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  • 1
    Electronic Resource
    Electronic Resource
    Evidence of controlled corpus allatum activity in the adult Colorado potato beetle
    Amsterdam : Elsevier
    Journal of Insect Physiology 25 (1979), S. 449-453 
    Details
    ISSN: 0022-1910
    Keywords: Colorado potato beetle ; Leptinotarsa decemlineata (Say) ; corpus allatum ; endocrine control ; hormone titres ; juvenile hormone
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0022-1910(79)90013-1
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  • 2
    Electronic Resource
    Electronic Resource
    The impact of the egg parasitoid Uscana lariophaga on Callosobruchus maculatus populations and the damage to cowpea in a traditional storage system (1998)
    Springer
    Entomologia experimentalis et applicata 89 (1998), S. 289-295 
    Details
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Trichogrammatidae ; Uscana lariophaga ; Coleoptera ; Bruchidae ; Callosobruchus maculatus ; cowpea ; storage pest ; biological control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003555413273
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  • 3
    Electronic Resource
    Electronic Resource
    Niche overlap and interspecific association between Chilo partellus and Chilo orichalcociliellus on the Kenya coast (1999)
    Springer
    Entomologia experimentalis et applicata 93 (1999), S. 141-148 
    Details
    ISSN: 1570-7458
    Keywords: Chilo partellus ; Chilo orichalcociliellus ; niche overlap ; interspecific competition ; interspecific association ; competitive displacement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chilo partellus (Swinhoe) and Chilo orichalcociliellus Strand (Lepidoptera: Crambidae) occur sympatrically on the Kenya coast and are injurious to maize and sorghum. Evidence over a period of 30 years indicates that the indigenous stem borer, C. orichalcociliellus, is being gradually displaced by the exotic stem borer, C. partellus. The two species have overlapping niches, but the specific mechanisms driving the displacement are unknown. The distribution and extent of niche overlap and interspecific association between C. partellus and C. orichalcociliellus were investigated in cultivated and wild host plants. No difference in the within-plant distribution of the two borer species in maize and sorghum was found. A niche overlap of 83.7% between C. partellus and C. orichalcociliellus was found. A weak positive association was found between small-, medium-, and large-sized larvae of C. partellus and C. orichalcociliellus. However, as larvae grew, the association decreased with no significant association at the pupal stage. No negative association was found between C. partellus and C. orichalcociliellus, suggesting that the two species do not avoid or directly harm each other. The partial displacement of C. orichalcociliellus may therefore, be attributed to intrinsically superior attributes of C. partellus that indirectly affect the survival of C. orichalcociliellus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003844318375
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  • 4
    Electronic Resource
    Electronic Resource
    Egg mortality of rice leaf folders Cnaphalocrocis medinalis and Marasmia patnalisin irrigated rice fields (1999)
    Springer
    BioControl 44 (1999), S. 451-473 
    Details
    ISSN: 1573-8248
    Keywords: Anaxipha longipennis ; biological control ; Gryllidae ; Metioche vitatticollis ; parasitism ; predation ; Trichogramma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: 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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009915621547
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  • 5
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    Pest Management Strategies in Traditional Agriculture: An African Perspective (2000)
    Annual Reviews
    Details
    Publication Date: 2000-01-01
    Description: ▪ Abstract  African agriculture is largely traditional—characterized by a large number of smallholdings of no more than one ha per household. Crop production takes place under extremely variable agro-ecological conditions, with annual rainfall ranging from 250 to 750 mm in the Sahel in the northwest and in the semi-arid east and south, to 1500 to 4000 mm in the forest zones in the central west. Farmers often select well-adapted, stable crop varieties, and cropping systems are such that two or more crops are grown in the same field at the same time. These diverse traditional systems enhance natural enemy abundance and generally keep pest numbers at low levels. Pest management practice in traditional agriculture is a built-in process in the overall crop production system rather than a separate well-defined activity. Increased population pressure and the resulting demand for increased crop production in Africa have necessitated agricultural expansion with the concomitant decline in the overall biodiversity. Increases in plant material movement in turn facilitated the accidental introduction of foreign pests. At present about two dozen arthropod pests, both introduced and native, are recognized as one of the major constraints to agricultural production and productivity in Africa. Although yield losses of 0% to 100% have been observed on-station, the economic significance of the majority of pests under farmers’ production conditions is not adequately understood. Economic and social constraints have kept pesticide use in Africa the lowest among all the world regions. The bulk of pesticides are applied mostly against pests of commercial crops such as cotton, vegetables, coffee, and cocoa, and to some extent for combating outbreaks of migratory pests such as the locusts. The majority of African farmers still rely on indigenous pest management approaches to manage pest problems, although many government extension programs encourage the use of pesticides. The current pest management research activities carried out by national or international agricultural research programs in Africa focus on classical biological control and host plant resistance breeding. With the exception of classical biological control of the cassava mealybug, research results have not been widely adopted. This could be due to African farmers facing heterogeneous conditions, not needing fixed prescriptions or one ideal variety but a number of options and genotypes to choose from. Indigenous pest management knowledge is site-specific and should be the basis for developing integrated pest management (IPM) techniques. Farmers often lack the biological and ecological information necessary to develop better pest management through experimentation. Formal research should be instrumental in providing the input necessary to facilitate participatory technology development such as that done by Farmer Field Schools, an approach now emerging in different parts of Africa.
    Print ISSN: 0066-4170
    Electronic ISSN: 1545-4487
    Topics: Biology
    Published by Annual Reviews
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