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  • Solanum tuberosum L.
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  • 1
    facet.materialart.
    Unbekannt
    In:  Zoologische Mededelingen (00240672) vol.73, 1-10 (1999) p.131
    Publikationsdatum: 2007-01-23
    Beschreibung: The species of Encarsia Foerster (Hymenoptera: Aphelinidae) known from Egypt are revised. A total of 14 species are treated, including one new species. E. indifferentis Mercet, 1929, is synonymised with E. inaron (Walker, 1839). All species are fully described or diagnosed, and illustrated. Host records, and species-distributions outside Egypt, are given.
    Schlagwort(e): Egypt ; Encarsia ; Aleyrodidae ; Aphelinidae ; Diaspididae ; parasitoids ; biological control ; natural enemies ; 42.75
    Repository-Name: National Museum of Natural History, Netherlands
    Materialart: Article / Letter to the editor
    Format: application/pdf
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  • 2
    facet.materialart.
    Unbekannt
    In:  Zoologische Mededelingen vol. 73, 1-10, pp. 131-163
    Publikationsdatum: 2024-01-12
    Beschreibung: The species of Encarsia Foerster (Hymenoptera: Aphelinidae) known from Egypt are revised. A total of 14 species are treated, including one new species. E. indifferentis Mercet, 1929, is synonymised with E. inaron (Walker, 1839). All species are fully described or diagnosed, and illustrated. Host records, and species-distributions outside Egypt, are given.
    Schlagwort(e): Egypt ; Encarsia ; Aleyrodidae ; Aphelinidae ; Diaspididae ; parasitoids ; biological control ; natural enemies
    Repository-Name: National Museum of Natural History, Netherlands
    Materialart: info:eu-repo/semantics/article
    Format: application/pdf
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 257-266 
    ISSN: 1570-7458
    Schlagwort(e): host suitability ; acceptance ; biological control ; new associations ; Lepidoptera ; Pyralidae ; New World ; Old World ; stemborers ; Braconidae ; larval parasitoids ; Gramineae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The present study examined the acceptability and suitability of Old World stemborers (Chilo partellus and C. orichalcociliellus) for the development of New World parasitoids (Apanteles deplanatus and A. minator) and New World stemborers (Diatraea saccharalis and D. grandiosella) for the development of Old World parasitoids (Cotesia sesamiae, C. flavipes and C. chilonis). Results revealed that acceptance and suitability were high in old associations. In new associations, parasitoids accepted about 60% of the new association hosts. In addition, 10 out of 17 new associations were successful. Apanteles species appeared to be more physiologically host specific than Cotesia species. For example, two of four new association hosts were accepted by A. deplanatus and only one (D. saccharalis) was partially suitable for progeny development. Among the Cotesia species, Cotesia flavipes appeared to have a wider host range than the two other species. It attacked all hosts offered and successfully parasitized all but one (D. grandiosella). Diatraea saccharalis was accepted and was a suitable host for the development of all parasitoid species tested, whereas D. grandiosella was unsuitable for the development of four out of five parasitoid species tested. No clear pattern was observed as behavioral acceptance did not always agree with the pattern of physiological suitability. Implications of these findings for importation biological control of stemborers are discussed.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 91 (1999), S. 327-336 
    ISSN: 1570-7458
    Schlagwort(e): biological control ; in vitro rearing ; rearing techniques ; host selection
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract An artificial host egg was developed as a first attempt to improve the techniques for in vitro rearing of Trichogramma galloi Zucchi and T. pretiosum Riley (Hymenoptera, Trichogrammatidae). Plastic membranes (polyethylene, polypropylene and polystyrene) of different thickness were tested for their usefulness in manufacturing artificial eggs, using a thermal system to produce semi-spherical cupules on the plastic surface. These artificial eggs were filled with larval hemolymph of Helicoverpa zea (Boddie) (Lepidoptera, Noctuidae), and the optimal size of the artificial egg and density of females/artificial egg for the highest host acceptance (percentage of artificial eggs with at least one parasitoid egg) as well as the ideal level of parasitism (eggs/artificial egg) were determined. High-density polyethylene 7–8 and 9–10 μm thick resulted in the best acceptance and level of parasitization for both parasitoid species. Six females per artificial egg resulted in the best rate of parasitization for these parasitoids, although these data were not different when using 4 or 5 females of T. galloi. The size, shape and surface texture of the artificial eggs were found to provide enough cues to elicit parasitization behavior in Trichogramma females, since no chemical stimulus was provided.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1570-7458
    Schlagwort(e): Trichogramma spp. ; Helicoverpa armigera ; Chrysoperla carnea ; Portugal ; parasitism ; biological control ; non-target species
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Parasitism of two host species by five Trichogramma species (Hymenoptera, Trichogrammatidae) was studied in the laboratory. The host species were: i) the bollworm Helicoverpa armigera Hübner (Lepidoptera, Noctuidae), an important pest of many crops in the tropics and subtropics, and ii) one of its natural enemies, the lacewing Chrysoperla carnea Stephens (Neuroptera, Chrysopidae), a predator often used as a biological control agent. The proportion of H. armigera eggs parasitized from the total number of parasitized hosts differed between Trichogramma species. The average number of parasitized eggs per female in 24 h by Trichogramma pintoi and T. bourarachae was 10 of H. armigera and about 0.5 of C. carnea. For the other three Trichogramma species (T. cordubensis, T. evanescens and T. turkestanica) these averages varied from 6 to 11 H. armigera eggs and from 3 to 4 C. carnea eggs. Total adult offspring production, contacts with hosts, secondary clutch size and sex-ratio of each Trichogramma species were determined as well. The results show that sympatric Trichogramma may parasitize target and non-target species in different proportions. If this difference corresponds to the field situation, simple laboratory tests could be performed to select not only efficient biogical control agents, but also species which are the least detrimental to non-target hosts.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 92 (1999), S. 21-28 
    ISSN: 1570-7458
    Schlagwort(e): host feeding ; host paralysis ; oviposition ; pre-oviposition phase ; Hypothenemus hampei ; Scolytidae ; biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of the density of the coffee berry borer, Hypothenemus hampei (Coleoptera: Scolytidae) on reproductive and host-feeding behaviours of the parasitoid Cephalonomia stephanoderis (Hymenoptera: Bethylidae) was evaluated under laboratory conditions. The number of hosts used for oviposition was density-dependent at low host density. Beyond a density of six hosts/day, the oviposition rate reached a maximum of 1.2 eggs/day due to egg limitation. Cephalonomia stephanoderis females responded to increasing host availability with a linear increase in host feeding. Overall, parasitoids killed more coffee berry borers by feeding and paralysis than by parasitism. At low host density, the pre-oviposition phase was extended, oogenesis was delayed, more males were produced, and host feeding occasionally occurred concurrently with oviposition. We suggest that the efficacy of C. stephanoderis as a biological control agent depends on seasonal variations in host density. Inoculative vs inundative releases in coffee plantations are discussed in relation to the abundance of the coffee berry borer during the fructification and interharvest periods.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 91 (1999), S. 449-457 
    ISSN: 1570-7458
    Schlagwort(e): Schizaphis graminum ; Aphelinus asychis ; aphid ; parasitoid ; natural enemy ; biological control ; greenbug ; host selection ; plant volatile
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Aphelinus asychis (Walker) can be valuable as a biocontrol agent of the aphid, Schizaphis graminum (Rondani), a major pest on grain crops in the United States. This study reports the wind tunnel, and olfactometric responses of this parasitoid to the host (aphid), plant (sorghum), and host-plant complex (aphid-infested sorghum). In addition, the parasitoids' response to malathion-treated plants is also presented. The goal of the present study was to test the hypothesis that volatiles associated with the host attract natural enemies, as reported in cases of many hymenopterous parasitoids, and also to learn about the effects of insecticides on these parasitoids. In wind tunnel studies, these parasitoids moved upwind in the direction of the host-infested plant. There was no direct flight observed, however, these parasitoids were observed to hop and jump, and sometimes walk to their host. In the olfactometer experiments, we found that A. asychis is attracted to host-plant complex. The parasitoids' response to malathion in the olfactometer suggested that a malathion formulation when applied to plants can lure these beneficials, thus providing new insight into the ongoing task of integrating chemical and biological control of insect pests.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 267-273 
    ISSN: 1570-7458
    Schlagwort(e): Macrolophus caliginosus ; mirid bug ; life table ; longevity ; fecundity ; development time ; mortality ; sex ratio ; oviposition period ; intrinsic rate of increase ; spider mite ; Tetranychus urticae ; tomato ; biological control ; glasshouse pests
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The life table characteristics of the polyphagous mirid Macrolophus caliginosus Wagner (Heteroptera: Miridae) preying on various stages of Tetranychus urticae Koch (Acari: Tetranychidae) with tomato as host plant were described at 22 °C. The following average parameters were obtained: Female longevity: 28.7 days; fecundity: 0.7 eggs/female/day; egg mortality: 2.6%; pre-oviposition period: 5.5 days; oviposition period: 18.1 days; post-oviposition period: 3.2 days; juvenile development time: 26.8 days; juvenile mortality: 34.9%; and sex ratio (♀/(♀+♂): 0.46. Life table parameters were estimated as net reproduction rate (R 0): 6.15; intrinsic rate of increase (r m): 0.031 day−1; finite rate of increase (λ): 1.032; mean generation time (T c): 58.17 days; and doubling time (T 2) 22.2 days. The parameters obtained were in accordance with those reported for M. caliginosus fed on another mite species (T. turkestani Ugarov & Nikolski (Acari: Tetranychidae)). However, compared to the performance of M. caliginosus fed on common glasshouse insect pests, a diet consisting of only mites appeared to be inferior. However, being a voracious predator, M. caliginosus may be a valuable addition to existing methods of mite control.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 92 (1999), S. 73-82 
    ISSN: 1570-7458
    Schlagwort(e): biological control ; food web interactions ; volatiles ; Phytoseiidae ; predatory bugs ; thrips ; predator-predator interactions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Arthropods use odours associated with the presence of their food, enemies and competitors when searching for patches. Responses to these odours therefore determine the spatial distribution of animals, and are decisive for the occurrence and strength of interactions among species. Therefore, a logical first step in studying food web interactions is the analysis of behaviour of individuals that are searching for patches of food. We followed this approach when studying interactions in an artificial food web occurring on greenhouse cucumber in the Netherlands. In an earlier paper we found that one of the predators of the food web, the predatory mite Phytoseiulus persimilis Athias-Henriot, used to control spider mites, discriminates between odours from plants with spider mites, Tetranychus urticae Koch, and plants with spider mites plus conspecific predators. The odours used for discrimination are produced by adult prey in response to the presence of predators, and probably serve as an alarm pheromone to warn related spider mites. Other predator species may also trigger production of this alarm pheromone, which P. persimilis could use in turn to avoid plants with heterospecific predators. We therefore studied the response of the latter to odours from plants with spider mites and 3 other predator species, i.e. the generalist predatory bug Orius laevigatus (Fieber), the polyphagous thrips Frankliniella occidentalis and the spider-mite predator Neoseiulus californicus (McGregor). Both olfactometer and greenhouse release experiments yielded no evidence that P. persimilis avoids plants with any of the 3 heterospecific predators. This suggests that these predators do not elicit production of alarm pheromones in spider mites, and we argue that this is caused by a lack of coevolutionary history. The consequences of the lack of avoidance of heterospecific predators for interactions in food webs and biological control are discussed.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 51-61 
    ISSN: 1570-7458
    Schlagwort(e): Metarhizium anisopliae ; Atta sexdens rubropilosa ; leaf-cutting ants ; biological control ; social homeostasis ; entomopathogenic fungus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract There is growing interest in the use of entomopathogenic organisms to control leaf-cutting ants (Hymenoptera: Formicidae: Attini). However, the way leaf-cutting ants react as a colony to biohazards is poorly understood. We investigated the effects of Metarhizium anisopliae (Metschnikoff) (Deuteromycotina: Hyphomycetes) applied to the foraging arenas of mini-nests (queenless sub-colonies) of the leaf-cutting ant Atta sexdens rubropilosa (Forel). Dry spores were applied either alone or mixed with citrus powder, at 0.5 g or 0.05 g per mini-nest. The spores were removed four days after application, and all dead ants removed every three days. Ant numbers near the Metarhizium increased as the ants attempted to clean up the biohazard. The ants attempted to place the spores in piles, which they then covered over with other material. They were able to deal with the low doses in this way, but the high doses overwhelmed them. All treated mini-nests suffered increased ant mortality during the first ten days after application. This mortality was particularly high in the media worker caste which had played the major role in attempting to clean up the spores. Foraging activity decreased, as did the health of the fungus gardens. The mini-nests exposed to the low dose of spores mixed with citrus powder then recovered fully. The health of the other treated mini-nests declined gradually until around 26 days after application, when they began deteriorating sharply. However, the decline of these mini-nests after day 26 was not due directly to the pathogenic action of the Metarhizium, nor to the initial ant mortality it had caused. The results suggest that the social stress caused by even such a short-lived Metarhizium epizootic was sufficient to cause the decline and ultimate death of the mini-nests. This has important implications for the control of leaf-cutting ants. It also demonstrates how important the social homeostasis of the colony is to leaf-cutting ants.
    Materialart: Digitale Medien
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  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 103-107 
    ISSN: 1570-7458
    Schlagwort(e): learning ; Orius majusculus (Reuter) ; Heteroptera ; Anthocoridae ; predator ; biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
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  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 90 (1999), S. 183-189 
    ISSN: 1570-7458
    Schlagwort(e): Hymenoptera ; Aphelinidae ; Platygasteridae ; Hemiptera ; Aleyrodidae ; whiteflies ; Bemisia ; Amitus bennetti ; parasitoid ; biological control ; life history ; instar preference ; oviposition behaviour
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Amitus bennetti Viggiani & Evans (Hymenoptera: Platygasteridae) is a recently described parasitoid of the silverleaf whitefly, Bemisia argentifolii Bellows & Perring (Homoptera: Aleyrodidae). Behaviour and life history of the parasitoid are described. The first nymphal instar of B. argentifolii is preferred by the parasitoid, but the 1st through 4th instar may be parasitised. Females first investigate hosts with their antennae, then walk over the host, and eventually step with their front legs on the leaf and insert their ovipositor inside the host facing away from the host, while the hind legs are still on the host. The time from encounter to oviposition (=latency to oviposition) is shortest on the 1st instar. Oviposition duration (mean=39 s) comprises 50% of the handling time. Development time from egg to adult decreases from 72 days at 15 °C to 42 days at 20 °C to 28 days at 25 °C. We estimate that 400 degree days is required for development, with a development threshold of 10 °C. Adult longevity in the absence of hosts was 29, 26 and 19 days and with hosts present 8, 8 and 5 days at 15, 20 and 25 °C, respectively. Amitus bennetti is proovigenic and oviposits most eggs shortly after adult emergence. During the first day of their adult lives females laid 1, 31 and 49 eggs at 15, 20 and 25 °C, respectively. Compared with other parasitoid species, the development time of A. bennetti is very long, and the implications of this for management of B. argentifolii are discussed.
    Materialart: Digitale Medien
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  • 13
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 77-86 
    ISSN: 1570-7458
    Schlagwort(e): Acari ; behaviour ; biological control ; Gerbera jamesonii ; herbivore induced synomones ; infochemicals ; indirect defence ; Phytoseiidae ; semiochemicals ; terpenoids ; Tetranychus urticae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Jasmonic acid (JA) is a plant hormone that is involved in the induction of plant defence in response to herbivore attack. We studied the effect of exposure of gerbera leaves to JA on indirect plant defence, i.e. attraction of natural enemies of herbivores. Treatment of gerbera leaves with JA or feeding damage by the herbivorous spider mite Tetranychus urticae, both induced the production of a complex odour blend that attracts the predatory mite Phytoseiulus persimilis. This phytoseiid predator is a very effective biological control agent of the spider mite T. urticae. Comparison of headspace composition of gerbera leaves exposed to either JA or T. urticae revealed a large degree of resemblance, but some quantitative and qualitative differences were recorded. The major chemical group in both treatments is formed by the terpenoids which quantitatively comprised up to 80% of the total odour blend. These terpenoids included (E)-4,8-dimethyl-1,3,7-nonatriene, (E)-β-ocimene and linalool that are known to attract P. persimilis. Aldehydes, alcohols, esters and ketones, together with nitrogenous compounds formed the remaining constituents of the odour blend. The induction of predator attractants in plants by JA may be applied in biological control programs, which is discussed in this paper.
    Materialart: Digitale Medien
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  • 14
    ISSN: 1573-0832
    Schlagwort(e): biological control ; compatible solutes ; Epicoccum nigrum ; polyols ; solid substrate fermentation ; water activity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Epicoccum nigrum conidia were produced by solid fermentation on wheat grains (cv. Rendeveaux and Brigadier) at different water activities (aw). Conidial production was highest at high aw(0.996) than at reduced aw (0.98). However, conidial production at reduced aw was improved when the aw of the substrate was adjusted with a mixture of glycerol and water. Maximum levels ofconidiation were 7–11 × 106 conidia g−1 grain. The aw of the solid substrate affected the pattern of accumulation of compatible solutes in the conidia. Mannitol was the main polyol in all conidialtypes. However, the amounts of mannitol were higher in conidia produced at high aw. At reduced aw the conidia of E. nigrum accumulated moreglycerol, which is more efficient in the osmorregulation proccess than mannitol. Arabitol accumulated in low amounts, specifically in conidia produced at the lower aw, on cv. Rendeveaux but not on cv. Brigadier. Trehalose was detected in higher amounts in cv. Rendeveaux than in cv. Brigadier, andthe amounts were higher in conidia produced at high aw. A significant amount of endogenous solutes was detected in the washing liquid used for the separation of the conidia.
    Materialart: Digitale Medien
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  • 15
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 4 (1999), S. 127-143 
    ISSN: 1572-9745
    Schlagwort(e): wheat ; stored-grain ; integrated pest management ; aeration ; biological control ; grain sampling ; insect monitoring ; modeling ; area-wide IPM
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Management of stored-grain insect pests by farmers or elevator managers should be based upon a knowledge of the grain storage environment and the ecology of insect pests. Grain storage facilities and practices, geographical location, government policies, and marketing demands for grain quality are discussed as factors influencing stored-grain insect pest management decisions in the United States. Typical practices include a small number of grain samples designed to provide grain quality information for segregation, blending and marketing. This low sampling rate results in subjective evaluation and inconsistent penalties for insect-related quality factors. Information on the efficacy of insect pest management practices in the United States, mainly for farm-stored wheat, is discussed, and stored-grain integrated pest management (IPM) is compared to field-crop IPM. The transition from traditional stored-grain insect pest control to IPM will require greater emphasis on sampling to estimate insect densities, the development of sound economic thresholds and decision-making strategies, more selective use of pesticides, and greater use of nonchemical methods such as aeration. New developments in insect monitoring, predictive computer models, grain cooling by aeration, biological control, and fumigation are reviewed, their potential for improving insect pest management is discussed, and future research needs are examined.
    Materialart: Digitale Medien
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  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 4 (1999), S. 21-37 
    ISSN: 1572-9745
    Schlagwort(e): carrot weevil ; IPM ; Anaphes spp. ; biological control ; ecology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The carrot weevil, Listronotus oregonensis (LeConte) (Coleoptera: Curculionidae) is a major pest of carrots in northeastern North America. The females oviposit in the leaf petiole and the developing larvae make tunnels in the carrot roots. Exclusive reliance on chemical control and the poor control obtained, prompted, in the early 1980s, research on the ecology and physiology of the pest and its natural enemies. Carrot weevil females start their oviposition by 147±9 DD7°C but they oviposit only in carrots past the 4 true-leaf-stage. As a result, oviposition is delayed, and damage reduced, in late-sown carrots. Monitoring carrot weevil adults in the spring with either carrot root sections or wooden plate traps enables growers to apply control treatments only if the population density justifies it. Egg parasitoids of the genus Anaphes (Hymenoptera: Mymaridae) are the most important natural enemies and they account, in untreated plots, for up to 80% mortality. Their effectiveness could be improved by managing field borders to establish secondary host species. An IPM programme was developed in the 1980s based on the research results obtained and, through regular monitoring, has achieved a substantial decrease in pesticide use.
    Materialart: Digitale Medien
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  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 4 (1999), S. 39-52 
    ISSN: 1572-9745
    Schlagwort(e): Scapteriscus ; Neocurtilla ; Gryllotalpa ; biological control ; turf ; pastures ; vegetables
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract There are at least 70 species of mole crickets (Orthoptera: Gryllotalpidae). Some are rare, others are innocuous, and a few are important pests. These soil-dwelling pests damage underground parts of a long list of cultivated plants. Although tillage and flooding are used successfully in some situations to bring these pests to the soil surface and expose them to vertebrate and other predators, chemical pesticides are widely used against them. Knowledge of their life history is used to time application of chemical treatments to save money, but is not used as widely as it might be. Classical biological control has been used against immigrant mole crickets in Hawaii, Puerto Rico, and the southern USA. In Florida, three Scapteriscus species from South America cause major damage to pastures and turf and are targets of a classical biological control program. Population levels of two of the pest species have been reduced substantially in Florida by establishment of a tachinid fly (Ormia depleta) and a steinernematid nematode (Steinernema scapterisci) from South America. The nematode also functions as a biopesticide. Managers of pastures and turf in Florida have thus far derived benefit from these classical biological control agents without understanding their function: use of chemicals is reduced when mole cricket populations are lower due to action of these organisms. Future enhancement of the action of O. depleta and of a sphecid wasp (Larra bicolor, which also was introduced from South America) probably will demand deliberate planting of nectar sources for adults of these biological control agents, and the advantage will be to managers who adopt such a strategy. Chemical pesticide use is strongly promoted by a large chemical industry, whereas biopesticidal use has thus far been little promoted and sales have been few. Even managers who do not change their simple strategy of pesticide use in response to damage by mole crickets, and have no knowledge of the differing life cycles of the three Scapteriscus species or of the presence and action of the classical biological control agents, will derive benefit as these biological control agents (and a predatory beetle which has not yet been released) increase their distribution.
    Materialart: Digitale Medien
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  • 18
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 4 (1999), S. 97-126 
    ISSN: 1572-9745
    Schlagwort(e): agriculture ; biological control ; campaign ; chemosterilent ; commensal ; control methods ; economics ; environmental and cultural methods ; horticulture ; India ; pest management ; pre- and post-harvest crop losses ; poultry farms ; rodent ; rodenticide ; South Asia ; trapping
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Eighteen species of rodents are pests in agriculture, horticulture, forestry, animal and human dwellings and rural and urban storage facilities in India. Their habitat, distribution, abundance and economic significance varies in different crops, seasons and geographical regions of the country. Of these, Bandicota bengalensis is the most predominant and widespread pest of agriculture in wet and irrigated soils and has also established in houses and godowns in metropolitan cities like Bombay, Delhi and Calcutta. In dryland agriculture Tatera indica and Meriones hurrianae are the predominant rodent pests. Some species like Rattus meltada, Mus musculus and M. booduga occur in both wet and dry lands. Species like R. nitidus in north-eastern hill region and Gerbillus gleadowi in the Indian desert are important locally. The common commensal pests are Rattus rattus and M. musculus throughout the country including the islands. R. rattus along with squirrels Funambulus palmarum and F. tristriatus are serious pests of plantation crops such as coconut and oil palm in the southern peninsula. F. pennanti is abundant in orchards and gardens in the north and central plains and sub-mountain regions. Analysis of the information available on the damage and economic losses caused by rodents in rice, wheat, sugarcane, maize, pearl millet, sorghum, oil seed, legume and vegetable crop fields, horticulture and forestry, poultry farms, and rural and urban dwellings and storage facilities clearly shows that chronic damage ranging from 2% to 15% persists throughout the country and severe damage, sometimes even up to 100% loss of the field crop, is not rare. Several traditional and modern approaches and methods of rodent control are being used. The existing knowledge of the environmental, cultural, biological, mechanical and chemical methods of rodent control in India is reviewed. Considerable variations exist in the susceptibility of the pest species to different methods, particularly to rodenticides and trapping, their field applicability, efficacy and economics in different crops, seasons and geographical regions, behavioural responses of the pest species to these methods in different ecological conditions and their adoption by farmers in different regions of India. Environmental and cultural techniques, such as clean cultivation, proper soil tillage and crop scheduling, barriers, repellents and proofing which may reduce rodent harbourage, food sources and immigration have long lasting effects but are seldom adopted. However, their significance in relation to normal agricultural practices, intensification and diversification are discussed. Rodenticides, which provide an immediate solution to the rodent problem, form the major component of rodent control strategies in India. Poison baiting of rodents with zinc phosphide and burrow fumigation with aluminium phosphide are common in agricultural fields and recently Racumin (coumatetralyl) and bromadiolone have been introduced for the control of both agricultural and commensal rodent pests in India. Methods and timings of campaigns and successes and problems in implementation of rodent control are also reviewed.
    Materialart: Digitale Medien
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  • 19
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 4 (1999), S. 307-312 
    ISSN: 1572-9745
    Schlagwort(e): microbial control ; biological control ; biopesticide ; mycopesticide ; Metarhizium ; Beauveria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Microbial control agents generally kill insects more slowly than chemical pesticides, and fast-moving migratory pests may not at first sight appear to offer the most promising targets for microbial control. Operators responsible for control may need to have recourse to chemical control agents. Nevertheless, there are many occasions when pests breed and feed outside the crop and a microbial control agent can be used. Similarly, immature stages may cause little damage and early treatment in the crop can avoid damage. Microbial control agents are particularly likely to be favoured if the pest breeds in a conservation area, and if a publicly-accountable agency is responsible for control. Other key points of importance are the IPM context, in particular detection, planning and forecasting of outbreaks and the role of natural enemies. With these points in mind, we identify several locust and grasshopper systems where microbial control is becoming established; additionally, Sunn pest of wheat and Armyworm are identified as promising situations forbreak microbials.
    Materialart: Digitale Medien
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  • 20
    ISSN: 1432-203X
    Schlagwort(e): Key words Ethylene inhibition ; Germplasm conservation ; In vitro conservation ; Minimal growth ; Potato ; Silver thiosulfate ; Solanum tuberosum L. ; Tissue culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  Efficacy of silver thiosulfate (STS) in reducing ethylene-induced culture abnormalities during minimal growth conservation of microplants was studied in seven potato (Solanum tuberosum L.) genotypes. Different concentrations of STS (0, 1.5, 3.0, 4.5, 6.0, 7.5 and 9.0 μg ml–1) were tested in minimal growth medium based on MS medium supplemented with 20 g l–1 mannitol and 40 g l–1 sucrose. STS improved the microplant growth and reduced the culture abnormalities during prolonged maintenance of potato shoot cultures in vitro. The beneficial effect of STS was most prominent for number of green leaves per microplant and leaf senescence. After 16 months of storage, desirable microplant growth was observed in cultures conserved in medium containing 6.0–9.0 μg ml–1 STS. The profile of the peroxidase isozymes of conserved cultures did not show any apparent genetic variation due to the presence of STS in the conservation medium.
    Materialart: Digitale Medien
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  • 21
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 25 (1999), S. 1555-1565 
    ISSN: 1573-1561
    Schlagwort(e): Yeasts ; Botrytis cinerea ; apple ; volatiles ; gray mold ; biological control ; fungal interaction ; acetate esters
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The fungus, Botrytis cinerea, causes decay in apples in postharvest storage. Conidia of B. cinerea on polycarbonate membranes were incubated on filter paper disks saturated with water or suspensions of yeasts (2 × 106 CFU/filter) and then exposed for 24 hr at 22°C to 0–16 μl of ethyl, butyl, or hexyl acetates injected into the headspaces of 500-cc glass jars. Germination of conidia was increased by exposure to 4–16 μl of ethyl acetate compared to the no-ester controls. Conidia were stimulated to germinate by 4 μl of butyl acetate and 8 μl of hexyl acetate, but greater volumes were toxic to germination. The yeasts Cryptococcus laurentii and Sporobolomyces roseus were more effective at reducing the stimulatory effect than Saccharomyces cerevisiae. Acetate esters also stimulated germination of conidia on polycarbonate membranes on apples inside jars. Cryptococcus laurentii or S. roseus suppressed this effect more than S. cerevisiae. Germination of conidia on a membrane on water inside a 3.9-liter jar containing an apple was 2.5-fold greater than the no-apple control. Butyl acetate increased Botrytis infection of apple wounds. Butyl and hexyl acetate were detected by GLC in the headspace of Golden Delicious apples. Results indicated that some acetate esters produced by apple stimulated germination of B. cinerea conidia, and this effect was suppressed by yeasts.
    Materialart: Digitale Medien
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  • 22
    ISSN: 1871-4528
    Schlagwort(e): Solanin ; Chaconin ; Magnesium ; Kalium ; Stickstoff ; Solanum tuberosum L. ; Phytophthora infestans ; Feldversuch
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Beschreibung / Inhaltsverzeichnis: Summary Field experiments were carried out for three years to study the effect of various magnesium, potassium and nitrogen fertilization rates on two medium-early edible potato cultivars. Additionally, one of the experimental areas was sprayed againstPhytophthora infestans to ascertain the effect of fungicides on the content of total glycoalkaloids (TGA) in potato tubers after harvest and after six months of storage. The applied fungicide treatments increased total glycoalkaloids (TGA) of potato tubers (Fig. 4). Fertilization with mineral nitrogen caused different reactions in both cultivars. There was a tendency for cv. Beryl to accumulate more glycoalkaloids with increasing nitrogen fertilization rates, while the opposite was observed for cv. Mila (Fig. 7). Fertilization with potassium and magnesium did not affect the results. On the basis of these results there was no conclusive evidence that the TGA content in the tubers was dependent on cultivar or on the weather during the growing season (Figs 1,2 and 3). The TGA content increased during storage, independently of previous treatments, (Figs 4–7).
    Notizen: Zusammenfassung Es wurden Feldversuche in drei Jahren mit zwei Speisekartoffelsorten, verschiedenen Mengen an Mineraldüngern und der Anwendungen eines Pflanzenschutzmittelns gegenPhytophthora infestans angelegt. Die Knollen wurden direkt nach der Ernte sowie nach einer sechsmonatigen Lagerung auf Glykoalkaloidgehalt untersucht. Zwischen den Sorten treten statistisch gesicherte Unterschiede im Gehalt an Glykoalkaloiden auf. Die Anwendung von Pflanzenschutzmitteln während der Vegetation erhöht den Gesamtgehalt an Glykoalkaloiden (TGA) in den Kartoffelknollen kurz nach der Ernte. Eine variierte Mineraldüngung hat keinen statistisch signifikanten Einfluss auf den TGA-Gehalt in den Proben kurz nach der Ernte, N- und K-Düngung verändern diesen jedoch im Laufe der Lagerung. Unabhängig von den übrigen Bedingungen erhöht sich der TGA-Gehalt in diesem Versuch während der Lagerung im Mittel von 5,8 auf 7,7 mg/100g Frischsubstanz.
    Materialart: Digitale Medien
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  • 23
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 601-606 
    ISSN: 1871-4528
    Schlagwort(e): growth regulator ; sucrose ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Ancymidol-induced in vitro tuberisation under different photoperiodic regimes (dark, SD=8 h, LD=16 h) and sucrose concentrations (2, 4, 6 and 8%) in cv. Jaerla (early) and cv. Baraka (late) was studied. Tuberisation was scored after 4 (dark) or 8 (light) weeks. Ancymidol significantly increased tuberisation under LD-SD for any sucrose concentration in both cultivars. Ancymidol also significantly increased tuberisation under LD-dark for 6% sucrose in both cultivars. Tuberisation in cv. Jaerla was significantly higher than in cv. Baraka for any photoperiodic treatment in the presence or absence of ancymidol with 4, 6 or 8% sucrose. The photoperiod SD-SD resulted in the higher level of tuberisation for any combination of sucrose, cultivar and ancymidol. The possible role of ancymidol is discussed.
    Materialart: Digitale Medien
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  • 24
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 611-617 
    ISSN: 1871-4528
    Schlagwort(e): dormancy ; potato ; losses ; Solanum tuberosum L. ; seed potato production
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Microtubers can be stored longer, transported and handled easier than plantlets, but they have some disadvantages related to long dormancy. Dormancy, number of sprouts per tuber and loss of microtubers under different storage temperatures were studied. Microtubers of four genotypes originated from different tuberization treatments (photoperiod combinations) were observed. We found that dormancy depended on cultivar and — in some cases — on the photoperiod treatment applied during tuberization. Generally, the dormacy was long and was greatly elongated by low storage temperature. One of the photoperiod treatments shortened while the other treatment prolonged the rest-period compared to the control, maybe due to a change in temperature accompanying the change in daily light (photoperiod combination). Besides, these treatments affected the number of sprouts per tuber. There was no significant difference in duration of dormancy between different tuber-size groups, but the loss increased significanctly with a decrease in tuber size. Based on this information we can use microtubers more effectively in the seed potato production programme.
    Materialart: Digitale Medien
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  • 25
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 101-105 
    ISSN: 1871-4528
    Schlagwort(e): late blight ; testing methods ; electrolyte leakage ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The resistance of ten potato cultivars (Agria, Ajax, Désirée, Liseta, Kennebec, Majestic. Monalisa, Prima, Spunta and Tonda di Berlino) toPhytophthora infestans was analyzed in vitro using 8 fungal strains. An assay based on electrolyte leakage was used for screening leaves and tuber tissues with fungal culture filtrates. With almost all cultivars the resistance of leaves did not correlate with the resistance of tubers. Cv. Ajax appeared the least susceptible in both leaf and tuber tests, while the cv. Prima was the most susceptible in tuber tests.
    Materialart: Digitale Medien
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  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 229-240 
    ISSN: 1871-4528
    Schlagwort(e): earliness ; planting season ; Mediterranean area ; off-season production ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary In Italy, the early potato cultivars of greatest economic significance are those grown off-season, in a cycle which is generally much earlier than the typical spring-summer cycle. Of the area given over to early potatoes in Italy, more than 90% is in the southern regions. The economic value of this production is due to its extraseasonality, which allows much of the early potato harvest to be sold on foreign markets. In Sicily, more than 5000 ha of potato are grown, with a high frequency of potato crops on small plots. Early potatoes are often rotated with various fruits and vegetables, and the length of the cycle is variable, from 100 to 140 days. Choosing the most suitable cultivar is the most complex aspect of early potato growing. Of the criteria used, tuber growth rate has shown most validity. In Sicily two cultivars are mainly grown: Sieglinde and the more recent but well-established Spunta. Agricultural techniques used for early potato cultivation vary depending on the area. An overview of the agronomic practices used in different areas is given in this paper.
    Materialart: Digitale Medien
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  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 381-395 
    ISSN: 1871-4528
    Schlagwort(e): agronomy ; breeding ; pathology ; physiology ; Solanum tuberosum L. ; storage ; utilisation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary This contribution presents highlights of the oral and poster presentations in the various sessions of the 14th Triennial Conference of the European Association for Potato Research, held in Sorrento, Italy, May 1999. It is based on the reports of the session chairpersons and the book of abstracts. The paper reports the progress made in many aspects of potato research, but also stresses the need for further collaborative work, especially in the fields of molecular physiology, marker assisted breeding, control of late blight, potato tuber moth and other pests and diseases, stress physiology and stress resistance, and sustainable cropping systems with both short and long cycle potato crops.
    Materialart: Digitale Medien
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  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 31-42 
    ISSN: 1871-4528
    Schlagwort(e): Solanum tuberosum L. ; tuberisation ; extensin ; acyl carrier protein thioesterase ; high mobility group protein ; gene expression ; plant development
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary In screening to isolate a full-length copy of a previously isolated cDNA clone, a further three cDNAs were also isolated from a library prepared from sub-apical swelling-stolon tissue of potato (Solanum tuberosum L.). Sequence analysis showed these clones to be similar to extensin-like protein genes, acyl carrier protein thioesterase genes and high mobility group protein genes, respectively. A further cDNA, isolated by subtractive hybridisation, was similar to a tomato cDNA previously isolated on the basis of its down-regulation following nematode infection. While all the newly isolated genes were expressed in swelling stolons, for most, maximal expression was seen to be in stem tissue. Possible roles for these genes in the development of potato plants are discussed, as is the significance of gene expression in stems and stolons to the process of tuberisation.
    Materialart: Digitale Medien
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  • 29
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 89-93 
    ISSN: 1871-4528
    Schlagwort(e): analysis ; HPLC ; β-glucoside ; 1,2-dihydro-3,6-pyridazinedione ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary The method of Vadukul (1991) for determining maleic hydrazide (MH) was modified and gave recoveries of free MH of 89%±4%. The values recorded on individual tubers ranged from 2–14 mg kg−1. Maleic hydrazide was evenly distributed throughout the tuber (peel, outer and inner flesh) but concentration increased slightly as tuber size increased. The concentration of free MH decreased from 7 to 3 mg kg−1 over the storage period of 5 1/2 months. Acid hydrolysis released substantial amounts of MH particularly from older potatoes (13 mg kg−1) compared with 6 mg kg−1 from new potatoes, implying that free MH is gradually converted to a bound form with time after treatment. No evidence was found for the presence of a β-glucoside of MH.
    Materialart: Digitale Medien
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  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 241-264 
    ISSN: 1871-4528
    Schlagwort(e): global distribution ; prospects ; diversification ; specialization ; price risk ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary We examine the changing character of supply and demand for potatoes over time and space with an eye towards implications for agricultural research. Diversification in consumption and specialization in production are our organizing themes. The foundation for comparative analysis is a map of the global distribution of potato growing area. We highlight the adverse impact of price risk on specialization and discuss several sources of uncertainty that condition the size but not the direction of major trends.
    Materialart: Digitale Medien
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  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 499-504 
    ISSN: 1871-4528
    Schlagwort(e): Solanum tuberosum L. ; microtuber ; liquid medium ; temporary immersion
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary CIRAD developed a new apparatus for plant tissue culture, using temporary immersion in a liquid medium. This apparatus was adapted to the microtuber production in potato. The procedure is as follows: single node cultivation on MS medium containing 30 g/l sucrose in the light for 2 weeks, induction of microtuberisation with 80 g/l sucrose over a 2 week period in the light, followed by a further 6 weeks in the dark. All experiments were performed at 20 °C. The basic vessel had a capacity of approximately 11;30 nodes were cultivated per vessel. Depending on the cultivars tested (Bintje, Ostara and Désirée) 47 to 115 microtubers were harvested per vessel. Between 30 and 60% of the microtubers weighted over 0.5 g and between 10 and 40% over 0.8 g. Sprouting is still under investigation. Preliminary results indicate that the dormancy period was relatively short and several stems were obtained per microtuber. These results seem to be better than those usually reported. Only one simple protocol has been tested and further improvements are probably easy to obtain.
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  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 585-591 
    ISSN: 1871-4528
    Schlagwort(e): Solanum tuberosum L. ; microtubers ; acetic acid ; propionic acid ; asscorbic acid ; salicylic acid ; acetylsalicylic acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Potato microtubers are usually induced in media containing growth regulatory, typically cytokinins and growth retardants. However, since these substances may imbalance the physiology of the cultured explants and cause adverse carry-over effects on the subsequent performance of the microtubers, the potential acid-induction of in vitro-mass tuberization was investigated as an alternative. For this purpose, a range of explant types (stolons, single-node or apex-containing multinodal sections), organic acids (acetic, propionic, ascorbic, acetylsalicylic or salicylic acid), and photoperiods (continuous dark, 8 or 16 h photoperiod) were established. Gellified medium or raft membranes on liquid medium were also tested. Although variations due to explant type, photoperiod, organic acid supplemented, and medium type were found, all organic acids tested under the different experiments caused tuberization. Multiple tuber formation or bigger tubers did not develop on multinodal explants. In terms of tuberization rate and mean tuber weight, gellified medium performed better than liquid medium with rafts. The recently established role of the salicylic and acetylsalicylic acids on tuberization is corroborated by our system. The results with the acetic, propionic and ascorbic acids show that in vitro hormone-free tuberization can be easily and rapidly achieved.
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  • 33
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 73-78 
    ISSN: 1871-4528
    Schlagwort(e): growth parameters ; K+/Na+ ratio ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Increased potassium (K) fertilization of saline soils has been implicated in alleviating salt stress in plants. We examined whether varying K concentrations in Murashige & Skoog (MS: 1962) basal medium could affect salt (NaCl) stress in micropropagated potatoes. Plantlets of cvs Sierra and Russet Burbank were evaluated after 1 month of growth in a medium containing 0. 40, or 80 mM NaCl and 6,20, or 30 mMK. The medium K was adjusted using KNO3 while total nitrogen was kept constant using NH4NO3. Growth parameters were less affected in Sierra than Russet Burbank, and roots were less affected than shoots, as the medium salinity increased. Tissue Na levels were greater when the medium K was 6 mM compared with 20 mM MS control. The medium K concentration 50% greater than MS control did not promote growth and did not limit tissue Na levels. While this should be confirmed by field assessment, our results suggest that while K deficiency promotes salt damage, its addition beyond the usual fertilizer recommendations is not beneficial in alleviating salinity stress.
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  • 34
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 607-610 
    ISSN: 1871-4528
    Schlagwort(e): seed production ; Greece ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Large scale, commercial production of potato minitubers, cvs Spunta, Jaerla and Kennebec, has been carried out in VITRO HELLAS S.A. since 1995, according to protocols based on in vitro methods. Apical meristems were cultured on MS medium supplemented with 1 μM IBA, 20 g/l sucrose and 6 g/l agar (pH 5.8). Subculture was carried out every 15 days. Multiplication rate was 4–5 per cycle. Self-rooted microplants were transferred into screen houses (200 plants/m2) in a mixture of peat and perlite 1∶1 (v/v). Cultivation period was 15 August to 15 November each year. During the period 1995–1997, the number of minitubers produced/plant was 2.07 for cv. Spunta, 1.85 for cv. Jaerla and 2.52 for cv. Kennebec and their average weights were 10.8 g, 10.9 g and 9.8 g, respectively. The percentage of minitubers〈10 mm in diameter was 2%, 50.1% were 10–20 mm and 47.9% were〉20 mm.
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  • 35
    ISSN: 1871-4528
    Schlagwort(e): cultivar ; virus diseases ; nematodes ; ground cover ; physiological age ; seed production ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary In Argentina, different areas are suitable for seed potato production: however, each has particular problems, mainly related to different pest and diseases. Tierra del Fuego Island is well isolated from traditional potato growing areas. Therefore, it was tested for its potential for seed production. The cultivars Achatt. Mailén INTA. Pampeana INTA and Spunta were grown in Río Grande, San Pablo and Ushuaia from 1991–1994. Nematode presence and aphid population dynamics were recorded. Average tuber yield ranged from 20.1–37.6 t ha−1. After three years PVY and PLRV remained low (0–1% for different cultivars and locations). Moreover, seed tubers obtained were physiologically young. Long days, early frosts and strong winds may limit tuber yield in some years. The island can be considered as an ecological “safe haven” and is very suitable to obtain healthy and physiologically adequate seed potatoes.
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  • 36
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 25-29 
    ISSN: 1871-4528
    Schlagwort(e): chlorpropham ; particulates ; dusts ; solvents ; ignition source ; explosive limits ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary An appraisal was undertaken of the key factors involved in explosion and combustion processes mainly associated with the fogging of chlorpropham formulations into potato stores. The key factors considered are source of ignition, solvents, explosive limits of solvents, the presence and atmospheric concentrations of particulate clouds and the role of particulate material in dust explosions. Also the sequence of events that takes place in a dust explosion, including critical concentrations of dust required to initiate the reactions involved and the particular relevance of the above events to the behaviour of chlorpropham fogs both at the time of application and when distributed throughout a store. The relevance of fine dust already present in the store to the initiation of explosions, particularly secondary explosions, which are considered to be a major cause of concern due to their severity, is also emphasised.
    Materialart: Digitale Medien
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  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 95-99 
    ISSN: 1871-4528
    Schlagwort(e): analysis ; HPLC ; filter paper model ; Diels-Alder reaction ; 1,2-dihydro-3,6-pyridazinedione ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary A method used for estimating extractable maleic hydrazide (MH) concentrations in fresh potato material, concentration range 5–17 mg kg−1, was found not to be suitable for processed potato products (10–33% recoveries) although, boiling potato pieces enhanced recovery by 20%. Each step of the determination was examined and a modified procedure developed with particular emphasis on the extraction of MH from the dried potato matrix, and the quality of the HPLC column used. Potato slices and model systems based on filter papers plus additives were used. Recoveries from fried potato slices were 74±6%. Based on the effect of glucose in reducing extractable MH recoveries, it is suggested that the remainder of the MH (20–25%) is converted into a conjugated structure on reaction with dehydrated sugar (Diels-Alder reaction).
    Materialart: Digitale Medien
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  • 38
    ISSN: 1871-4528
    Schlagwort(e): bioassay ; biological control ; blackleg ; green crop harvesting ; haulm killing ; skin damage ; wound protection ; Solanum tuberosum L
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Green crop lifting (GCL) for haulm killing was developed in The Netherlands and offers ideal conditions for controlling the blackleg pathogenErwinia carotovora subsp.atroseptica (Eca) by antagonists. Based on the use of mini-tubers or young tubers from field crops, two bioassays for wound protection were developed. GCL was simulated by artificially skinning or wounding tubers, inoculating the damaged skin with Eca, treating with antagonists and incubating in either potting compost or outside in field soil. Mainly fluorescent pseudomonads, pre-screened for in vitro antagonistic activity on agar and high soft rot reducing ability on tuber slices, were tested in the mini-tuber bioassay. Strains giving the highest degree of wound protection were further tested individually and in combination under field conditions in the young tuber bioassay. One individual strain and two combinations, resulting in reduction of contamination levels on skinned surfaces of 85% and between 60% and 70%, respectively, show good potential for biological control of blackleg.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 215-221 
    ISSN: 1871-4528
    Schlagwort(e): potato virus Y ; strain differentiation ; RFLP ; potato tuber necrotic ringspot disease ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary A procedure for differentiating PVYNTN from PVYN is described and is based on the unique cleavage of their respective PCR products with strain specific restriction endonucleases. The PCR products corresponding to the 5′ end of the N and NTN strains of PVY were cloned and sequenced, and a restriction map was constructed which included common enzymes that were used for the differentiation of PVYNTN. Unique, single cleavage of PCR products derived from the 5′ end of the PVYNTN genome by Nco I, and that of the N-strain of PVY by Bgl II restriction endonuclease were demonstrated. The specific digestion patterns in polyacrylamide gel were used for the unequivocal differentiation between the N and NTN strains of the virus. Both single and mixed infections were detected in field samples of potatoes using this procedure.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 40
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 265-277 
    ISSN: 1871-4528
    Schlagwort(e): wild species ; gene introgression ; heat stress ; drought stress ; frost stress ; biotic stresses ; off-season production ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary In the Mediterranean area the potato is a very important crop and can be cultivated throughout the year. However, tuber yields are generally much lower than those in Northern European countries. This is because the environmental and agro-economic conditions are different from those of Northern countries where most cultivars were developed. We feel that the objective for the “new Mediterranean potato” must be the availability of potato cultivars for each environment and for each planting season. Breeding programmes should focus on improving potato production within a specific agro-ecological Mediterranean area rather than improving crop production across areas. This paper reports aspects of potato breeding and physiology related to resistance to stress conditions in the Mediterranean area, with particular emphasis given to resistance to abiotic (heat, drought and frost) as well as biotic stresses. We also discuss the potential to produce seed tubers suitable for potato cultivation in the Mediterranean area.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 279-282 
    ISSN: 1871-4528
    Schlagwort(e): late blight ; mating types ; sexual recombination ; Solanum tuberosum L. ; diversification ; aggressiveness ; migration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Since the early 1980s and continuing through the end of the 20th century, potato late blight caused byPhytophthora infestans has become noticeably more problematic throughout the world. Exotic strains of the pathogen are largely responsible for the increased problems. The new strains were initially detected in Europe, but subsequently they have been detected in Asia, the Middle East, South America and North America. Populations in the Middle East and South America may represent secondary migrations from Europe. Several independent migrations have occurred such that migrant populations in North America are very different from those in Europe. Also, population structures ofP. infestans are different in different worldwide locations. In some locations the migrant strains are resistant to metalaxyl, but in other locations either migrant or indigenous strains may be resistant. In most locations, the migrant strains are more aggressive than the previous indigenous strains.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 42
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 42 (1999), S. 489-498 
    ISSN: 1871-4528
    Schlagwort(e): Solanum tuberosum L. ; microtubers ; nodal cuttings ; in vitro tuberization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary A tissue culture technique is described in which nodal cuttings ofSolanum tuberosum L. are induced to form usable microtubers in order to produce high health status of the seed potato genotypes cultivated in Switzerland.
    Materialart: Digitale Medien
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  • 43
    ISSN: 1871-4528
    Schlagwort(e): genes ; transgenic plants ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Continuing study of the potato plant's response to stressful conditions has led to the identification of a large number of plant genes whose expression, is regulated by external stimuli. Stress-induced genes can be broadly divided into functional or regulatory genes. To the first category belong genes encoding proteins or enzymes of plant metabolic pathway, of molecules involved in repairing cellular damages and/or indispensable for restoring a new cellular homeostasis compatible with the external conditions. The other class includes genes primarily involved in the perception and/or intracellular transduction of the stress signal, such as kinases, phosphatases or transcription, factors. The research objectives in the field of plant stress tolerance has recently evolved from a mere cloning and description of stress-induced genes to the design of the best strategy of producing transgenic plants tolerant to environmental constraints. It is well known that stress tolerance is a complex trait, requiring the coordinated regulation of a network of genes that act synergistically and additively. At best, manipulation of one single down-stream gene may contribute only partially to the tolerance of the transgenic plants. Recent studies have shown that it is feasible to regulate the level of expression of many down-stream stress-induced genes in a coordinated fashion by regulating the expression of genes encoding transcription factors able to bind DNA motifs in the promoter of stress-induced genes. However, the constitutive high level of expression of transcription factors often causes detrimental phenotypic effects. This drawback could be bypassed by putting genes for transcription factors under the control of inducible promoters. In this way, endogenous tolerance genes are activated only when the stress event occurs, minimizing the negative pleiotropic effect. Novel technology (reverse genetics, DNA microarrays, mRNA differential display, T-DNA tagging, complementation and over-expression of plant cDNA in yeast as model for cellular stress tolerance), improvement of genetic transformation techniques (multiple gene transfer, gene targeting by homologous recombination) as well as a better efficiency of foreign gene expression (discovery of plant promoters with cell-specific, tissue-specific, developmental stage-specific, and/or inducible patterns of expression) will give a tremendous impulse to produce stress tolerant commercial cultivars of the main crops through genetic engineering.
    Materialart: Digitale Medien
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  • 44
    ISSN: 1573-1464
    Schlagwort(e): Adelges tsugae ; biological control ; Diapterobates humeralis ; hemlock ; Japan ; natural enemies ; Picea spp. ; population dynamics ; predators ; Pseudoscymnus tsugae ; Tsuga spp.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Hemlock woolly adelgid, Adelges tsugae Annand (Homoptera: Adelgidae), is native to Japan where it is an innocuous inhabitant of Tsuga diversifolia Masters and T. sieboldii Carriere throughout their natural growing areas. Native adelgid populations are regulated by host resistance and natural enemies, in particular the oribatid mite, Diapterobates humeralis (Hermann) and the coccinellid beetle, Pseudoscymnus tsugae Sasaji and McClure. Invading populations of A. tsugae in western North America on T. heterophylla Sargent and T. mertensiana Carriere are mainly regulated by host resistance. However, invading populations in eastern North America attain damaging levels on T. canadensis (L.) Carriere and T. caroliniana Engelmann and are regulated mainly by weather and negative density-dependent feedback mechanisms related to host deterioration. Although A. tsugae is only passively dispersed by wind, birds, forest-dwelling mammals and humans, it is spreading at an alarming rate and is sufficiently cold hardy to threaten the existence of the two eastern hemlock species throughout their natural ranges. The current hope for suppressing invading populations of hemlock woolly adelgid in eastern North America lies with the exotic predator, P. tsugae. Extensive laboratory studies of the biology and predatory ability of P. tsugae revealed that it feeds on all life stages of its prey, that its multivoltine life cycle is well synchronized with that of the adelgid, and that it has great potential for biological control. We have reared and released nearly 130,000 adults of P. tsugae in forests in Connecticut, New Jersey and Virginia during the past four years. P. tsugae has reproduced, dispersed, overwintered and reduced densities of hemlock woolly adelgid by 47–88% in only five months on release branches at these sites. Current studies are investigating the long-term ability of P. tsugae to regulate invading populations of A. tsugae in eastern North America.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 45
    Digitale Medien
    Digitale Medien
    Springer
    Biological invasions 1 (1999), S. 301-311 
    ISSN: 1573-1464
    Schlagwort(e): Alliaria petiolata ; biological control ; garlic mustard ; invasions ; Lythrum salicaria ; monitoring ; Phragmites australis ; purple loosestrife
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The invasion of non-indigenous plants is considered one of the primary threats to rare and endangered species as well as to the integrity and function of North American ecosystems. However, many of the suspected negative ecosystem impacts are based on anecdotal evidence. For example, there is almost unanimous agreement among natural resource managers of the detrimental ecological impacts of species such as Lythrum salicaria (purple loosestrife), Phragmites australis (common reed) and Alliaria petiolata (garlic mustard) but convincing documentation is scarce. Experimental and theoretical ecology predicts large ecosystem impacts of the most widespread invasive species. However, it is difficult to prioritize control of species that occur at intermediate densities. Long-term monitoring before and during the invasion as well as before, during and after any control attempts can provide valuable ecological information. In particular, it is important to understand how changes in the abundance of species influence ecosystem properties and processes which, in turn, will help guide management decisions. Ideally, this monitoring has to go beyond 'simple’ impacts on plant communities, involve cross-disciplinary teams of scientists and should incorporate many different taxa and their interactions. Monitoring design and data collection should be sophisticated enough to allow statistically sound data analysis. The available information will be paramount in (1) developing new political and scientific guidelines in invasive species management, (2) helping resolve potential conflicts of interest and (3) helping change public attitudes regarding growth, sale, and control of non-indigenous species.
    Materialart: Digitale Medien
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  • 46
    Digitale Medien
    Digitale Medien
    Springer
    Biological invasions 1 (1999), S. 313-323 
    ISSN: 1573-1464
    Schlagwort(e): biological control ; biological invasions ; colonization ; Galerucella calmariensis ; Galerucella pusilla ; population ; establishment ; release size
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Introductions of biological control organisms offer a unique opportunity to experimentally study the process of invasion by exotic species. I used two chrysomelid beetles, Galerucella calmariensis and Galerucella pusilla, which are currently being introduced into North America for the biological control of purple loosestrife (Lythrum salicaria), to determine how the initial size of a release affects the probability that the introduced population grows and persists. I released both species into stands of their host plant at 36 sites scattered throughout central New York State using four release sizes: 20, 60, 180, and 540. I returned to these sites over the next 3 years to census the populations. For both species, the probability of population establishment increased with release size. Population growth rates also depended positively on release size. The implication from these results is that the demographic factors whose influence depends on population size or density such as demographic stochasticity, Allee effects, and genetics play important roles in the establishment of invading populations. A second set of releases was used to determine if it was at all possible for a single gravid female to found a population. Out of twenty individual females released, one female (a G. calmariensis) founded a population that persisted until the end of the study (3 generations).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 47
    Digitale Medien
    Digitale Medien
    Springer
    European journal of plant pathology 105 (1999), S. 123-137 
    ISSN: 1573-8469
    Schlagwort(e): Aureobasidium pullulans ; biological control ; Cryptococcus albidus ; grey mould ; Trichoderma harzianum
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The efficacy of Trichoderma harzianum T39 and the yeasts Aureobasidium pullulans and Cryptococcus albidus against Botrytis cinerea in cucumber and tomato was compared with chemical control. Four experiments were conducted in cucumber grown under different climatic conditions in The Netherlands, and two experiments were done in tomato both in the Netherlands and in Israel. T. harzianum and A. pullulans showed the most consistent control of B. cinerea, reducing stem lesions and death of plants by 40–100% in most cases. Control of stem lesions and subsequent wilting was generally better than control of symptoms on fruits. In some cases, the biocontrol agents were more effective than the broad-spectrum fungicide tolylfluanid and the selective fungicide iprodione. The climatic conditions did not strongly influence the efficacy of the biocontrol agents, but regression analysis showed that high temperature during the day and high vapour pressure deficit during the night reduced biocontrol efficacy. From the results, prospects for biocontrol of B. cinerea in greenhouse vegetables appear good under a range of conditions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 48
    Digitale Medien
    Digitale Medien
    Springer
    European journal of plant pathology 105 (1999), S. 95-101 
    ISSN: 1573-8469
    Schlagwort(e): bacteria ; biological control ; Chryseobacterium ; Flavobacterium ; grey mold ; Pseudomonas ; strawberries
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Most potential fungal antagonists have been identified only after exhaustive non-selective screening. Bacteria antagonistic to Botrytis cinerea were selected using a simple method based on techniques developed for trace enrichment studies, where a crude cell wall preparation from B. cinerea was used as a selective substrate and bacteria were isolated based on growth on cell wall agar media. Most of the 52 bacterial isolates that were obtained from the surface of ‘organically grown’ strawberry fruit and could grow on B. cinerea wall media in culture showed some ability to inhibit the growth of the fungus. Potato dextrose agar seeded with B. cinerea spores (104 ml−1) were challenged with each of these bacterial isolates at concentrations of 109 and 106 colony forming units ml−1. Eleven of the 52 isolates initially recovered, subsequently demonstrated strong antagonism in vitro and were selected for additional screening tests on strawberry fruit. All 11 isolates reduced grey mold rot incidence on fruit in storage. Three of the best isolates were tested in limited field trials, and also reduced grey mold rot on fruit under field conditions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 49
    Digitale Medien
    Digitale Medien
    Springer
    European journal of plant pathology 105 (1999), S. 201-210 
    ISSN: 1573-8469
    Schlagwort(e): in vitro interactions ; biological control ; rhizosphere
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Fusarium wilt diseases, caused by the fungus Fusarium oxysporum, lead to significant yield losses of crops. One strategy to control fusarium wilt is the use of antagonistic, root-colonizing Pseudomonas spp. It has been demonstrated that different strains of these bacteria suppress disease by different mechanisms. Therefore, application of a mixture of these biocontrol strains, and thus of several suppressive mechanisms, may represent a viable control strategy. A prerequisite for biocontrol by combinations of biocontrol agents can be the compatibility of the co-inoculated micro-organisms. Hence, compatibility between several Pseudomonas spp. strains, that have the ability to suppress fusarium wilt of radish, was tested in vitro on KB agar plates. Growth of P. fluorescens strain RS111 was strongly inhibited by Pseudomonas spp. strains RE8, RS13, RS56 and RS158, whereas a mutant of strain RS111 (RS111-a) was insensitive to inhibition by these strains. Strains RS111 and RS111-a only slightly inhibited some other strains. Suppression of fusarium wilt of radish in a potting soil bioassay by the incompatible combination of RE8 and RS111 was comparable to the effects of the single strains. However, disease suppression by the compatible combination of RE8 and RS111-a was significantly better as compared to the single strains. In contrast, the incompatible combination of RS56 with RS111 resulted in enhanced disease suppression as compared to the single strains. Increased disease suppression by combinations of RS13 or RS158 with RS111 or RS111-a was not observed. This indicates that specific interactions between biocontrol strains influence disease suppression by combinations of these strains.
    Materialart: Digitale Medien
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  • 50
    ISSN: 1573-1561
    Schlagwort(e): Allelopathy ; Allium tuberosum ; antibacterial activity ; biological control ; intercropping ; Lycopersicon esculentum Mill ; Pseudomonas solanacearum E. F. Smith ; root exudates ; soil-borne diseases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Tomato plants were grown alone or intercropped with Chinese chive plants, with or without the inoculation of Pseudomonas solanacearum. Chinese chive plants had no detrimental effects on the growth of tomato plants but significantly delayed and suppressed the occurrence of bacterial wilt of tomato. P. solanacearum population decreased faster in the soil grown with tomato alone than that in the soil grown with both tomato and Chinese chive. However, P. solanacearum population in bare soil was higher than that grown with Chinese chive. Root exudates of Chinese chive collected with a continuously trapping system were inhibitory to multiplication of P. solanacearum.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 51
    ISSN: 1573-1561
    Schlagwort(e): Herbivore-induced synomones ; infochemicals ; semiochemicals ; learning ; biological control ; prey location ; behavior ; Acarina ; Phytoseiulus persimilis ; Tetranychus urticae ; Gerbera jamesonii
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract When leaves of the ornamental crop Gerbera jamesonii are damaged by the spider mite Tetranychus urticae, they produce many volatile compounds in large quantities. Undamaged gerbera leaves produce only a few volatiles in very small quantities. In the headspace of spider mite-damaged gerbera leaves many terpenoids are present, comprising 65% of the volatile blend. In addition, a number of nitrogen containing compounds, such as oximes and nitriles, are produced. We studied the attraction of P. persimilis to the volatiles from spider mite-damaged gerbera leaves and how attraction is affected by starvation and previous experience. Phytoseiulus persimilis that were reared on spider mites (T. urticae) on Lima bean were not attracted to spider mite-induced volatiles from gerbera. Starvation did not influence the predator's response to these volatiles. In contrast, predators that were reared on spider mites on gerbera leaves were strongly attracted to volatiles from spider mite-infested gerbera. This was found also for predators that originated from a culture on spider mite-infested bean and were offered six days of experience with spider mites on gerbera leaves.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 52
    ISSN: 1573-0832
    Schlagwort(e): antagonism ; biological control ; modified dual plate culture method (MDPCM) ; Pythium acanthicum ; P. oligandrum ; P. periplocum ; P. ultimum var. ultimum ; sclerotia bait technique
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Mycoparasitic Pythium species with spiny oogonia were surveyed in 50 Palestinian agricultural fields subject to different cropping practices using the Sclerotia Bait Technique (SBT) and the Surface-Soil-Dilution-Plate method (SSDP) with the selective VP3 medium. The mycoparasitic Pythium species were obtained from 21 (42%) soils using the SSDP method and from 37 (74%) soils using SBT. Pythium acanthicum and P. oligandrum were isolated by both methods, whereas P. periplocum was isolated only by the SBT. Using a newly modified dual plate culture method (MDPCM), the three mycoparasites showed varying antagonistic performance against several Pythium host species under a range of in vitro conditions. However, P. periplocum and P. oligandrum were found to be active biocontrol agents against P. ultimum, the damping-off organism of cucumber. This pathogen was antagonized, on thin films of water agar, by the three mycoparasites, and was moderately susceptible to P. periplocum while slightly susceptible to P. acanthicum and P. oligandrum. In direct application method in which antagonistic mycoparasites were incorporated into peat/sand mixture artificially infested with P. ultimum under growthroom conditions, Pythium oligandrum and P. periplocum (at 500 CFUg−1) significantly improved seedling emergence and protected seedlings from damping-off. In the seed coating method, biocontrol by two types of seed dressing (homogenate- or oospore coated seeds), was comparable to that achieved by direct application.
    Materialart: Digitale Medien
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  • 53
    Digitale Medien
    Digitale Medien
    Springer
    Experimental and applied acarology 23 (1999), S. 281-296 
    ISSN: 1572-9702
    Schlagwort(e): bodyguards ; plant–predator mutualism ; tritophic interactions ; castor bean ; phytoseiids ; life history ; pollen ; banker plant ; biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The phytoseiid mite Iphiseius degenerans (Berlese) is an effective predator of western flower thrips, Frankliniella occidentalis (Pergande), in Dutch greenhouses. In the Mediterranean area, castor bean, Ricinus communis L., is known as a year-round host plant for this predatory mite. On flowering castor bean plants in greenhouses, I. degenerans can be found in densities of more than 100 per leaf. For this reason, the plant is being used as a ‘banker’ plant to augment biological control. It has been shown that pollen produced by the large apical flowers sustains reproduction and development for these mites. The objective of this study was to measure the contribution of the extrafloral nectar of this plant to the reproductive success of this predatory mite. A study conducted at 25°C in presence of free water showed that (1) I. degenerans is unable to develop beyond the protonymphal stage when fed only nectar and leaf tissue, (2) its ovipositional rate is higher when pollen is supplemented with nectar, (3) its reproduction ceases within a few days when fed on nectar only, but the predator can survive for several weeks and resume oviposition when fed pollen again and (4) the feeding of young females for one or two weeks with nectar only extends their longevity by approximately the same period and only slightly diminishes their lifetime reproductive potential (R0), as compared to mites continuously fed pollen. It can be concluded that extrafloral nectar can provide an important contribution to population growth and maintenance of I. degenerans on R. communis, particularly in pre- and post-blooming periods. Assuming these predators are beneficial to the plant in clearing them of herbivorous mites and thrips, this relationship may be regarded as an example of plant–predator mutualism. The combination of pollen and extrafloral nectar makes castor bean an ideal rearing and banker plant for I. degenerans.
    Materialart: Digitale Medien
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  • 54
    Digitale Medien
    Digitale Medien
    Springer
    Experimental and applied acarology 23 (1999), S. 741-763 
    ISSN: 1572-9702
    Schlagwort(e): biological control ; interspecific competition ; leaf hairiness ; grapevine ; Tetranychidae ; Eriophyidae ; Phytoseiidae ; Stigmaeidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In a three-year study, mite populations were monitored in two vineyards, each having two grape varieties with different leaf hair density. In both vineyards native phytoseiids were present: Amblyseius andersoni in one vineyard, and Phytoseius finitimus in the other. The economically important predators Kampimodromus aberrans and Typhlodromus pyri were released in both vineyards in order to study their efficacy in controlling tetranychids and eriophyids and their persistence during periods of prey scarcity. In both vineyards, relative abundances of the mite species, especially phytoseiids, were found to differ on different varieties in the same vineyard. In the first experiment, A. andersoni reached higher densities and was more persistent on the variety with slightly pubescent leaf under-surface (Merlot). Typhlodromus pyri and K. aberrans releases were successful and the mites became more abundant on the variety with pubescent leaf under-surface (Verduzzo). In the second experiment, P. finitimus was more abundant on a variety with pubescent leaf under-surface (Prosecco) than with glabrous leaf under-surface (Riesling). The most interesting results of the present study concerned the interactions between native and released predators. In the first vineyard, different results were obtained when releasing T. pyri on the two varieties. On the variety with pubescent leaves, A. andersoni was rapidly displaced by T. pyri, whereas the former species persisted on the other variety throughout the three-year study, apparently becoming dominant during the last season. In contrast to T. pyri, interactions between K. aberrans and A. andersoni in this vineyard did not depend on variety. The results of the experiments carried out in the second vineyard stressed the importance of interspecific competition for phytoseiid releases. Typhlodromus pyri colonization failed on both varieties. Kampimodromus aberrans releases appeared to be more successful on Riesling than on Prosecco, where P. finitimus was more abundant. At the end of the experiments, K. aberrans displaced P. finitimus on both varieties.
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  • 55
    ISSN: 1572-9702
    Schlagwort(e): Citrus ; biological control ; Phytoseiidae ; Stigmaeidae ; pesticide disruption ; Thysanoptera
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A series of experiments was initiated on ‘Tahiti’ lime trees to assess possible involvement in yield reduction by one or more species of thrips, especially Frankliniella bispinosa (Morgan) and F. kelliae Sakimura (Thysanoptera: Thripidae). Different pesticides were applied to ensure adequate coverage on flowers and to maintain effective thrips control. Outbreaks of spider mites were anticipated because of the pesticides used and frequency of application. Therefore, population dynamics of the citrus red mite, Panonychus citri (McGregor) (Acari: Tetranychidae) and the predacious mites Typhlodromalus peregrinus (Muma) (Acari: Phytoseiidae) and Agistemus floridanus Gonzalez (Acari: Stigmaeidae) were monitored in four pesticide treatment regimes during flowering on ‘Tahiti’ lime, Citrus latifolia Tanaka in south Florida. Yield was significantly reduced in four pesticide treatment regimes by 41, 31, 28 and 17% relative to the untreated control. Elimination of predacious mites by the selected pesticides resulted in higher sustained populations of P. citri on treated trees compared to those untreated. The pesticide regimes resulted in differences in population densities of both citrus red mite and its key predators. Depending upon the treatment regime and application date(s), the duration and magnitude of disruption resulted in significant differences in yield. P. citri densities that averaged 5.2 or more per leaf during January–February, or 4.3 or more per leaf during January–March, or 3.9 or more per leaf during January– April contributed substantially to the feeding injury and resulted in reduced yield. Typhlodromalus peregrinus was the most common predacious mite collected during this study (80.4%) followed by A. floridanus with 15.7%. This study demonstrated that the use of one or more pesticides on ‘Tahiti’ lime trees can negatively impact populations of citrus red mites and their associated predators to the detriment of yield. The magnitude of impact was dependent upon the treatment regime and application date(s). Spider mites increased because of reduced predator populations and use of these pesticides, especially in combination, is to be discouraged.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 56
    ISSN: 1572-9702
    Schlagwort(e): Phytoseiidae ; walking speed ; biological control ; tritrophic interactions ; Gerbera jamesonii ; trichomes.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The effect of leaf hairs on searching efficiency of adult female Phytoseiulus persimilis was investigated. For this purpose we used the ornamental crop Gerbera jamesonii and determined the predator's searching efficiency on three cultivars that differ largely in the density of leaf hairs on the undersurface of the leaves. Walking speed of the mites was highest on the cultivar with the lowest leaf hair density. Walking activity, defined as the percentage of time spent walking, was not dependent on leaf hair density of the cultivars. At both prey densities tested, time until first predation increased with leaf hair density. The predation rate of adult female P. persimilis is affected by trichome density, particularly when prey density is low. At prey densities of 1.3 and 2.5 Tetranychus urticae eggs cm–2, predation rate was inversely related to leaf hair density. At a prey density of 8.0 eggs cm–2 no significant effect of leaf hair density on predation rate was found. These negative effects on searching efficiency and predation success at low prey density of P. persimilis suggest that biological control of T. urticae on gerbera may be hampered by leaf hairs. © Rapid Science Ltd. 1998
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  • 57
    ISSN: 1572-9702
    Schlagwort(e): release ; establishment ; Amblyseius fallacis ; biological control ; Panonychus ulmi
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract We introduced a mass-reared pyrethroid-resistant strain of the predatory phytoseiid mite Amblyseius fallacis (Garman) into an Ontario peach orchard in an attempt to control populations of the phytophagous mites Panonychus ulmi Koch and Tetranychus urticae Koch (Acari: Tetranychidae). Releases of 1,000 and 2,000 mites per tree were made, at three different times. The release of 2,000 mites per tree in June and in July resulted in significantly higher phytoseiid densities than was observed on control trees. However, densities of P. ulmi or T. urticae were not significantly affected by any release rate or by timing. The release of 1,000 A. fallacis per tree, or of any density in August, did not significantly increase phytoseiid abundance. In the following year, population dynamics of both phytoseiid and phytophagous mites were not significantly affected by the previous year's release. Amblyseius fallacis can be a useful predator in some fruit orchards. However, further research is necessary into the timing and rate of release, modified spray programmes, and with different crops, in order to clarify the role of this species for biological control in Ontario peach orchards.
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  • 58
    Digitale Medien
    Digitale Medien
    Springer
    Experimental and applied acarology 23 (1999), S. 97-118 
    ISSN: 1572-9702
    Schlagwort(e): Chilocorus ; Coccinellidae ; Exochomus ; Hemisarcoptes ; ultrastructure ; phoresy ; biological control ; parasitism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The non-phoretic stages of mites of the genus Hemisarcoptes are predators of the family Diaspididae. The heteromorphic deutonymph (hypopus) maintains a stenoxenic relationship with beetles of the genus Chilocorus. The mites attach to the subelytral surface of the beetle elytron during transport. There is variation in mite density among species of Chilocorus. Both Hemisarcoptes and Chilocorus have been applied to biological control programmes around the world. The objective of this study was to determine whether subelytral ultrastructure (spine density) plays a role in the evolution of symbiosis between the mite and the beetle. The subelytral surfaces of 19 species of Chilocorus and 16 species of Exochomus were examined. Spine density was determined for five subelytral zones: the anterior pronotal margin, medial central region, caudoventral tip, lateral distal margin and epipleural region. Spine density on the subelytral surface of Chilocorus and Exochomus was inversely correlated with the size of the elytron for all zones except the caudoventral tip. This suggests that an increase in body size resulted in a redistribution of spines and not an addition of spines. The pattern of spine density in Exochomus and Chilocorus follows a single size–density trajectory. The pattern of subelytral ultrastructure is not strictly consistent with either beetle phylogeny or beetle allometry. The absence of spines is not correlated with either beetle genus or size and species of either Chilocorus or Exochomus may be devoid of spines in any zone, irrespective of body size. A general difference between species of Chilocorus and Exochomus is the fact that while spine density in Chilocorus is clinal relative to the size gradient, Exochomus is dichotomous and likely to have either many spines or no spines in a particular zone. No species of Chilocorus was completely devoid of spines. Five species of Exochomus had no spines at all, thus making it difficult to interpret the primary function of the subelytral spines in a general way. Within the genus Chilocorus, spine density may play a synergistic role in host association. Based on morphological evidence alone, these findings lead to the hypothesis that the species of Chilocorus that would be most conducive to biological control application in conjunction with Hemisarcoptes would be Chilocorus cacti, Chilocorus distigma, Chilocorus fraternus, Chilocorus orbus, Chilocorus tristis and, to a lesser extent, Chilocorus bipustulatus. © Rapid Science Ltd. 1998
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  • 59
    ISSN: 1572-9702
    Schlagwort(e): biological control ; strawberry ; Tetranychus urticae ; Amblyseius californicus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Naturally occurring beneficials, such as the phytoseiid mite Amblyseius californicus McGregor and the insects Stethorus punctillum Weise, Conwentzia psociformis (Curtis) and others, controlled Tetranychus urticae Koch in 11 strawberry plots near Valencia, Spain, during 1989–1992. The population levels of spider mites in 17 subplots under biological control were low or moderate, usually below 3000 mite days and similar to seven subplots with chemical control. In most of the crops A. californicus was the main predator, acting either alone or together with other beneficials. Predaceous insects colonized the crop when tetranychids reached medium to high levels. For levels above one spider mite per leaflet, a ratio of one A. californicus per five to ten T. urticae resulted in a decline of the prey population in the following sample (1–2 weeks later). These results suggest that naturally occurring predators are able to control spider mites and maintain them below damaging levels in strawberry crops from the Valencia area.
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  • 60
    ISSN: 1573-5117
    Schlagwort(e): Myriophyllum aquaticum ; Lysathia n. sp. ; Chrysomelidae ; biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The plant, Myriophyllum aquaticum (Vell.) Verdc. (parrot's feather), is one of five alien water weeds causing problems in South Africa. M. aquaticum is presently considered a minor weed problem, but it is expected that it will become more important as the more troublesome water weeds are brought under control. For this reason, research was initiated on the possibility of biological control of M. aquaticum. Exploratory surveys on M. aquaticum in South America, the continent of origin, yielded several promising insect natural enemies. A leaf-feeding beetle, Lysathia n. sp. (Chrysomelidae), was the first biological control candidate imported. Its biology was studied and under quarantine conditions it was found that Lysathia n. sp. was host-specific, feeding and reproducing only on M. aquaticum. Permission for release was sought and given by the National Department of Agriculture, Directorate of Plant and Quality Control. This insect was released at five sites throughout the country in December 1995. Post-release studies on this beetle have been in progress for three years. An account follows of its field performance at one of these sites: Culmpine, Vaalwater, Northern Province on the Mokolo River. The results obtained at the Culmpine site indicate that Lysathia n. sp. shows promise as a biological control agent. A second agent may however be required at a later stage.
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  • 61
    ISSN: 1573-5117
    Schlagwort(e): actinomycetes ; biological control ; bluegreen algae ; cyanobacteria ; protozoa ; Streptomyces
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A range of naturally occurring organisms are available for the biological control of cyanobacteria: including viruses, bacteria, fungi, actinomycetes and protozoa. Development of these organisms as biological control agents involves isolation from environmental samples, characterisation of anti-cyanobacterial activity, microcosm and large-scale field experiments and final development of a biological control lake management strategy. Two groups of antagonist are considered in detail – actinomycetes (e.g. Streptomyces exfoliatus, mode of action by production of a lytic agent) and protozoa (Nuclearia delicatula and Nassula tumida, mode of action by predation). The effectiveness of biological control agents in the lake environment depends on a range of biological and physico-chemical factors. Various strategies can be implemented to optimise their activity.
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  • 62
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 415 (1999), S. 265-269 
    ISSN: 1573-5117
    Schlagwort(e): grass carp ; submerged weeds ; biological control ; channels ; stocking rate
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Two experiments were conducted in Río Negro province (Argentina) to study macrophyte response to different stocking rates of the grass carp (Ctenopharyngodon idella Val.). The first of these was performed in nine polyethylene-lined ponds, 12 m2 each, planted with Illinois pondweed (Potamogeton illinoensis Morong) at two fish stocking rates, 100 and 360 kg ha-1. The second experiment was set up under natural conditions in a channel full of Potamogeton pectinatusL., Myriophyllum aquaticum (Vell.) Verd. and Chara contrariaA. Braun ex Kurtz, at 100 and 200 kg ha-1. In both cases, the initial individual fish weight was between 22 and 40 g. A complete randomised block design was used in both experiments. Five samples of plant biomass were taken per experimental unit. Data were subjected to ANOVA and LSD was used as a comparative test. In both cases, the experimental period was 2 months because of the herbivory under the high stocking rate completely depleted both the leaves of P. illinoensis under pond conditions and the aboveground plant biomass in the channel. The results showed a high potential of biocontrol under tested conditions and suggest a stocking rate lower than 100 kg ha-1 as enough for local conditions and for a prolonged fish presence in the area.
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  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 415 (1999), S. 203-206 
    ISSN: 1573-5117
    Schlagwort(e): Red water fern ; biological control ; mechanical control ; herbicide control ; utilization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Azolla filiculoides Lamarck (Pteridophyta: Azollaceae) (red water fern) is native to South America and was first recorded in South Africa in 1948. The lack of natural enemies and the presence of enriched waters have contributed to its establishment throughout the country where dense infestations cause severe degradation of aquatic ecosystems and limit their utilisation. The biology of A. filiculoides precludes it from being controlled manually or mechanically and herbicidal control in the aquatic environment is undesirable. Biological control is suggested as the only sustainable control method for this weed and a natural enemy, Stenopelmus rufinasus Gyllenhal (Coleptera: Curculionidae), was released for this purpose in late 1997. The weevil has established well and has caused a significant decline in the Azolla mat at a number of sites, suggesting that the weevil will be an efficient tool in the management of A. filiculoides in South Africa.
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  • 64
    Digitale Medien
    Digitale Medien
    Springer
    World journal of microbiology and biotechnology 15 (1999), S. 535-543 
    ISSN: 1573-0972
    Schlagwort(e): Biochemical ; biological control ; molecular ; rhizobacteria
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Werkstoffwissenschaften, Fertigungsverfahren, Fertigung
    Notizen: Abstract The rhizosphere is the narrow zone of soil surrounding the root that is subject to influence by the root. Rhizobacteria are plant-associated bacteria that are able to colonize and persist on roots. An understanding of the ecology of a microorganism is a fundamental requirement for the introduction of a microbial inoculant into the open environment. This is particularly true for biological control of root pathogens in the rhizosphere, where one is actively seeking to alter the ecological balance so as to favour growth of the host plant and to curtail the development of pathogens. Some strains of plant growth-promoting rhizobacteria can effectively colonize plant roots and protect plants from diseases caused by a variety of root pathogens and growth promotion of plants through direct stimulation of growth hormone. Such beneficial or plant health-promoting strains are emerging as promising biocontrol agents. They are suitable as soil inoculants either individually or in combination and may be compatible with current chemical pesticides. Considerable progress has been achieved using molecular genetic techniques to elucidate the important microbial factors or genetic traits involved in the suppression of fungal root diseases. Strategies utilizing molecular genetic techniques have been developed to complement the ongoing research ranging from the characterization and genetic improvement of a selected biocontrol agent to the measurement of its persistence and dispersal. Finally, biocontrol is considered as part of a disease control strategy like integrated pest management which offers a successful approach for the deployment of both agro-chemicals and biocontrol agents.
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  • 65
    ISSN: 1573-8469
    Schlagwort(e): Alternaria brassicae ; biological control ; cross infection ; disease management
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Resistance in susceptible mustard cv. PR-15 against the highly virulent A. brassicae isolate A (AbA) and moderately virulent isolate C (AbC) was induced using an avirulent Alternaria brassicae isolate D (AbD). The induction of resistance due to AbD against AbA or AbC resulted in significant reduction in disease severity. The A. alternata (Aa) failed to induce resistance against AbA and AbC, on the contrary it induced susceptibility against them.
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  • 66
    Digitale Medien
    Digitale Medien
    Springer
    European journal of plant pathology 105 (1999), S. 177-189 
    ISSN: 1573-8469
    Schlagwort(e): biological control ; grey mould ; mechanisms ; pathogenicity enzymes ; proteolysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The role of protease of Trichoderma harzianum in the biocontrol of Botrytis cinerea was examined. Two isolates of T. harzianum were compared for their ability to produce protease in liquid culture medium and on the surface of bean leaves. The biocontrol agent T. harziaum T39 produced 58 mU/ml of protease and T. harzianum NCIM1185 produced 54 mU/ml on the 5th day of growth in liquid culture medium. On bean leaves, combinations of B. cinerea and T. harzianum isolates were examined for the synthesis of protease. The protease activities were 0.9 and 0.6 mU/ml for T. harzianum T39 and NCIM1185, respectively, and 0.5 mU/ml for B. cinerea alone after 48 h of incubation. In the presence of T. harzianum T39 culture liquid containing protease, a 55% reduction in B. cinerea germination and a 80% reduction in the germ tube length were observed after 17 h of incubation in vitro. When T. harzianum isolates were added to B. cinerea on bean leaves, increased synthesis of protease was observed (1.0 and 1.2 mU/ml for T39 and NCIM1185, respectively). In the presence of T. harzianum NCIM1185 protease, although the rate of germination was reduced, B. cinerea attained 98% germination after 17 h of incubation. The hydrolytic enzymes produced by B. cinerea, endo-polygalacturonase (PG) and exoPG were partially deactivated by protease from the T. harzianum isolates. Carboxymethyl cellulase was deactivated only by protease of NCIM1185. On the surface of bean leaves, the protease (obtained from liquid culture medium of T. harzianum isolates) resulted in 56–100% reduction of disease severity. The culture liquid containing protease synthesized on the surface of bean leaves treated with B. cinerea and with T. harzianum was collected and added to fresh leaves infected by B. cinerea. There was 56–100% and 30–75% reduction of disease severity with liquid droplet collected from the leaves treated with T. harzianum T39 and NCIM1185, respectively. Increased control of disease was obtained by combining the conidia of T. harzianum isolates with protease obtained from culture media. Protease inhibitors, trans-epoxysuccinyl-L-leucylamido-(4-guanidino)butane (E64), antipain hydrochloride, and a mixture of inhibitors, but not pepstatin A, fully or partially nullified the biocontrol effect of T39. T39 was found to be a poor producer of chitinase and β-1,3-glucanase in vitro. These enzymes were not detected on leaves treated with T39. Involvement of protease in biocontrol of B. cinerea is suggested.
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  • 67
    ISSN: 1573-8248
    Schlagwort(e): Acari ; biological control ; generalist ; intraspecific predation ; multiple species release ; predatory mites ; specialist
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract We examined intra- and interspecific predation of adult females and immature stages of the generalist Neoseiulus californicus and the specialist Phytoseiulus persimilis. Adult females and immatures of both predators exhibited higher predation rates on larvae than on eggs and protonymphs. N. californicus fed more inter- than intraspecifically. Predation on P. persimilis by N. californicus was more severe than vice versa. P. persimilis had higher predation rates on conspecifics than heterospecifics and was more prone to cannibalism than N. californicus. When provided with phytoseiid prey, P. persimilis suffered higher mortality than N. californicus. When held without food, adult females and protonymphs of N. californicus survived longer than the corresponding stages of P. persimilis. N. californicus females were able to sustain oviposition when preying upon P. persimilis, whereas cannibalizing females did not lay eggs. Females of P. persimilis were not able to sustain oviposition, irrespective of con- or heterospecific prey. Immatures of both predators were able to reach adulthood when provided with either con- or heterospecifics. Juvenile development of N. californicus was shorter with heterospecific vs. conspecific larvae; mortality of P. persimilis immatures was less when feeding on conspecific vs. heterospecific larvae. Different behavioral pattern in intra- and interspecific predation are discussed in regard to their feeding types (generalist vs. specialist).
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  • 68
    ISSN: 1573-8248
    Schlagwort(e): biological control ; Botrytis aclada ; Botrytis cinerea ; cyclamen ; ecological adaptation ; hydrangea ; lily ; onion ; temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Ulocladium atrum and Gliocladium roseum are fungal antagonists capable of suppressing sporulation of Botrytis spp. on dead plant parts. The effect of temperature (3 to 36 °C) on antagonist conidial germination and mycelial growth was assessed on agar. In addition conidial germination of U. atrum was measured on dead lily leaves. The optimum temperature of both antagonists for both conidial germination and mycelial growth was between 27 and 30 °C. U. atrum was less affected by lower temperatures than G. roseum. At optimum temperature, 50% of conidia of U. atrum and G. roseum germinated within 2.6 and 10.0 hrs, respectively. At low sub-optimal temperatures (6 °C), 50% of conidia germinated within 18 and 96 hours, respectively. In bioassays on dead onion leaves, U. atrum suppressed sporulation of B. cinerea and B. aclada at all temperatures tested (6 to 24 °C) by more than 85%. On dead cyclamen leaves, G. roseum was more efficient than U. atrum at 21 and 24 °C but, in contrast to U. atrum, showed no antagonistic activity at temperatures below 21 °C. On dead hydrangea leaves, U. atrum significantly reduced sporulation of B. cinerea at temperatures as low as 3 and 1 °C. Under Dutch growing conditions, the mean air temperature during leaf wetness periods in onion and lily fields was 15 °C with temperatures only occasionally above 20 °C. In greenhouse crops of cyclamen, the mean temperature during high humidity periods was 17 °C. It is therefore concluded that U. atrum is better adapted than G. roseum to temperatures which occur in the field, in greenhouse crops such as cyclamen, or during cold storage of plant stocks.
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  • 69
    ISSN: 1573-8248
    Schlagwort(e): Anaxipha longipennis ; biological control ; Gryllidae ; Metioche vitatticollis ; parasitism ; predation ; Trichogramma
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Egg mortality of rice leaf folders Cnaphalocrocis medinalisand Marasmia patnalis was studied in unsprayed irrigated rice fields in Laguna Province, the Philippines. Mortality was assessed by field exposure of laboratory-laid eggs for two days and by monitoring of field-laid eggs. Egg disappearance, the major mortality factor, was low in the first four weeks after transplanting and then increased. Egg parasitism by Trichogrammajaponicum was highest at the start of the crop and decreased to a low level towards crop maturity. Non-hatching of eggs was of minor importance. Over the total duration of the egg stage, the average disappearance of exposed laboratory-laid eggs was40%, and of field-laid eggs 46%. Egg mortality due to parasitism averaged 15% and 18%, respectively. The potential impact of egg parasitism is probably partly obscured by the disappearance of parasitized eggs. Mortality rates were highly variable between egg cohorts, but with multiple regression analysis several factors were identified that statistically explained a significant part of this variation. The results suggest that the predatory crickets Metiochevittaticollis and Anaxipha longipennis play a major role in egg disappearance, and that egg parasitism is positively dependent on the overall density of host eggs of Trichogramma in the field.
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  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Biologia plantarum 42 (1999), S. 567-573 
    ISSN: 1573-8264
    Schlagwort(e): H+-ATPase ; phytohormones ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The potassium uptake by potato tuber discs tissues freshly cut and after 24 h of ageing in the presence or not of abscisic acid was investigated. Uptake kinetics revealed a biphasic dependence on external K+ concentrations. At concentration less than 10 mM, uptake was mediated by a saturable component and a linear component became apparent at higher concentrations. At low K+ concentrations (lmM), the capacity of K+ uptake diminished by 2 times after ageing. Treatment of tissues with ABA increased the rate of K+ uptake. In both fresh and aged tissues the uptake was strongly enhanced by fusicoccin and decreased by several metabolic inhibitors and ATPase inhibitors, underlying the active nature of uptake and suggesting the involvement of a plasmalemma H+-ATPase in K+ transport system.
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  • 71
    Digitale Medien
    Digitale Medien
    Springer
    BioControl 44 (1999), S. 159-169 
    ISSN: 1573-8248
    Schlagwort(e): biological control ; Euphorinae ; species identification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Four parasitoids of the subfamily Euphorinae are common in New Zealand pasture. These are Microctonus aethiopoides, M. hyperodae, M. zealandicus and Dinocampus coccinellae. There is overlap in these parasitoids' host ranges and, although adults of these species can be identified morphologically, their larval stages have not yet been compared. This contribution provides morphological descriptions of the head capsules of 1st instar larvae that enable the four parasitoid species to be distinguished. Diagnostic characteristics are the shape of the mandible and the pattern of sclerotisation on the hypopharynx. Post 1st instar larvae can be identified by retrieving the shed 1st instar head capsule from the host abdomen.
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  • 72
    Digitale Medien
    Digitale Medien
    Springer
    BioControl 44 (1999), S. 347-367 
    ISSN: 1573-8248
    Schlagwort(e): Aphidiidae ; biological control ; Chrysopidae ; Coccinellidae ; entomopathogens ; Hemerobiidae ; Syrphidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Sixteen cohorts of the brown citrus aphid, Toxoptera citricida, were followed from colony initiation to maturation/extinction in citrus groves at two sites in Puerto Rico and nine sites in Florida, USA. Infested citrus terminals were sampled repeatedly in a non-destructive manner and data recorded on the recruitment of natural enemies and the fate of aphid colonies. Coccinellidae were the most efficient predators of T. citricida, primarily Cycloneda sanguinea, and Coelophora inaequalis (Puerto Rico), C. sanguinea, Harmonia axyridis (Florida). Coccinellids were abundant in citrus year-round in Puerto Rico, but in Florida citrus their abundance peaked in spring and declined thereafter. Syrphid flies were other important predators, especially Pseudodorus clavatus (Florida and Puerto Rico) and Ocyptamus fuscipennis (Puerto Rico). Syrphids increased in abundance from spring to fall in both regions. Other predators included Cereaochrysa lineaticornis, Chrysoperla rufilabris (Chrysopidae) and Micromus posticus (Hemerobiidae). The parasitoid Lysiphlebus testaceipes was ubiquitous in T. citricida cohorts, but its impact on colony survival was usually low. The fungal pathogen Verticillium lecanii was a significant source of colony mortality at one site in Puerto Rico, but was not observed on T. citricida in Florida.
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  • 73
    Digitale Medien
    Digitale Medien
    Springer
    BioControl 44 (1999), S. 291-299 
    ISSN: 1573-8248
    Schlagwort(e): biological control ; cerambycid ; Coleoptera ; pine wood borer ; poplar wood borer
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Artificial diets for the colydiid beetle, Dastarcus helophoroides, a predator of cerambycid beetles and xylocopid bees, were evaluated. Hatched larvae were reared on artificial diets composed of silkworm pupa-powder, dry yeasts, yeast extract, sucrose, peptone, squid liver oil, preservatives and distilled water, but their emergence rate was very low. If larvae were fed paralyzed cerambycid larvae till they became approximately 8 mm in body length and then reared on artificial diet, emergence rates were high. Using the latter method, mass-production of this colydiid beetle is feasible.
    Materialart: Digitale Medien
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  • 74
    Digitale Medien
    Digitale Medien
    Springer
    BioControl 44 (1999), S. 475-487 
    ISSN: 1573-8248
    Schlagwort(e): bacterial antagonists ; biological control ; Pantoea agglomerans ; pseudosclerotia ; Sclerotiniaceae ; Vaccinium macrocarpon
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Bacteria inhibitory to Moniliniaoxycocci, the cranberry cotton ball pathogen, were identified. Eighty-three bacteria isolated from a cranberry marsh and Erwinia herbicola C9-1,which is being developed elsewhere for the biological control of fire blight of pome fruits, were tested fortheir ability to inhibit radial growth and conidial germination of M. oxycocci in vitro. IsolateBA35 from cranberry (tentatively identified as Pseudomonas syringae pv. morsprunorum) and E. herbicola C9-1 completely inhibited radial growth of M. oxycocci. BA35 and C9-1 were among the most effective of 21 bacteria tested for inhibition of conidial germination. Growth of bacteria in sclerotial extracts of M. oxycocci and Sclerotinia sclerotiorum was determined in order to select isolates that might be successful in degradingsclerotia, thereby reducing the viability of M.oxycocci. Populations of isolates 62 and S-18(identities unknown), and S-19 (tentatively identified as Micrococcus luteus), increased approximately3.0--5.0 log10 units in all extracts within 24 h. Populations of isolate S-10 increased by about 3.5log10 units in all sclerotial extracts within 48 h. Populations of isolate S-49 (identity unknown)were lower in extracts of M. oxycocci than S. sclerotiorum after 48-h. In buffer controls, bacterial populations remained stable or decreased over the 48-h period.
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  • 75
    Digitale Medien
    Digitale Medien
    Springer
    BioControl 43 (1999), S. 441-456 
    ISSN: 1573-8248
    Schlagwort(e): agroecosystems ; biological control ; Carabidae ; carabid community ; Coleoptera ; generalist predators ; natural enemy abundance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Generalist natural enemies such as carabid beetles have the potential to maintain a variety of pests below outbreak levels in annual crops. To assess the relationship between carabid beetle abundance and field rates of prey removal, we created plots surrounded by different boundaries that selectively affected dispersal of edaphic arthropods, primarily carabids. Three treatments were established: (1) naturally occurring communities, (2) augmented communities using ingress boundaries, and (3) reduced communities using egress boundaries. Selective boundaries altered carabid communities with minimal habitat alteration and without use of insecticides. Three times during the growing season, a fixed number of onion fly pupae were placed in plots to evaluate the impact of carabid abundance on predation rates. A combination of vertebrate and invertebrate exclosures allowed us to evaluate prey removal by invertebrates alone. In comparison to the no boundary treatment, carabids increased 54.2% and decreased 83.1% in plots surrounded by ingress and egress boundaries respectively. Predation rates were positively correlated with carabid abundance (r2 = 0.70, p 〈 0.0001). Significantly more pupae were removed from exclosures allowing access to invertebrates alone than from total exclosures, suggesting that invertebrates represented an important group of predators. Laboratory trials tested the feeding potential of the four most abundant carabid species and showed that they readily consumed onion fly pupae, supporting our hypothesis that carabids were the main predators in field tests. This study corroborates and extends previous observations of the importance of carabid beetles as generalist predators of insect pests in agricultural fields.
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  • 76
    ISSN: 1573-8248
    Schlagwort(e): Acari ; biological control ; cannibalism ; generalist ; interspecific predation ; multiple predators release ; predatory mites ; specialist
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Discrimination between and predation preference for con- or heterospecific larvae was examined for adult females of P. persimilis and N. californicus in plexiglass cages with and without their primary prey T. urticae. Rates of intra- and interspecific predation on larvae were measured for females held on leaves and provided with excess amounts of spider mites. Females of the generalist N. californicus distinguished con- and heterospecific larvae and preferred to prey upon the latter. Females of the specialist P. persimilis appeared to lack discrimination ability and fed equally on con- and heterospecifics. When spider mites and phytoseiids were offered simultaneously, all P. persimilis females chose to first attack T. urticae, whereas N. californicus females attacked both tetranychids and heterospecific phytoseiids. Females of both predators preyed upon phytoseiid larvae when held on leaves with surplus T. urticae: while P. persimilis fed on both con- and heterospecifics, N. californicus attacked larvae of P. persimilis but avoided cannibalizing larvae. The different behaviors of P. persimilis and N. californicus are discussed with regard to different predation types (generalists vs. specialists) and the possible consequences of mixed release for biological control of spider mites in greenhouses.
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  • 77
    ISSN: 1573-8248
    Schlagwort(e): biological control ; kaolin ; mycoherbicide ; preservation ; weed
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Different solid substrates were investigated as spore production methods for Stagonospora convolvulistrain LA39, a potential bioherbicide for field bindweed (Convolvulusarvensis L.). Up to 4 × 108 spores/g of substratewere yielded on cous-cous (cracked hard wheat). Thespores were as pathogenic as those grown on artificial medium (V-8-juice agar). The air-drying on kaolin and storage at 3 °C kept spores viable and pathogenic for 180 days. Spore germination exceeded70% for the first 140 days and then declined to 50%after 175 days. Less than 5% of spores were still viable after 17 months. The preservation of stock cultures in 10% glycerine at −80 ° C and in liquid nitrogen did not affect viability orpathogenicity of the spores.
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  • 78
    ISSN: 1573-8264
    Schlagwort(e): calmodulin ; H+-ATPase ; lanthanum ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Previous results with potato tuber discs showed that a treatment with abscisic acid stimulated K+ uptake. In this investigation, we determine the relationship between increased K' uptake and H+extrusion, and Ca2+ fluxes by treating tissues with specific Ca2+ channel blocker (La3+), calmodulin (CaM) inhibitors (chlorpromazine and W7), and with Ca2+ ionophore (A23187). K+ uptake increased with increasing external pH whether tissues were treated with ABA or not. Treatment of tissues with La3+ inhibited K+ uptake, whereas CaM inhibitors have no effect. By contrast ABA and A23187 produced a synergistic effect, suggesting that ABA may act in part, on K+ uptake, like a Ca2+ agonist, in accord with Huddart's hypothesis.
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  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 89 (1998), S. 289-295 
    ISSN: 1570-7458
    Schlagwort(e): Hymenoptera ; Trichogrammatidae ; Uscana lariophaga ; Coleoptera ; Bruchidae ; Callosobruchus maculatus ; cowpea ; storage pest ; biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In West Africa, Uscana lariophaga (Hymenoptera: Trichogrammatidae) parasitizes the eggs of Callosobruchus maculatus (Coleoptera: Bruchidae), an important pest of stored cowpea. The impact of the egg parasitoid on pest populations was evaluated in clay pots used in traditional storage in Niger. At the beginning of the storage period cowpeas were infested with different densities of larval instars and adults of C. maculatus and inoculated with one density of U. lariophaga. The higher the initial densities of C. maculatus, the better the egg parasitoid was able to establish itself and to control the population of C. maculatus, limiting the damage to cowpea. After three months of storage, the egg parasitoid significantly reduced the number of C. maculatus adults by 68 at the lowest and 86 percent at the highest initial density of the beetle; the percentage of damaged beans was reduced by 13 and 19% respectively.
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  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 86 (1998), S. 1-11 
    ISSN: 1570-7458
    Schlagwort(e): Heterorhabditidae ; Steinernematidae ; Heterorhabditis bacteriophora ; Steinernema carpocapsae ; Steinernema feltiae ; entomopathogenic nematodes ; turfgrass ; Japanese beetle ; Popillia japonica ; population dynamics ; spatial distribution ; edaphic factors ; biological control ; colonization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Entomopathogenic nematodes (Rhabdita: Heterorhabditidae and Steinernematidae) have been effective as inundative biological control agents of scarab larvae (Coleoptera: Scarabaeidae) in turfgrass. Entomopathogenic nematodes also occur naturally in turfgrass and endemic or inoculated populations may be able to provide effective long-term control. Variation in Heterorhabditis bacteriophora and Steinernema carpocapsae spatial and temporal distribution along transects placed at different turfgrass sites in central New Jersey, USA, was investigated. H. bacteriophora tended to be recovered from fewer sections in a transect than S. carpocapsae, but the two species, overall, did not differ in patchiness of distribution. In one transect with a H. bacteriophora population S. feltiae was also recovered, but the two populations seldom overlapped spatially. In transects with adequate scarab larvae density for analysis, H. bacteriophora density and Popillia japonica larvae density were inversely correlated. This suggests that endemic H. bacteriophora populations may suppress P. japonica populations. In one transect, an epizootic of H. bacteriophora in an undetermined host may have occurred. Edaphic factors were relatively uniform along transects and were, at most, weakly correlated with nematode recovery. Uniform inoculative releases of H. bacteriophora tended to return to patterns of distribution typical of endemic populations.
    Materialart: Digitale Medien
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  • 81
    ISSN: 1570-7458
    Schlagwort(e): Acari ; Phytoseiidae ; biological control ; infochemicals ; disease ; transmission
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Adult females of the predatory mite Phytoseiulus persimilis Athias-Henriot are strongly attracted to infochemicals released by plants infested with their prey, the two-spotted spider mite (Tetranychus urticae Koch), thereby effectively locating their prey. However, we found a consistently lower degree of attraction to these infochemicals for a population of P. persimilis, which is called non-responding population. Here we demonstrate that this low degree of attraction is a contagious phenomenon and that it cannot be explained by differences in abiotic conditions, physiological state and experience of predators or by genetic differences between predator populations. Female predators exposed to dead conspecifics of the non-responding population and their products showed a lower degree of attraction to plant odours and a higher mortality than predators exposed to products of a living conspecific of the non-responding population. This was true 6–7 days after contact with dead conspecifics and their products whereas 2 days after contact no effects were detected. The present results are discussed in view of our hypothesis that the change in foraging behaviour as well as the high mortality rate are symptoms of a contagious disease affecting the non-responding population.
    Materialart: Digitale Medien
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  • 82
    ISSN: 1570-7458
    Schlagwort(e): tritrophic interactions ; solanaceae ; parasitoids ; biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 89 (1998), S. 47-55 
    ISSN: 1570-7458
    Schlagwort(e): Chrysoperla carnea ; Coccinella septempunctata ; Coleomegilla maculata ; Harmonia axyridis ; Ostrinia nubilalis ; Acyrthosiphon pisum ; prey suitability ; biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In a laboratory study two coccinellid species, Coleomegilla maculata (DeGeer) and Harmonia axyridis Pallas, completed preimaginal development on lacewing eggs, Chrysoperla carnea Stephens or pea aphids, Acyrthosiphon pisum (Harris) in similar times. Preimaginal survival on C. carnea eggs was similar to survival on A. pisum for all stages of C. maculata and H. axyridis. Coccinellid adults that developed on C. carnea eggs were smaller than adults reared on A. pisum. Coccinella septempunctata L. did not complete preimaginal development on C. carnea eggs. Chrysoperla carnea preimaginal developmental time was approximately 20 days when fed either C. maculata eggs or A. pisum. Chrysoperla carnea fed C. maculata eggs developed into smaller adults, compared to adults reared as larvae on A. pisum, Ostrinia nubilalis (Hübner) eggs, or A. pisum alternated daily with O. nubilalis eggs. C. carnea did not complete preimaginal development on H. axyridis eggs. Cannibalism occurred more frequently between C. carnea third instars than between C. maculata fourth instars. When a C. carnea third instar was paired with a C. maculata fourth instar, more C. maculata were preyed upon by C. carnea, regardless of the herbivorous prey density. In the field these two predator species may negatively affect each other and reduce their suppression of pest densities.
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  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 89 (1998), S. 103-109 
    ISSN: 1570-7458
    Schlagwort(e): Insecta ; supercooling capacity ; cold tolerance ; Hippodamia convergens ; Fusarium avenaceum ; Fusarium acuminatum ; pleomorphism ; biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The supercooling point (SCP) of an insect model, the lady beetle Hippodamia convergens Guérin-Menéville (Coleoptera, Coccinellidae) was markedly elevated by treatment with aqueous suspensions of the filamentous, ice nucleation active (INA) fungi Fusarium avenaceum and slightly elevated by Fusarium acuminatum. Addition of the surfactant Tween 80 to the fungal suspensions further reduced the supercooling capacity of adult beetles. When used alone the surfactant Triton X-100 produced a greater SCP elevation than Tween 20 or Tween 80. The emulsifier gum arabic was ineffective in elevating beetle SCPs when applied alone and when added to INA fungal preparations it decreased their efficacy. Aqueous suspensions of both viable sporulating and viable pleomorphic (a permanent, degenerative, nonsporulating cultural state) forms of both fungal species were more effective in elevating the SCP than killed preparations except for the pleomorphic F. acuminatum suspension in which the killed form was slightly more active. Application of INA fungi applied in combination with surfactants may be useful in the development of methods for the biological control of overwintering freeze-susceptible insect pests by decreasing their capacity to avoid lethal freezing by supercooling.
    Materialart: Digitale Medien
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  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 87 (1998), S. 103-108 
    ISSN: 1570-7458
    Schlagwort(e): predator foraging ; biological control ; Chrysoperla plorabunda ; Diuraphis noxia ; Rhopalosiphum padi
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Previous field experiments indicated that the presence of the bird cherry-oat aphid, Rhopalosiphum padi (L.), on perennial grasses can decrease the effectiveness of predatory lacewings, Chrysoperla plorabunda (Fitch), in reducing populations of the Russian wheat aphid, Diuraphis noxia (Mordvilko). We tested the hypothesis that R. padi deflects predation away from D. noxia because it feeds in sites that are more accessible to predators. We quantified the behavior of lacewing larvae on crested wheatgrass plants bearing either D. noxia alone or an equal mixture of D. noxia and R. padi. On non-flowering plants, R. padi typically occurred on leaf sheaths or open blades, and was encountered and captured more often than D. noxia, which usually fed within immature, rolled leaves. Overall time-budgets of lacewings did not differ between the pure-D. noxia and mixed-species treatments, but 〉75% of the time spent consuming aphids in the mixed-species treatment was devoted to R. padi. On flowering plants, D. noxia usually aggregated on the flag leaf below the inflorescence, whereas R. padi occurred mostly on leaf sheaths. Predators again captured R. padi more often than D. noxia, and spent more time consuming aphids in the mixed-species treatment than in the pure-D. noxia treatment. These behavioral observations support the hypothesis that non-target prey can hamper the short-term effectiveness of biological-control agents against D. noxia.
    Materialart: Digitale Medien
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  • 86
    ISSN: 1573-0832
    Schlagwort(e): Aquatic weeds ; biological control ; Cercospora pistiae ; fungal pathogens ; water cabbage
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Pistia stratioites , the water lettuce, is an important pantropical aquatic weed. It has been the target of successful classical biocontrol programmes utilizing an insect natural enemy collected in Brazil and introduced into Australia, Papua New Guinea and South Africa. Little attention was given to the fungal pathogens associated with this weed as potential biocontrol agents. An 11-month field survey in the state of Rio de Janeiro involving repeated visits to 12 sites, and a 2-month survey in the Amazonas Basin (Amazonas state) in Brazil, yielded only one pathogenic fungus on P. stratioites. This was identified as Cercospora pistiae. No previous record of this species has been made in Brazil nor in the New World. The fungus is described and its taxonomy and biocontrol potential discussed herein. C. pistiae is a damaging pathogen of water lettuce. Its distribution was restricted to two interconnected sites in Rio de Janeiro. A literature and herbaria survey yielded few fungi associated to water lettuce (8 species), probably reflecting a lack of adequate collection in the centre of origin of the plant.
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  • 87
    ISSN: 1573-0832
    Schlagwort(e): antagonism ; bacterization ; biological control ; cotton ; Pseudomonas fluorescens ; Pythium carolinianum ; root rot
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract A severe root rot disease of cotton caused by Pythium carolinianum was diagnosed in a cotton field in Beni-Musa village, 20 km southwest of El-Minia city, Egypt, during the summer of 1996. This was the first reported isolation of this fungus in Egypt. In the light of the importance of the cotton industry in Egypt, research was initiated to develop a biocontrol agent against Pythium carolinianum. In vitro agar plate technique identified a Pseudomonas fluorescens strain that was highly antagonist to Pythium carolinianum. Subsequent plant growth experiments establish that substantial disease control could be obtained by applying Pseudomonas fluorescens to the soil. Optimal control was obtained by mixing the bacteria with the soil rather than by dipping the cotton roots in the bacterial suspension immediately before planting. Disease was more severe in autoclaved soil than in nonsterile soil.
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  • 88
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 3 (1998), S. 111-116 
    ISSN: 1572-9745
    Schlagwort(e): stored product mites ; biological control ; history ; predators ; prey
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A history of the biological control of stored product mites is reviewed. Thirty-five references in the scientific literature were found principally dealing with acarine predators. The first paper to point out the specific value of Cheyletus eruditus as a predator of acaroid mites appeared in 1912. In 1965 biological control utilizing C. eruditus was put into practice for the first time and in 1986 a method of mass rearing the predator was developed.
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  • 89
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 3 (1998), S. 63-83 
    ISSN: 1572-9745
    Schlagwort(e): Biosteres ; Coptera ; Diachasmimorpha ; Psyttalia ; Tetrastichus ; augmentation ; host habitat location ; dispersal ; behavioural ecology ; biological control ; classical biological control ; integrated pest management ; mass rearing ; quality control ; parasitoids ; tephritidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The biological control of pest tephritid flies using parasitoids has been successful in relatively few subtropical and tropical regions. The best documented successes were in Hawaii and Florida, USA, Fiji and southern Europe. There were relatively limited successes in Australia, Costa Rica and Mexico. With the accidental establishment of new pest tephritids, such as Bactrocera latifrons (Hendel) in Hawaii or Bactrocera papayae Drew and Hancock in Australia, foreign exploration for new parasitoids is essential. A renewal of interest in classical biological control has recently occurred, although not at the same level as in the 1940s and 1950s. New parasitoid species are currently being obtained for several tephritids, such as Ceratitis capitata (Weidemann), B. latifrons and Anastrepha suspensa (Loew). The advances in mass rearing and quality control technology for parasitoids has enabled researchers to perform large-scale field testing of these parasitoids to determine the potential of augmentative releases. Numerous studies on the augmentative release of parasitoids have been done. Historically, the larval—pupal parasitoid Diachasmimorpha longicaudata (Ashmead) has been the most frequently studied parasitoid, due to the ease of rearing this species. However, recent successes in rearing other species with different biologies, e.g. the egg—pupal parasitoid Biosteres arisanus (Sonan), the gregarious eulophid, Tetrastichus giffardianus (Silvestri) and the pupal parasitoid, Coptera sp., will enable researchers to broaden the repertoire of parasitoid species for the future. Both successes and failures in augmentative releases have occurred. Without knowledge of the behavioural ecology of parasitoids, the reasons for success or failure can only be surmised. Recent research on the dispersal and host habitat finding of tephritid parasitoids will provide insights into improving augmentation and conservation strategies. The integrated pest management (IPM) of tephritid flies in the tropics has been less well-developed than research and programmes for tephritids in temperate zones. Significant emphasis is now being placed on the development of quarantine treatment methods that are environmentally sound; thus IPM will take a larger role. Several existing pest management strategies are reviewed which show the potential for compatibility with the activities of tephritid parasitoids. These include trap cropping, insecticides with selective toxicity to the target pests, mass trapping with parapheromones, the sterile insect technique and field sanitation.
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  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Integrated pest management reviews 3 (1998), S. 225-242 
    ISSN: 1572-9745
    Schlagwort(e): Hypera postica ; alfalfa weevil ; Medicago sativa ; alfalfa ; biological control ; classical biological control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Alfalfa weevil, Hypera postica (Gyllenhall) (Coleoptera: Curculionidae), is of Eurasian origin. This destructive pest of alfalfa (lucerne) was accidentally established in North America on three separate occasions. These introductions are commonly identified in the literature as biological strains: western alfalfa weevil, Egyptian alfalfa weevil (=Hypera brunneipennis Boheman), and eastern alfalfa weevil. Alfalfa weevil has been the target of classical biological control almost since its discovery in North America more than 90 years ago. These efforts have resulted in establishment of at least nine exotic parasitoids and egg predators: Bathyplectes curculionis (Thomson), B. anurus (Thomson) and B. stenostigma (Thomson) (Hymenoptera: Ichneumonidae); Microctonus aethiopoides Loan and M. colesi Drea (Hymenoptera: Braconidae), the latter of undetermined origin; Oomyzus incertus (Ratzenberg) (Hymenoptera: Eulophidae); Dibrachoides dynastes (Forester) and Peridesmia discus (Walker) (Hymenoptera: Pteromalidae); and Anaphes luna (Girault) (Hymenoptera: Mymaridae). A fungal pathogen, Zoophthora phytonomi Arthur (Phycomycetes: Entomophthoraceae), of undetermined origin, is becoming an increasingly important alfalfa weevil mortality factor. Most major USA alfalfa production areas now benefit from a complex of alfalfa weevil biological control agents. Collectively, these agents have effected substantial reduction in the economic importance of alfalfa weevil across the northern USA However, biological agents provide only partial control of alfalfa weevil, and importance of their contribution differs considerably with production area. Still, the benefits achieved, especially from reduced need for insecticides in alfalfa production, mark this as one of the great success stories of classical biological control in North America.
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  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Journal of insect conservation 2 (1998), S. 253-261 
    ISSN: 1572-9753
    Schlagwort(e): Orthoptera ; insecticide ; biological control ; pest management.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Wissenschaftskunde und Wissenschaftsorganisation, Hochschul- und Universitätswesen, Museumswissenschaft
    Notizen: Abstract Although the vast majority of orthopterans are not pests, some species have the potential to cause serious damage to human interests. Management of pest populations frequently conflicts with conservation of orthopteran species and processes, particularly when the pest species or its ecological processes are susceptible to extinction or when the pest population is coincident with non-target orthopterans. With respect to chemical control, the greatest hazards are the broad-spectrum, highly lethal properties of most agents, which can be mitigated with formulation and application methods. Biological control risks permanent, large-scale changes to orthopteran species and processes which can be minimized with bioinsecticidal and other short-lived or selective formulations and reliable host-range testing. Cultural control may have large-scale, broad-spectrum impacts to non-target orthopterans, but these hazards can be diminished by appropriate testing and monitoring. Mechanical control methods may be impractically labour intensive, but they are highly target specific and therefore warrant further consideration. Social control measures such as education, insurance and compensation programmes appear to have little direct potential for harm to orthopteran conservation, but the complex socioeconomic and, ultimately, environmental consequences of such programmes have not been assessed. The melding of orthopteran pest management and conservation requires that we perceive these insects and their ecological processes to be vital elements of sustainable agroecosystems. Our management of orthopterans (both non-target and pest populations) must focus on keeping good stewards on the land.
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  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 41 (1998), S. 117-125 
    ISSN: 1871-4528
    Schlagwort(e): α-solanine ; α-chaconine ; C:S ratio ; glycoalkaloid content ; tuber size ; individual tubers ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Plants of early potato cultivars were sampled at successive harvests during tuber development and individual tubers were analysed for α-solanine and α-chaconine using high-performance liquid chromatography. Mean tuber total glycoalkaloid concentration (α-solanine plus α-chaconine) per plant decreased with time and statistically significant differences between cultivars were observed in the patterns of decline during tuber growth. The mean tuber ratio of α-chaconine to α-solanine increased during tuber development and was also affected by genotype. Total glycoalkaloid concentration for individual tubers of marketable sizes (up to 50 g fresh weight) exceeded the safety limit of 20 mg per 100 g fresh weight for cultivars Home Guard and British Queen but not for Rocket. These differences were attributable to differences in both rates and patterns of glycoalkaloid accumulation during tuber development, although in all cultivars results were consistent with glycoalkaloid accumulation occurring in the expanding peripheral cell layers of tubers for a considerable period after tuber initiation.
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  • 93
    ISSN: 1871-4528
    Schlagwort(e): ratio ; root-shoot ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Potato, wheat and sugar beet were grown in a growth chamber in tanks with flowing solutions containing K-concentrations of 1.5, 5, 15, 50 and 200 μM to find reasons for different K contents of solution needed to reach 90% maximum dry matter accumulation (external K requirement). All species showed variation in dry matter accumulation with varying K levels. To reach 90% maximum dry matter accumulation potato needed 40 μM K, whereas wheat and sugar beet needed 6.4 and 4.4 μM K respectively. These differences in external K requirement could not be explained by differences in their internal K requirement since the internal requirement of potato (7.7% K) was about one and a half times of that of sugar beet (5.4%) but its external requirement was nine times of that of sugar beet. At low K supply potato plants showed a lower influx and a reduced root growth as compared with wheat and sugar beet.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 41 (1998), S. 311-317 
    ISSN: 1871-4528
    Schlagwort(e): Solanum tuberosum L. ; general combining ability ; specific combining ability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary In an epiphytotic year of early blight, data were recorded on its incidence in 72 progenies (18 females x 4 males) and their parents planted in a randomised complete block design at the Punjab Agricultural University, Ludhiana, India. Combining ability analysis showed that both additive and non-additive gene action were important, with a preponderance of the latter in the inheritance of resistance to early blight. In general, progenies were as good as or better than mid-parent values. Crosses involving both or at least one parent with good general combining ability resulted in heterotic early blight resistant progenies. Promising parents and crosses were identified.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 41 (1998), S. 1-8 
    ISSN: 1871-4528
    Schlagwort(e): immobilisation ; filter paper ; dot RT-PCR ; print RT-PCR ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary A test procedure for PSTVd is described based on immobilisation of plant sap on filter paper, by dotting or tissue printing followed by RT-PCR. Tests were carried out using primarily and secondarily infected potato plants, primarily infected in vitro plants, and potato tubers. Print PCR was shown to be suitable for testing large samples of potato plants whereas dot PCR is recommended for in vitro plantlets and tuber tissue. Bulking one infected plant to 4 or 9 healthy plants gave reliable results with secondarily infected potato plants, but sometimes the test failed to detect PSTVd in primarily infected in vitro plants. Dotted and printed paper squares could be stored at 4°C for at least 2 weeks in Triton X-100 solution or under dry conditions. Storing at room temperature can lead to unreliable results.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 41 (1998), S. 219-228 
    ISSN: 1871-4528
    Schlagwort(e): homozygous genotypes ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Using potato parental lines homozygous at a locus or loci controlling resistance to potato leafroll virus (PLRV) can give advantages in the selection of resistant forms. In order to identify homozygous diploid clones their test-cross families were evaluated. All the clones that were test-crossed expressed resistance in primarily- and secondarily-infected plants and etiolated sprouts, and were derived from mating genotypes highly resistant to PLRV. Genotypes from test-cross families varied in resistance to PLRV, and one family was found which had only resistant genotypes, suggesting that the resistant parent of this progeny was homozygous at resistance loci. Evidence was gathered that resistance in some diploid clones may result from resistance to virus multiplication as well as restricted virus transport from leaves to tubers.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 41 (1998), S. 277-287 
    ISSN: 1871-4528
    Schlagwort(e): Solanum tuberosum L. ; quality ; bruising ; external ; internal ; model ; index
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Methods for quantifying external damage and bruising can be inaccurate and result in an index that is difficult to interpret. A new index was derived by taking measurements of peeled slices from cv. Record and developing a mathematical model to predict the percentage volume removed per peeler stroke for a range of potato cultivars. It was found that an average of 1.25% of the tuber volume was removed per peeler stroke. By counting the number of peeler strokes to remove damaged tissue and multiplying by 1.25, an estimate of the percentage tuber volume lost due to bruising or external damage can be obtained. The index can accommodate most types of damage and result in an index that is readily understood.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 41 (1998), S. 345-354 
    ISSN: 1871-4528
    Schlagwort(e): tuber blight ; Solanum tuberosum L. ; disease assessment ; fungal pathogenicity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Variation in aggressiveness to tubers among isolates ofPhytophthora infestans sampled from three potato growing regions in the Netherlands was compared. Variation in the ability to infect tubers of cv. Bintje was found between isolates of each of the three regional populations. The most aggressive isolate of the old population matched the average level of the new population in its ability to infect tubers. As a consequence, the commonly used reference isolate VK 6C can no longer be considered to be representative of the present population ofP. infestans. Therefore it is recommended that testing tuber resistance for the official list of potato cultivars with this isolate should be discontinued. Tuber infection and subsequent spread of the fungus in the tuber tissues were not found to be correlated. The components of tuber pathogenicity studied were not correlated to pathogenicity factors in the foliage, as measured under growth chamber conditions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 99
    ISSN: 1871-4528
    Schlagwort(e): alcohol dehydrogenase ; phosphoglucose isomerase ; sugar assay ; Solanum tuberosum L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Artefactual results were obtained during assay of sugars in ethanolic extracts of potato tubers with the microplate method. The problem was attributed to contamination with alcohol dehydrogenase of the commercial (yeast) phosphoglucose isomerase used in the assay. The use of phosphoglucose isomerase from another source (rabbit muscle) eliminated the problem.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Potato research 41 (1998), S. 21-28 
    ISSN: 1871-4528
    Schlagwort(e): Solanum tuberosum L. ; general combining ability ; seedling generation ; clonal generations ; genotypexenvironment ; yield ; tuber colour and shape
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary General combining ability and its repeatability in the early generations of a potato breeding programme was studied by evaluating 72 progenies (18×4) of 22 parents in a factorial mating design for three successive generations. The mean squares for combining ability due to females, males and females × males were significant for eight out of the ten characters studied. Variance estimates due to specific combining ability were more important than those due to general combining ability for most of the characters in all the generations. General combining ability effects varied from generation to generation. Most of the correlation coefficients between generations for general combining ability effects were significant, but of moderate magnitude (0.5–0.8). Parents with consistent performance over generations and those specifically suitable for a TPS crop were identified.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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