonized by microorganisms is higher in solarized than in non-solarized plots.
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    Effect of nitrogen, phosphorus and potassium on spikelet sterility induced by low temperature at the reproductive stage of rice (1988)
    Springer
    Plant and soil 109 (1988), S. 31-36 
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    ISSN: 1573-5036
    Keywords: nitrogen ; phosphorus ; potassium ; rice ; low temperature ; reproductive stage ; flag leaf ; auricle distance ; spikelet sterility
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Spikelet sterility induced by low temperature at the reproductive stage of rice increased further with the increase of nitrogen supply. Spikelet sterility in Fujisaka-5 did not increase due to low temperature when nitrogen supply was increased from 10 to 40 ppm and at 80 ppm nitrogen supply it was less affected than IR36. Total nitrogen content in the leaves increased with the increase of nitrogen supply and was forced to be associated with the spikelet sterility induced by low temperature. Based on auricle distance between the last two leaves, the most sensitive stage to low temperature damage differed in Fujisaka-5 and IR36. Spikelet sterility induced by low temperature for 10 days was very high in both the varieties and the effect of nitrogen was not clear. The effect of phosphorus on the spikelet sterility induced by low temperature at reproductive stage was not clear except that at the highest phosphorus (P) level (10 ppm) the spikelet sterility increased both in Fujisaka-5 and IR36. Spikelet sterility induced by low temperature at the reproductive stage of rice decreased with the increase of Potassium (K) supply in both Fujisaka-5 and IR36. With an increase of potassium supply, nitrogen (N) content decreased in the leaves and panicles and spikelet sterility induced by low temperature decreased with an increase of the K to N ratio in the leaves and panicles. The results suggest that potassium might play a major role to counteract the low temperature damage at the reproductive stage of rice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02197577
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    Comparisons of primary production and nutrients absorption by aMiscanthus sinensis community in different soils (1988)
    Springer
    Plant and soil 112 (1988), S. 143-149 
    Details
    ISSN: 1573-5036
    Keywords: absorption ; clay ; Miscanthus sinensis ; nitrogen ; phosphorus ; primary production ; serpentine gangue ; standing biomass
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Soil properties, primary production, nitrogen and phosphorus uptake in aMiscanthus sinensis community on serpentine gangue area were compared with that on nonserpentine area. Soil water content, soil pH and nitrogen content were quite different between the serpentine gangue area and nonserpentine area; but phosphorus content of the soil was similar between the two sites. The maximum above-ground net production in the serpentine gangue and nonserpentine areas was 4.5±0.2 kg m−2 yr−1 and 7.8±0.2 kg m−2 yr−1, respectively. The total maximum standing biomass in the serpentine gangue and nonserpentine areas was 8.5±0.8 kg m−2 and 11.9±0.4 kg m−2, respectively. Nitrogen uptake by plants in the nonserpentine area was 2.4 times greater than that in the serpentine gangue area. Phosphorus uptake by plants were similar for the two sites. The most probable reasons for the small biomass produced by theMiscanthus sinensis community in this serpentine gangue area are the low levels of nitrogen and water availability in the soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02181764
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    Nitrogen fixation, transfer and turnover in upland and lowland grass-clover swards, using15N isotope dilution (1988)
    Springer
    Plant and soil 112 (1988), S. 247-254 
    Details
    ISSN: 1573-5036
    Keywords: isotope dilution ; 15N ; nitrogen ; nitrogen fixation ; nitrogen transfer ; ryegrass ; white clover
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The stable isotope15N is particularly valuable in the field for measuring N fixation by isotope dilution. At the same time other soil-plant processes can be studied, including15N recovery, and nitrogen transfer between clover and grass. Three contrasting sites and soils were used in the present work: a lowland soil, an upland soil, and an upland peat. Nitrogen fixation varied from 12 gm−2 on lowland soil to 2.7 gm−2 on upland peat. Most N transfer occurred on upland soil (4.2 gm−2) which, added to nitrogen fixed, made a total of 8.7 gm2 input during summer 1985.15N recovery for the whole experiment was small, around 25%. Measurement of dead and dying leaves, stubble and roots, suggests that plant organ death is the first stage in N transfer from white clover to ryegrass, through the decomposer cycle. Decomposition was fastest on lowland soils, slowest on peat. On lowland soil this decomposer nitrogen is apparently subverted before transfer, probably by soil microbes. Variations in natural abundance of15N in plants were found in the two species on the different soils. These might be used to measure nitrogen fixation without adding isotope, but the need for many replicates and repeat samples would limit throughput.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02140002
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    A test method for pesticide tolerance in minute parasiticHymenoptera (1987)
    Springer
    BioControl 32 (1987), S. 83-95 
    Details
    ISSN: 1573-8248
    Keywords: Aphytis ; biological control ; parasitic Hymenoptera ; pesticide tolerance ; resistance ; toxicological methodology ; Aphytis ; lutte biologique ; hyménoptères parasites ; pesticide ; tolérance ; résistance ; essais toxicologiques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé La résistance aux pesticides est devenue largement répandue chez les ravageurs, mais elle n'a été que rarement mentionnée chez leurs ennemis naturels. Des agents de lutte biologique résistants peuvent jouer un rôle important dans les programmes de Lutte Intégrée en réduisant le nombre d'espéces nécessitant une lutte chimique et en limitant l'ensemble des applications de pesticides. Le manque de techniques toxicologiques appropriées aux insectes petits, fragiles et hautement actifs, peut limiter les projets de choix et de sélection. Les méthodes toxicologiques disponibles ont été trouvées comme non satisfaisantes pour notre travail avecAphytis holoxanthus DeBach—(Hymenoptera : Aphelinidae), parasite du Pou de Floride,Chrysomphalus aonidum (L.) (Homoptera : Diaspididae). Une méthode alimentaire test, basée sur l'accès contrôlé à des solutions pesticides appâts, a été développée. Des concentrations progressives de malathion dans des solutions de sucrose ont été offertes dans des cellules de Munger adaptées en combinant ainsi les effets par contact et par ingestion du poison. Les cages d'élevage et de traitment, les procédés de fabrication et de manipulation ont été adaptés pour le travail avec les grands nombres d'individus requis pour des résultats statistiquement significatifs. La méthode se prête à la récupération des survivants qui pourraient être utilisés dans des expériences de multiplication et de sélection. Les résultats obtenus avec plusieurs populations test sont représentés par le rapport entre le dosage et la mortalité dont les valeurs de la DL 50 correspondante et leur limite ont été calculées. Le procédé décrit peut se révéler souhaitable pour des programmes de sélection avec des espèces semblables, dont beaucoup sont d'importants agents de lutte biologique et avec un large éventail de pesticides combinant les effets de contact et d'ingestion.
    Notes: Abstract In contrast to many pest species, important biological control agents have only rarely been found to be pesticide resistant. Biochemical and ecological mechanisms have been implicated, but lack of toxicological techniques suitable for the minute and fragile insects concerned may limit screening and research projects. Standard techniques are criticized, and a method utilizing controlled access to pesticidecontaining sucrose solutions is described. The method was used to test tolerance ofAphytis holoxanthus to malathion, and is suggested for screening and selection experiments with this and similar species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02390934
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    Introduction dans le Sud-Est de la france d'un parasite:Pauesia cedrobii [Hym.: Aphidiidae] du puceron:Cedrobium laportei [Hom.: Lachnidae] du cèdre de l'atlas:Cedrus atlantica (1987)
    Springer
    BioControl 32 (1987), S. 127-141 
    Details
    ISSN: 1573-8248
    Keywords: Cedrus atlantica ; Cedrobium laportei ; lutte biologique ; introduction auxiliaire ; Pauesia cedrobii ; Cedrus atlantica ; Cedrobium laportei ; biological control ; natural enemies introduction ; Pauesia cedrobii
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Summary Pauesia cedrobii Stary et Leclant, a specific parasite of the cedar aphidCedrobium laportei Rem. has been collected in the middle Atlas (Morocco) for introduction into a stand of cedar (Cedrus atlantica Manetti) in the south-east of France in spring 1981. The parasite was collected as mummified aphids in Morocco and kept in climatised room for emergence in order to get rid of hyperparasites. After copulation, 225 adults were released in sleeve cages put on branches with colonies ofC. laportei. The development of host and of parasite population was followed both at the point of release and in the general area. The definitive establishment of the parasite in the area occurred 1 year after release aided by a particularly mild autumn and winter, which promoted the multiplication of the host. The parasite is definitely established and is still present 4 years after the release. During this time it was dispersed to other cedar forests in the south-east of France. Eight species of local hyperparasites have attackedP. cedrobii, but have not prevented the success of the introduction.
    Notes: Résumé Le parasitePauesia cedrobii Starý et Leclant, spécifique du puceron du CèdreCedrobium laportei Remaudière, a été récolté dans le Moyen-Atlas, (Maroc) puis introduit dans un peuplement de cèdre (Cedrus atlantica Manetti) du sud-est de la France au printemps 1981. La méthode utilisée a consisté en une introduction directe des parasites, préalablement isolés sur le lieu de récolte (momies) puis mis à éclore en chambre climatisée de façon à éliminer les hyperparasites. Après accouplement, 225 adultes ont été introduits dans des manchons installés sur des rameaux abritant des colonies deC. laportei. L'évolution des populations de l'hôte et du parasite a été suivie au niveau des points de lâcher d'une part, et dans la parcelle d'autre part. L'installation définitive du parasite dans la parcelle s'est produite, 1 an après le lâcher, grâce à un automne et à un hiver particulièrement doux, qui ont favorisé la multiplication de l'hôte. Le parasite est définitivement implanté: il est encore présent 4 années après le lâcher. Entre temps, il a été étendu à d'autres forêts de cèdre du sud-est de la France. Huit espèces d'hyperparasites autochtones se sont portés surP. cedrobii, mais ceci ne remet pas en cause la réussite de l'introduction de l'aphidiide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02373123
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    RearingTetrastichus gallerucae [hymenoptera: Eulophidae] for biological control of the ELM leaf beetleXanthogaleruca luteola (1987)
    Springer
    BioControl 32 (1987), S. 457-461 
    Details
    ISSN: 1573-8248
    Keywords: Tetrastichus gallerucae ; Xanthogaleruca luteola ; biological control ; rearing techniques ; egg parasitoids ; Tetrastichus gallerucae ; Xanthogaleruca luteola ; lutte biologique ; techniques d'élevages ; parasitoïdes oophages
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Tetrastichus gallerucae (Fonscolombe) a été récolté, en France en 1985 et a été élevé à la Division de Lutte Biologique à Albany, Californie, pour la lutte contreXanthogaleruca luteola (Müller), la galéruque de l'orme, en Californie du nord. On peut élever ce parasitoïde facilement en gardant les œufs sur un substrat humide, pour empêcher leur dessication et en arrêtant la croissance des moisissures par une forte ventilation. Une colonie de laboratoire d'adultes de la galéruque de l'orme fournit constamment des œufs frais pour les parasitoïdes. En 1985 et 1986 plus de 80.000T. gallerucae ont été introduits dans 17 points de lâchers.
    Notes: Abstract Tetrastichus gallerucae (Fonscolombe) was collected in southern France in 1985 and is being reared at the Division of Biological Control in Albany, Ca for use against the elm leaf beetle (ELB),Xanthogaleruca luteola (Müller) in northern California. This egg parasitoid can be reared easily by keeping the beetle eggs on a moist substrate to prevent desiccation and by inhibiting the growth of mold with air currents. A laboratory colony of ELB adults provides a constant supply of fresh eggs for the parasitoids. In 1985 and 1986 over 80,000T. gallerucae were released at 17 sites.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02373514
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    Field evaluation ofAllorhogas pyralophagus [Hym.: Braconidae], imported into texas for biological control of the stalkborerEoreuma loftini [Lep.: Pyralidae] in sugar cane (1987)
    Springer
    BioControl 32 (1987), S. 483-491 
    Details
    ISSN: 1573-8248
    Keywords: Allorhogas pyralophagus ; Eoreuma loftini ; biological control ; sugar cane ; parasite-host interaction ; stalkborers ; Allorhogas pyralophagus ; Eoreuma loftini ; lutte biologique ; canne à sucre ; interaction parasite/hôte ; mineuse de la tige
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé L'ectoparasite grégaireAllorhogas pyralophagus Marsh a été libéré à l'intérieur de cages disposées dans des cultures de canne à sucre elles-même infestées parEoreuma loftini Dyar. Les facteurs qui affectent le taux de parasitisme sont examinés et le rôle du parasite dans la mortalité larvaire de l'hôte est déterminé. Trois essais ont eu lieu respectivement en juillet, septembre et décembre 1984. Le parasitisme moyen a été de 25.2% dans cette étude et fut la source la plus importante de mortalité. Les pyrales sont susceptibles d'être attaquées aussi bien dans la gaine des feuilles, que dans le bourgeon terminal ou dans la tige. Les larves qui pénètrent plus profondément à l'intérieur des tiges sont les moins parasitées. Le succès du parasite est fonction de certains comportements de l'hôte à l'intérieur des tiges.A. pyralophagus est probablement incapable d'effectuer le “contrôle” total d'E. loftini dans la canne à sucre, mais il peut être un élément utile dans un programme bien organisé de lutte contre ce fléau, conjointement avec d'autres espèces de parasites.A. pyralophagus est susceptible de parasiterE. loftini lorsqu'il est présent dans les graminées sauvages servant de plantes hôtes secondaires.
    Notes: Abstract The external, gregarious, braconid parasite,Allorhogas pyralophagus Marsh was mass released into field cages enclosing sugar cane infested with the pyralid,Eoreuma loftini (Dyar) to examine factors affecting parasitism rates and to assess the parasite's potential contribution to borer larval mortality. Three field experiments were conducted in July, September, and December, 1984. Total parasitism was 25.2% for the study and was the single most important source of borer mortality. Borers were equally susceptible to attack in leaf sheaths, whorls, and stalks in general, but larvae tunneling deep within stalks were parasitized less. An interaction between tunneling behavior of the borer and attack strategy of the parasite was important for parasite success.A. pyralophagus is probably unable to effect complete control ofE. loftini in sugar cane becauseA. pyralophagus is physically unable to parasitize borers deep in the stalks. However, the parasite may be useful as part of an intergrated pest management program, acting in concert with other parasite species, or attacking the borer in small-stemed grasses that serve as alternate host plants.
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    URL: http://dx.doi.org/10.1007/BF02373517
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    Parasitism ofLeptinotarsa decemlineata [Coleoptera: Chrysomelidae] byEdovum puttleri [Hymenoptera: Eulophidae] in different cultivars of eggplant (1987)
    Springer
    BioControl 32 (1987), S. 503-510 
    Details
    ISSN: 1573-8248
    Keywords: Colorado potato beetle ; Leptinotarsa decemlineata ; Edovum puttleri ; eggplant ; biological control ; Doryphore ; Leptinotarsa decemlineata ; Edovum puttleri ; aubergine ; lutte biologique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé En vue de quantifier le parasitisme Du Doryphore,Leptinotarsa decemtineata (Say) par le parasitoïde oophageEdovum puttleri Grissell, des expériences furent conduites sur trois différents cultivars d'aubergine,Solanum melongena L. Les niveaux de parasitisme étaient plus élevés (P〈0.05) sur «Black Pride» que sur les autres cultivars. Le pourcentage des pontes parasitées était 1,2 fois plus élevétés par ponte était 1,3 et 1,4 fois plus grant (P〈0.05) sur «Black Price» que sur «Harris Spccial» et «White» respectivement. Le pourcentage d'œufs parasités par ponte et le pourcentage de parasitoïdes adultes émergeant ne variaient pas (P〉0.05) entre les cultivars et s'établissait en moyenne entre 47 et 55 et 73 et 79% respectivement sur tous les cultivars. Les sex-ratio des parasitoïdes éclos ne différaient pas (P〉0.05) entre les cultivars; entre 2,1 et 2,6 fois plus de femelles que de mâles émergeaient des œufs sur tous les cultivars durant la saison-Edovum puttleri supprimait la deuxième génération deL. decemlineata sur «Black Pride» et «Harris Special», mais ne la supprimait pas sur «White».
    Notes: Abstract Experiments were conducted to quantify parasitism of Colorado potato beetle,Leptinotarsa decemlineata (Say), by the egg parasitoid,Edovum puttleri Grissell, on 3 different cultivars of eggplant,Solanum melongena L. Levels of parasitism were higher (P〈0.05) on ‘Black Pride’ than on other cultivars. The percentage of egg masses that were parasitized was 1.2-fold higher (P〈0.05) on ‘Black Pride’ than on ‘Harris Special’ and ‘White’. The number of eggs per mass that were parasitized was 1.3- and 1.4- fold greater (P〈0.05) on ‘Black Pride’ than on ‘Harris Special’ and ‘White’, respectively. The percentage of eggs that were parasitized per mass and percentage of emerged adult parasitoids did not differ (P〉0.05) among cultivars; between 2.1- to 2.6- fold more females than males emerged from eggs on all cultivars during the growing season.Edovum puttleri suppressed the 2nd generation ofL. decemlineata on ‘Black Pride’ and ‘Harris Special’, but did not suppress populations on ‘White’.
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    Biological studies withChrysocharis parksi [Hym.: Eulophidae] a parasite ofLiriomyza spp. [Dipt.: Agromyzidae] (1987)
    Springer
    BioControl 32 (1987), S. 115-126 
    Details
    ISSN: 1573-8248
    Keywords: Liriomyza ; leafminers ; Chrysocharis ; biological control ; parasites ; biology ; Liriomyza ; mineuses de feuille ; Chrysocharis ; lutte biologique ; parasites ; biologie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Des études biologiques ont été réalisées surChrysocharis parksi, parasite endophage des Mouches Agromyzides, mineuses des feuilles.C. parksi parasite avec succès les espèces suivantes du genreLiriomyza Mik.,L. huidobrensis (Blanchard),L. sativae Blanchard,L. trifolii (Burgess) etL. trifoliearum Spencer. Le parasite se développe avec succès sur 8 familles de plantes et 16 genres. Les plantes-hôtes qui sont favorables au développement jusqu'à l'adulte des mineuses le sont également pour le développement du parasite. La durée moyenne du développement (de l'œuf à l'adulte, avecL. trifolii comme hôte) à 21°1, 26°7 et 32°2 C était pour les deux sexes, de 23, 14 et 14 jours respectivement. La longévité des fe melles nourries d'eau exclusivement était inversement proportionnelle à la température; la survie était significativement prolongée à 21°1 C (5,0 jours) comparativement à 26°7 C et 32°2 C (3,2 et 2,1 jours respectivement). L'adjonction de miel dans l'alimentation augmentait d'une manière significative la longévité des 2 sexes à toutes les températures. Les adultes femelles à qui l'on fournissait une moyenne journalière de 33 larves deL. trifolii avaient une descendance moyenne de 135 individus à la température constante de 26°7 C.C. parksi se nourrissait en moyenne de 3,7 larves de mineuse/jour durant les 11 jours de sa vie adulte.
    Notes: Abstract Biological studies withChrysocharis parksi Crawford, a parasite of agromyzid leafminers, were conducted.C. parksi successfully parasitized the following species in the genusLiriomyza Mik.,L. huidobrensis (Blanchard),L. sativae Blanchard,L. trifolii (Burgess), andL. trifoliearum Spencer. Successful parasite development was recorded from 8 plant families and 16 genera. Host plants which were suitable for leafminer development to the adult stage were also suitable for parasite development. Mean immature developmental period (egg to adult, usingL. trifolii as the host) at 21.1°, 26.7°, and 32.2° C was (for both sexes) 23, 14, and 14 days, respectively. Longevity of females provided only water was inversely related to temperature; significantly longer survival occurred at 21.1° C (5.0 days) compared to 26.7° C and 32.2° C (3.2 and 2.1 days, respectively). The addition of honey to the diet significantly improved longevity of both sexes at all temperatures. Adult female parasites which were provided an average of 33.0L. trifolii larvae per day produced an average of 135 offspring at a constant 26.7° C.C. parksi host-fed on ca. 3.7 leafminer larvae per day over an 11-day adult lifespan.
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    Patch-exploitation patterns in an egg parasite of elm leaf beetle (1987)
    Springer
    BioControl 32 (1987), S. 233-239 
    Details
    ISSN: 1573-8248
    Keywords: Pyrrhalta luteola ; Tetrastichus gallerucae ; spatial density dependence ; biological control ; Pyrrhalta luteola ; Tetrastichus gallerucae ; dépendance de la densité spatiale ; lutte biologique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Les œufs de la Galéruque de l'Orme,Pyrrhalta luteola (MULLER) sont déposés normalement en paquets visibles sous forme de plaques d'hôtes discrètes dans l'espace et dans le temps. L'analyse de plus de 800 plaques issues de trois localités du Nord de la Californie révèle que le nombre d'œufs/plaque varie de 2 à plus de 40 et que le parasite oophage importéTetrastichus gallerucae (FONSC) exploite une proportion relativement grande des plaques d'œufs à certaines périodes. La relation spatiale entre le parasitisme et le nombre d'œufs/plaque s'estime de 2 façons différentes: par les plaques exploitées uniquement ou par toutes les plaques combinées, qu'elles soient attaquées ou non. Le pourcentage de parasitisme est indépendant de la densité dans la plupart des cas. On suggère que les 2 méthodes d'analyse peuvent fournir des modèles qui son applicables dans la lutte biologique contre les ravageurs.
    Notes: Abstract Eggs of elm beetle,Pyrrhalta luteola (Muller), normally occur in masses which can be viewed as discrete host patches in space and time. Analysis of〉800 egg masses from 3 field sites in northern California revealed that the number of eggs/mass varied from 2 to〉40 and that the imported egg parasiteTetrastichus gallerucae (Fonsc.) exploited a relatively large proported of the egg masses at certain times. The spatial relationship between parasitization and number of eggs/egg mass was assessed in 2 ways-i.e., for exploited masses only and for all masses combined (exploited+nonexploited). Percent parasitization was density independent in most cases for both data sets. It is suggested that both methods of analysis can provide patterns which are relevant to biological control of insect pests.
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    Collections of natural enemies ofLeptinotarsa decemlineata [Coleoptera: Chrysomelidae] in Mexico, 1980–1985 (1987)
    Springer
    BioControl 32 (1987), S. 249-254 
    Details
    ISSN: 1573-8248
    Keywords: Leptinotarsa decemlineata ; biological control ; Mexico ; Oplomus ; Chrysomelobia labidomerae ; Edovum puttleri ; Leptinotarsa decemlineata ; lutte biologique ; Mexique ; Oplomus ; Chrysomelobia labidomerae ; Edovum puttleri
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Trois voyages ont été entrepris dans le centre du Mexique pour rechercher les ennemis naturels deLeptinotarsa decemlineata (Say) en 1980, 1983 et 1985. Dix-huit espèces d'ennemis naturels ont été trouvées associées aux 10 espèces deLeptinotarsa. Les pentatomides Asopine dominent dans les récoltes, suivis par les tachinaires parasites et les hémiptères et les coléoptères prédateurs. Les ennemis naturels peuvent jouer un rôle primordial dans la régulation des populations deLeptinotarsa au Mexique. Leur capacité d'adaptation aux climats septentrionaux est incertaine.
    Notes: Abstract Three trips were taken to central Mexico to search for natural enemies ofLeptinotarsa decemlineata (Say), in 1980, 1983, and 1985. 18 natural enemy species were found associated with 10 species ofLeptinotarsa. Asopine pentatomids dominate the collections, followed by tachnid parasites and hemipteran and coleopteran predators. Natural enemies may play a major role in regulating populations ofLeptinotarsa in Mexico. Their adaptability to northern climates is unclear.
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    Predation and parasitism of cotton leafworm eggs,Alabama argillacea [Lep.: Noctuidae] (1987)
    Springer
    BioControl 32 (1987), S. 241-248 
    Details
    ISSN: 1573-8248
    Keywords: Cotton leafworm ; Alabama argillacea ; biological control ; predation and predatism ; Noctuelle du coton ; Alabama argillacea ; lutte biologique ; prédation et parasitisme
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé L'identification et l'efficacité des arthropodes prédateurs et parasites intervenant dans la limitation naturelle des populations d'Alabama argillacea (Huebner) ont fait l'object d'études dans une culture de coton à Jaboticabal, Etat de São Paulo au Brésil. Les plantes ont été marquées au hasard et les œufs trouvés ont été indiqués par des flèches de ruban adhésif pour l'observation de la prédation et du parasitisme. Pour évaluer et identifier la faune des arthropodes sur le mètre linéaire contenant la plante marquée, des observations visuelles et des récoltes au moyen du D-Vac ® et du “beat sheet” ont été utilisées. Le taux moyen de prédation pendant la saison, en présence de 23,0 prédateurs par mètre linéaire a été de 50,6% et le parasitisme parTrichogrammatoidea sp. a été de 44,9% soit au total une réduction de 95,5% des œufs. Les espèces de prédateurs trouvés, ont été, en ordre décroissant:Pheidole sp. (Formicidae), Chrysso clementinae Petrunkewitch (Araneidae), Orius insidiosus Say. (Anthocoridae), Ceratocapsus marilieasis Carvalho & Fontes (Miridae) etHyperaspis festiva (Mulsant) (Coccinellidae).
    Notes: Abstract The identification and efficiency of arthropod predator and parasites related to natural control of cotton leafworm eggs,Alabama argillacea (Huebner), were studied in a cotton field, Jaboticabal, SP, Brazil. Plants were marked randomly and the eggs found on them were indicated by arrow tapes for predation and parasitism observations. To evaluate and identify the arthropod fauna in the row-meter containing the marked plant, visual countings and collections using D-Vac ® and “beat sheet” were used. The average predation rate during the season, in the presence of 23.0 predators per row-meter, was 50.6% and the parasitism byTrichogrammatoidea annulata was 44.9% totaling 95.5% of egg reduction. In decreasing order of abundance, the arthropod predators found were the antPheidole sp., the spiderChrysso clementinae Petrunkevitch, the hemipteraOrius insidiosus Say andCeratocapsus mariliensis Carvalho & Fontes, and the coccinellidHyperaspis festiva (Mulsant).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02373246
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  • 97
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    Selection on the male hemizygous genotype in arrhenotokous insects and mites (1987)
    Springer
    BioControl 32 (1987), S. 261-268 
    Details
    ISSN: 1573-8248
    Keywords: Aphytis ; arrhenotoky ; biological control ; haplo-diploidy ; selection ; Aphytis ; arrhénotoquie ; lutte biologique ; haplo-diploïdi ; sélection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Description / Table of Contents: Résumé Les Hyménoptères et les Acariens à reproduction arrhénotoque renferment beaucoup d'ennemis naturels importants. Ce système de reproduction offre l'occasion de sélection sur les mâles hémizygotes, avec les avantages afférents d'un génotype non masqué totalement exposé à la sélection, d'une fréquence augmentée de génotypes exprimant des gènes rares et d'une discrimination accrue de caractères dans les populations mâles produites par les femelles vierges. Une intensité de sélection amplifiée et une dérive génétique réduite peuvent offrir des avantages supplémentaires. La méthode est limitée aux caractères affichés par les mâles et peut réclamer des techniques intensives de laboratoire et une recherche d'espèce spécifique. On a montré que cette méthode est utilisable avecAphytis holoxanthus DeBach (Hym.: Aphelinidae), parasite important du Pou de Floride,Chrysomphalus aonidum (L.) (Hom.: Diaspididae).
    Notes: Abstract Arrhenotokously reproducing Hymenoptera and Acarina include many important natural enemies. This reproductive system offers the opportunity of selection on hemizygous (♂ ♂), with the attendant advantages of an unmasked genotype fully exposed to selection, in creased frequency of genotypes expressing rare genes, and enhanced discrimination of characters, in all-♂ populations produced by virgin (♀ ♀). Increased selection intensity and reduced genetic drift may offer additional advantages. The method is limited to characters displayed by (♂ ♂), and may require labor-intensive techniques and species-specific research. The method has been shown to be practicable withAphytis holoxanthus DeBach (Hymenoptera: Aphelinidae), an important parasite of the Florida red scale,Chrysomphalus aonidum (L.) (Homoptera: Diaspididae).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02373249
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  • 98
    Electronic Resource
    Electronic Resource
    Response of winter wheat to N-fertiliser: Quantitative relations for components of growth (1987)
    Springer
    Nutrient cycling in agroecosystems 12 (1987), S. 119-137 
    Details
    ISSN: 1573-0867
    Keywords: fertiliser ; nitrogen ; regression ; response ; winter wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Measurements were made of yield of dry matter, plant-N content, and the distribution of mineral-N down the soil profile in 10 fertiliser-N experiments. In one of them detailed measurements were made throughout growth. Rate of N-uptake by the crop was unaffected by the amount of mineral-N in the upper 90 cm of soil when it was above about 30 kg N ha−1. The %N in plants that received ample N-fertiliser declined with increase in plant mass according to a previously derived equation. During senescence there was an apparent loss of N from the crop. N-nutrition in the different experiments had little effect on the partition of assimilate between grain and straw. At harvest grain and straw weights were well related by a linear model which had the same gradient but different intercepts for each experiment. Grain %N was about four times greater than straw %N. Regression analysis supported the view that high evaporative conditions or temperatures during the growing period induced earlier harvest dates, less grain relative to straw, and a higher %N in the plant when ample N-fertiliser was applied but not when N-fertiliser was withheld. Other analyses indicated that cereal roots were generally unable to extract mineral nitrogen from the soil when the concentration was less than about 0.18 kg N ha−1 cm−1, that at low levels of N-nutrition the recovery of available inorganic-N from soil by the grain and straw was about 80%, and that the average mineralisation rates from early spring to shortly after harvest date varied between 0.22 and 0.88 kg N ha−1 d−1 from site to site.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01048913
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  • 99
    Electronic Resource
    Electronic Resource
    Effect of nitrogen, phosphorus and soil and crop residues management practices on maize (Zea mays L.) yield in ultisol of eastern Cameroon (1987)
    Springer
    Nutrient cycling in agroecosystems 14 (1987), S. 135-142 
    Details
    ISSN: 1573-0867
    Keywords: nitrogen ; phosphorus ; soil and crop residues management practices ; maize yield ; Plinthudult ; Cameroon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The shortening of fallow period in several areas in tropical Africa has reduced soil fertility and exposed soils to erosion and run-off. Fertilizer application and crop conservation practices are needeed to sustain high crop yield and to conserve the natural resource base for upland crop production in the continent. Field trials were carried out to evaluate the effect of fertilizer application and soil and crop residues management practices on yield of maize (Zea mays L.) planted on a Plinthudult soil at Bertoua, Eastern Cameroon. Maize yields increased significantly with nitrogen and phosphorus fertilizer application. Under the rainfall pattern prevailing in the area, the amount of nitrogen required for maximum yield was higher in the second season. On the other hand, the amount of phosphorus required for maximum yield appeared to decrease with time. The burning of crop residues and weeds prior to planting together with no-till practive gave higher yield of maize than other soil and crop residues management practices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01066606
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  • 100
    Electronic Resource
    Electronic Resource
    Effect of nutrient seed coating on the emergence of wheat and oats (1987)
    Springer
    Nutrient cycling in agroecosystems 14 (1987), S. 205-217 
    Details
    ISSN: 1573-0867
    Keywords: urea ; nitrogen ; phosphorus ; phenyl phosphorodiamidate ; ammonia ; toxicities ; germination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A series of experiments was conducted under controlled soil moisture and temperature conditions in a growth chamber to examine the effect of a range of nutrient seed coatings on the emergence to wheat (Triticum aestivum L. cv. Kite) and oats (Avena sativa L. cv. Blackbutt) sown in a coarse sandy loam soil. Final emergence of oats was not reduced by a coating containing 10 kg P ha−1 (as monocalcium phosphate [MCP]) whereas the same coating reduced wheat emergence by 15%. The emergence of both wheat and oats was severely reduced by urea coatings (supplying 10 kg N ha−1) to 33 and 13% respectively; this injury was lessened markedly by the inclusion of phenyl phosphorodiamidate (PPD) in the urea coatings at 1% (w/w) (emergence increased to 66 and 56% respectively). Low soil moisture (67% of field capacity [FC]) resulted in almost no emergence of wheat coated with urea (± bentonites of different pH). In soil at FC, the addition of bentonite of pH 5 (B5) to urea coatings permitted greater emergence (54%) than when bentonite of pH 9 (B9) was added (32%) which, in turn, permitted greater emergence than urea coating alone (10%). When PPD and bentonite (B5 or B9) were combined either singly or together with urea in seed coatings, PPD was more effective than either of the bentonites in reducing injury and masked the slight positive effect of B5. Coatings containing various combinations of N and P sources (at 3.6 and at 8 kg ha−1 respectively) all reduced the emergence of wheat compared to raw seed (91% emergence). When applied alone, MCP was least damaging (74%); the combination of MCP with ammonium sulfate (AS) caused somewhat more injury (68%) whilst combination with calcium nitrate (CN) caused most injury (29%). In contrast, CN alone caused relatively little damage (73%) whilst AS alone was more damaging (50%). There was no significant regression found between percentage emergence and either the calculated partial salt index or the pH of the nutrient coatings. Further work is needed to examine the mechanisms of injury due to nutrient seed coatings so that safe but effective formulations can be developed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01050665
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