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International Centre of Insect Physiology and Ecology

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Articles 961 - 990 of 1129

Full-Text Articles in Entomology

Release Of Cotesia Flavipes Cameron For Biological Control Of Cereal Stemborers In Two Ecological Zones In Mozambique, D. Cugala, W. A. Overholt, L. Santos, D. Giga Jan 2001

Release Of Cotesia Flavipes Cameron For Biological Control Of Cereal Stemborers In Two Ecological Zones In Mozambique, D. Cugala, W. A. Overholt, L. Santos, D. Giga

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Cotesiaflavipes Cameron (Hymenoptera: Braconidae), a gregarious larval endoparasitoid of Cliilo parleUus (Swinhoe) (Lepidoptera: Crambidae) and other stemborers in the Indo-Australian region, was released in Mozambique for the first time in 1996. Before its release, countrywide surveys on stemborers and their natural enemies were conducted in several places. However, all led to the same conclusion: that Ch. partellns was the most abundant stemborer at the majority of locations, and that the rate of larval parasitism was very low (< 5 %). To evaluate the effect of stemborer species composition on- the establishment of Co. flavipes, two releases were made at two agroecologically different sites during the 1998/1999 and 1999/2000 growing seasons. Cotesiaflavipes was recovered from all the three stemborer species found at each site during the season of release and a year later. However, the rates of parasitism were very low, ranging from 0.6 to 1.9 % on Cli. partellus, 3.2 % on Sesamia calamislis Hampson (Lepidoptera: Noctuidae) and 2.6 % on Busseolafiisca Fuller (Lepidoptera: Noctuidae). The native natural enemy, Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae) was the most common larval parasitoid at the two sites. The recoveries of Co. flavipes during the release period and a year later indicate that this exotic parasitoid has become established at the two locations in the southern and central regipns of Mozambique, in spite of differences in stemborer species composition. However, it is too early to evaluate the impact of Co.flai'ipes on the stemborer populations. © 2001 ICIPE.

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Comparative Development, Longevity And Population Growth Of Exotic And Native Parasitoids Of Lepidopteran Cereal Stemborers In Kenya, J. C. Mbapila, W. A. Overholt Jan 2001

Comparative Development, Longevity And Population Growth Of Exotic And Native Parasitoids Of Lepidopteran Cereal Stemborers In Kenya, J. C. Mbapila, W. A. Overholt

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Studies on the effect of temperature on the development, longevity and population growth of Cotesia flavipes Cameron and Cotesia sesamiae (Cameron) indicated that the development of both Cotesia spp. from oviposition to cocoon formation and adult emergence was inversely related to temperature. The longevity of the parasitoids was also inversely related to temperature. Both parasitoids lived longer when moisture and food (agar + honey/water) were provided. The mean number of females and total adult progeny produced by C. flavipes on two host species were, in most cases, higher than C. sesamiae. The intrinsic rate of natural increase of C. flavipes …

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Habitat Management Strategies For The Control Of Cereal Stemborers And Striga In Maize In Kenya, Z. R. Khan, J. A. Pickett, L. Wadhams, F. Muyekho Jan 2001

Habitat Management Strategies For The Control Of Cereal Stemborers And Striga In Maize In Kenya, Z. R. Khan, J. A. Pickett, L. Wadhams, F. Muyekho

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Maize is the principal food and cash crop for millions of people in the predominantly mixed crop-livestock farming systems in Kenya. Stemborers and striga (Striga hermonthica) are major constraints to increased maize production in eastern Africa. An intercropping and trap crop system has been developed, using a ‘push-pull’ strategy, for the control of stemborers in small scale maize farming systems. The ‘push-pull’ strategy involves trapping stemborers on highly susceptible trap plants (pull) and driving them away from the crop using repellent intercrops (push). Napier grass (Pennisetum piirpiirenm Schumach) and Sudan grass (Sorghum vulgare sudanense Stapf J are used as trap …

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Cereal Stemborer Species Complex And Establishment Of Cotesia Flavipes Cameron In Eastern Uganda, T. Matama-Kauma, S. Kyamanywa, J. A. Ocwang, C. O. Omwega, H. R. Willson Jan 2001

Cereal Stemborer Species Complex And Establishment Of Cotesia Flavipes Cameron In Eastern Uganda, T. Matama-Kauma, S. Kyamanywa, J. A. Ocwang, C. O. Omwega, H. R. Willson

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Studies were conducted in two districts of eastern Uganda from 1997 to 1999 to introduce and monitor the establishment of an exotic parasitoid, Cotesia flavipes Cameron (Hymenoptera: Braconidae), for the control of the stemborer Chilo partellns (Swinhoe) (Lepidoptera: Pyralidae), and also to determine the stemborer species complex in maize and sorghum. The study confirmed the presence of four important stemborers, two pyralids Ch. parlellus and Eldana saccharina Walker and two noctuids, Busseola fusca Fuller and Sesamia calamistis Hampson. Chilo partellus was dominant, constituting 53-88% of stemborers found followed by B.fiisca at 8-37 %. The most abundant local parasitoid was the …

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The Chemical Ecology Of Host Location By Parasitoids Of African Stemborers, Linnet S. Gohole, Adele J. Ngi-Song Jan 2001

The Chemical Ecology Of Host Location By Parasitoids Of African Stemborers, Linnet S. Gohole, Adele J. Ngi-Song

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During foraging, parasitoids of insect herbivores are aided by chemical compounds generally termed ‘infochemicals‘, to locate their hosts. The origin of the infochemicals varies; they may be derived from the herbivore itself or activities related to the biology of the herbivore, the host plant, or from interactions between the plant and the herbivore. This paper reviews the status of research in this area, and presents an account of the infochemicals used by African stemborer parasitoids during foraging, as well as recommending possible areas for further investigation. The information generated has potential for application in behaviour modification of parasitoids species in …

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Pathogenicity And Antifeedant Activity Of Entomopathogenic Hyphomycetes To The Cowpea Leaf Beetle, Ootheca Mutabilis Shalberg, S. Ekesi Jan 2001

Pathogenicity And Antifeedant Activity Of Entomopathogenic Hyphomycetes To The Cowpea Leaf Beetle, Ootheca Mutabilis Shalberg, S. Ekesi

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Conidial suspensions of four isolates each of Bcauvcria bassiana and Melnrhizhtm anisopliae were evaluated in the laboratory for their virulence to adult Ootlicca mntabilis. All the isolates tested were pathogenic to the beetle, but to varying degrees. Three of them, B. bassiana CPD 3 and CPD10 and M. anisopliae CPD 6 were superior to all other isolates in terms of mortality induced on adult beetle, LT50 and LC50, with B. bnssiana CPD 3 having the lowest LC50 value. In feeding assayi consumption by beetles treated with B. bnssiana CPD 3 was significantly reduced within 2 days treatment (DAT) and the …

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Relationships Of Stemborer Damage And Plant Physical Conditions To Maize Yield In A Semi-Arid Zone Of Eastern Kenya, Josephine Moraa Songa, Zhou Guofa, William Allan Overholt Jan 2001

Relationships Of Stemborer Damage And Plant Physical Conditions To Maize Yield In A Semi-Arid Zone Of Eastern Kenya, Josephine Moraa Songa, Zhou Guofa, William Allan Overholt

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A field survey on maize stemborers, stemborer damage, maize plant physical conditions, and maize yield was conducted in eastern Kenya under natural conditions. Chilo partellus was the dominant stemborer accounting for 89.5 % of all borers. Stemborer damage greatly reduced maize yield, with tunnel lengths greater than 20 cm causing a 40 % reduction of potential yield. A 33 % yield loss was found in plants with more than one stemborer exit hole. Each stemborer (at harvest time) was correlated with a 8-10 % yield loss. Good plant physical characteristics significantly increased grain yield. Principle component analysis showed that stemborer …

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Variation In Lipophorin Titres During Development In Solitarious And Gregarious Schistocerca Gregaria (Forskàl) (Orthoptera: Acrididae), D. O. Ogoyi, E. O. Osir Jan 2001

Variation In Lipophorin Titres During Development In Solitarious And Gregarious Schistocerca Gregaria (Forskàl) (Orthoptera: Acrididae), D. O. Ogoyi, E. O. Osir

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The levels of lipophorin, the principal insect haemolymph lipoprotein, were estimated during the development of solitary and gregarious phases of Schistocerca gregaria using single radial immunodiffusion. In the gregarious phase, lipophorin titres ranged from 6.69 ±0.57 mg/ml in the 3rd nymphal instar to 14.42 ±2.04 mg/ml in mature adults. The titres in the solitary phase were 3.33 ± 0.59 mg/ml in the 3rd nymphal instar and 8.44 + 0.67 mg/ml in mature adults. Peak lipophorin titres occurred in mature adults (14.42 ±2.04 mg/ml) and 5th nymphal instar (8.75 ±0.25 mg/ml) for gregarious and solitary locusts, respectively. Gregarious locusts had significantly …

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Changes In The Distribution Of Lepidopteran Maize Stemborers In Kenya From The 1950s To 1990s, Zhou Guofa, William A. Overholt, Moses B. Mochiah Jan 2001

Changes In The Distribution Of Lepidopteran Maize Stemborers In Kenya From The 1950s To 1990s, Zhou Guofa, William A. Overholt, Moses B. Mochiah

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Three hundred and ninety-two maize fields in the southern arable zone of Kenya were sampled for lepidopteran cereal stemborers from 1996-2000. Chilo partelhis (Swinhoe) was the most abundant stemborer, and was found at all locations with elevations below 1500 m, and at some locations between 1500 and 2300 m. The highest density of C. partelhis was in the semi-arid ecological zone of eastern Kenya. Chilo orichalcociliellus (Strand) was found in the lowland southern coastal area, and a few inland sites on the border of Tanzania in southeastern Kenya. Busseola fusca Fuller was dominant in highland areas. In the Lake Victoria …

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Distribution And Species Composition Of Cereal Stemborers In The Eastern Zone Of Tanzania, E. Nsami, B. Pallangyo, V. Mcoo, C. O. Omwega Jan 2001

Distribution And Species Composition Of Cereal Stemborers In The Eastern Zone Of Tanzania, E. Nsami, B. Pallangyo, V. Mcoo, C. O. Omwega

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A survey was conducted in the four regions of Tanga, Morogoro, Coast and Dar es Salaam in eastern Tanzania to determine the distribution and species composition of cereal stemborers and their natural enemies. A total of 22 fields were sampled in Tanga, 28 in Morogoro, 17 in Coast and one in Dar es Salaam. Chilo parlellns was found to be the predominant species, accounting for 80 % of all stemborers collected. Bnsseolafnsca, Sesamia calamistis and Chilo orichalcociliellus made up 15,4 and less than 1 % of the stemborers collected respectively. Infestation levels varied with the age of the plants, whereby …

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Farmers’ Perceptions Of Importance, Control Methods And Natural Enemies Of Maize Stemborers At The Kenya Coast, M. J. Bonhof, A. Van Huis, F. G. Kiros, N. Dlbogo Jan 2001

Farmers’ Perceptions Of Importance, Control Methods And Natural Enemies Of Maize Stemborers At The Kenya Coast, M. J. Bonhof, A. Van Huis, F. G. Kiros, N. Dlbogo

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A survey among 240 resource-poor farmers at the Kenya coast indicated that insect pests were considered to be the main production constraint. Over 70% of respondents mentioned stemborers to be the most important insect pest. Unlike the eggs and adults, stemborer larvae and pupae were frequently seen by farmers. Alternative gramineous host plants for pests were common near maize fields and were often not destroyed until after the first rains. Nearly all farmers left dry stems and stubble in the field after harvest. Farmers knew of many methods for controlling stemborers, but only 32 and 56% of farmers in Kilifi …

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Impact Of Solar Radiation Rainfall And Cannibalism On Disappearance Of Maize Stemborers In Kenya, M. J. Bonhof, W. A. Overholt Jan 2001

Impact Of Solar Radiation Rainfall And Cannibalism On Disappearance Of Maize Stemborers In Kenya, M. J. Bonhof, W. A. Overholt

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The effect of solar radiation, rainfall and cannibalism on the disappearance of eggs and larvae of the cereal stemborer Chilo partellus (Swinhoe) were studied. Disappearance and nonviability of egg batches was higher on plants exposed to solar radiation than on shaded plants. Significantly fewer small larvae were recovered from plants exposed to rainfall than from shielded plants. Cannibalism among larvae of the same size was not common except at high larval densities. Contrary to the common belief that disappearance is the result of prédation, these studies show that solar radiation and rainfall might also play an important role in the …

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Distribution And Abundance, In Maize And Sorghum, Of Lepidopteran Stemborers And Associated Indigenous Parasitoids In Zanzibar, E. I. Nlyibigira, Z. S. Abdallah, W. A. Overholt Jan 2001

Distribution And Abundance, In Maize And Sorghum, Of Lepidopteran Stemborers And Associated Indigenous Parasitoids In Zanzibar, E. I. Nlyibigira, Z. S. Abdallah, W. A. Overholt

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Studies to determine the relative abundance and distribution of stemborer species and their associated parasitoids in maize and sorghum were carried out during the 1995-1996 and 19992000 cropping seasons on Unguja and Pemba, the two main islands of Zanzibar. Three stemborer species were found on both islands in maize and sorghum, with the exotic species Chilo partellns (Swinhoe) (Crambidae) being the most abundant and widely distributed species, accounting for 75.3 % of stemborer attack. It was followed by Sesamia calamistis Hampson (Noctuidae) and C/i. oriclialcociliellus Strand (Crambidae). Stemborer abundance was significantly higher in Pemba (1.47 ± 0.20) than Unguja (0.85 …

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Stemborer Research In Zimbabwe: Prospects For The Establishment Of Cotesia Flavipes Cameron, P. Clhnwada, C. O. Omvvega, W. A. Overholt Jan 2001

Stemborer Research In Zimbabwe: Prospects For The Establishment Of Cotesia Flavipes Cameron, P. Clhnwada, C. O. Omvvega, W. A. Overholt

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The stemborers Busseola fnsca (Fuller) and Chilo partellus (Svvinhoe) cause the highest economic damage to maize and sorghum in Zimbabwe. A number of studies on stemborer bioecology and management in Zimbabwe have been conducted, but most are still incomplete. The more important of these are studies on life history, incidence and distribution patterns, host plants, yield losses, chemical control, cultural control, host plant resistance, the use of sex pheromones, and biological control. These are discussed here in detail, and areas where further research is needed are pointed out. As part of an integrated strategy for managing stemborers in Zimbabwe, an …

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Biosystematics Of The Psyttalia Concolor Species Complex (Hymenoptera: Braconidae: Opiinae): The Identity Of Populations Attacking Ceratitis Capitata (Diptera: Tephritidae) In Coffee In Kenya, S. W. Kimani-Njogu, M. K. Trostle, R. A. Wharton, J. B. Woolley, A. Raspi Jan 2001

Biosystematics Of The Psyttalia Concolor Species Complex (Hymenoptera: Braconidae: Opiinae): The Identity Of Populations Attacking Ceratitis Capitata (Diptera: Tephritidae) In Coffee In Kenya, S. W. Kimani-Njogu, M. K. Trostle, R. A. Wharton, J. B. Woolley, A. Raspi

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The identity of a species of Psyttalia, a parasitoid of tephritid fruit flies in Kenya, was investigated. Individuals reared from coffee infested with Ceratitis capitata (Wiedemann) (Medfly) and two other tephritid species in Kenya were compared with individuals of Psyttalia concolor (Szépligeti) from a laboratory culture in Italy used in augmentative biological control of olive fly, Bactrocera oleae (Gmelin). Reciprocal crosses showed full compatibility, with production of viable female offspring. A preliminary morphometric analysis demonstrated that most individuals originating from Italy could be separated from most of those from Kenya based largely on differences in overall size.

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Host Suitability Of Four Cereal Stem Borers (Lepidoptera: Crambidae, Noctuidae) For Different Geographic Populations Of Cotesia Sesamiae (Cameron) (Hymenoptera: Braconidae) In Kenya, Moses B. Mochiah, Adele J. Ngi-Song, William A. Overholt, M. Botchey Jan 2001

Host Suitability Of Four Cereal Stem Borers (Lepidoptera: Crambidae, Noctuidae) For Different Geographic Populations Of Cotesia Sesamiae (Cameron) (Hymenoptera: Braconidae) In Kenya, Moses B. Mochiah, Adele J. Ngi-Song, William A. Overholt, M. Botchey

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This study focused on the suitability of four species of cereal stem borers for the development of five geographic populations of Cotesia sesamiae (Cameron). C. sesamiae, an indigenous larval parasitoid of gramineous stem borers, is widespread in Africa. Four stem borers, Chilo partellus (Swinhoe), Chilo orichalcociliellus Strand (Lepidoptera: Crambidae), Busseola fusca Fuller, and Sesamia calamistis Hampson (Lepidoptera: Noctuidae), were offered to C. sesamiae for oviposition. Parasitoid individuals originated from five locations in Kenya. Biological parameters such as developmental time, percentage parasitism, progeny production, mortality of immature parasitoids, and proportion of female progeny were compared across host species. The two populations …

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Spatial And Temporal Distribution Of Tsetse Fly Trap Catches At Nguruman, Southwest Kenya, A. Odulaja, J. Baumgärtner, S. Mihok, I. M. Abu-Zinid Jan 2001

Spatial And Temporal Distribution Of Tsetse Fly Trap Catches At Nguruman, Southwest Kenya, A. Odulaja, J. Baumgärtner, S. Mihok, I. M. Abu-Zinid

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Spatial and temporal dynamics of rapidly growing populations of tsetse flies at Nguruman, southwest Kenya during 1993-1995, were investigated, following six years of intensive population suppression with traps over a c. 100 km2 area. The two tsetse species present were randomly distributed in the short rainy season, but were aggregated in the dry and long rainy seasons. Maximum temperature was the dominant weather factor associated with the degree of aggregation. Trends in catches at 20 fixed sites along an 18 km north-south axis were weakly correlated between locations, possibly representing population sub-structuring. In particular, trends in population change were poorly …

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Greenhouse Trials Of New Bacillus Thuringiensis Isolates For Control Of Chilo Partellus Larvae In Sorghum, Michael Brownbridge Jan 2001

Greenhouse Trials Of New Bacillus Thuringiensis Isolates For Control Of Chilo Partellus Larvae In Sorghum, Michael Brownbridge

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Eight new Bacillus thuringiensis Berliner (Bt) isolates originally recovered from different source materials and geographic locations in Kenya were tested against Chilo partellus (Swinhoe) on sorghum grown in a greenhouse. All isolates had been demonstrated previously to be toxic to this pest. Bt strains were cultured in a liquid growth medium and preserved as powders for experimental application. Three-week-old sorghum plants (4-6 leaves) were artificially infested with 20 neonate C. partellus and sprayed 24 h later with Bt suspensions. Non-infested sorghum and infested non-treated sorghum served as the comparative checks within each experimental trial. Plant development and dead-heart formation were …

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Distribution And Species Composition Of Stemborers And Their Natural Enemies In Maize And Sorghum In Ethiopia, Emana Getu, W. A. Overholt, E. Kairu Jan 2001

Distribution And Species Composition Of Stemborers And Their Natural Enemies In Maize And Sorghum In Ethiopia, Emana Getu, W. A. Overholt, E. Kairu

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Surveys were conducted to determine the species composition of stemborers and their natural enemies in maize and sorghum in 1999 and 2000 in eastern, northern, southern and western Ethiopia. The six species of stemborers found attacking maize and sorghum were Cltilp partellus (Swinhoe) (Lepidoptera: Crambidae), Busseolafiisca Fuller, Sesamia calamistis Hampson (Lepidoptera: Noctuidae), S. nonagrioides botanephaga Tarns and Bowden (Lepidoptera: Noctuidae), Rhynchaenus niger (Horn) (Coleoptera: Rhynchophoridae) and Pissodes dubious (Stroöm) (Coleoptera: Rhynchophoridae). Twenty species of primary parasitoids of eggs, larvae and pupae of Ch. partellus, B. fusca and S. calamistis were recorded. Other natural enemies, including predators, fungi and nematodes, were …

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Insect Pests And Beneficial Arthropod Populations Under Different Hedgerow Intercropping Systems In Semiarid Kenya, H. Girma, M. R. Rao, S. Sithanantham Dec 2000

Insect Pests And Beneficial Arthropod Populations Under Different Hedgerow Intercropping Systems In Semiarid Kenya, H. Girma, M. R. Rao, S. Sithanantham

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Exploiting the principles of biological control of crop pests is an important management strategy for the resource-poor smallholder farmers of the tropics. The effects of nine hedgerow species on the abundance of major insect pests of beans and maize, and predatory/parasitic-arthropods were monitored over two cropping seasons and the intervening dry period. The tree/shrub species evaluated were Gliricidia sepium, Grevillea robusta, Senna siamea, Senna spectabilis, Flemingea congesta, Croton megalocarpus, Morus alba, Calliandra calothyrsus and Lantana camara. Arthropod abundance was monitored through counts of infested plants and using yellow pan and pitfall traps. Beanfly (Ophiomyia spp.) infestation was significantly higher in …

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Time-Course Haemolymph Juvenile Hormone Titres In Solitarious And Gregarious Adults Of Schistocerca Gregaria, And Their Relation To Pheromone Emission, Ca Volumetric Changes And Oocyte Growth, Amer I. Tawfik, Karl Treiblmayr, Ahmed Hassanali, E. O. Osir Jul 2000

Time-Course Haemolymph Juvenile Hormone Titres In Solitarious And Gregarious Adults Of Schistocerca Gregaria, And Their Relation To Pheromone Emission, Ca Volumetric Changes And Oocyte Growth, Amer I. Tawfik, Karl Treiblmayr, Ahmed Hassanali, E. O. Osir

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The haemolymph JH III titres in solitarious and gregarious adult desert locusts, Schistocerca gregaria, were examined in relation to corpus allatum (CA) volumes, aggregation-maturation pheromone production in males and oocyte growth in females. The JH titres of gregarious females were generally higher than those of solitarious females at all ages studied. The titre patterns, however, were similar: relatively high on day 10, dropping to low levels between days 20 and 25, before rising again by day 25. In the solitarious males, the JH titre was very low on day 10 after fledging, but increased gradually and reached a maximal amount …

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Parturition Hormone In The Tsetse Glossina Morsitans: Activity In Reproductive Tissues From Other Species And Response Of Tsetse To Identified Neuropeptides And Other Neuroactive Compounds, Jan Žďárek, Ronald J. Nachman, David L. Denlinger Mar 2000

Parturition Hormone In The Tsetse Glossina Morsitans: Activity In Reproductive Tissues From Other Species And Response Of Tsetse To Identified Neuropeptides And Other Neuroactive Compounds, Jan Žďárek, Ronald J. Nachman, David L. Denlinger

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Parturition hormone (PH) activity is present not only in the uterus of the tsetse Glossina morsitans but also in the oviducts of Bombyx mori and Schistocerca gregaria, as well as the ejaculatory duct of S. gregaria males. Activity thus appears to be present in the reproductive ducts of diverse insect taxa. To determine whether any the common insect neuropeptides are capable of mimicking the effect of PH, 35 identified neuropeptides and analogs were evaluated for PH activity. Modest PH activity was observed for only high doses of proctolin and a pyrokinin analog, thus suggesting that PH is unlikely to be …

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The Role Of Different Components Of The Pheromone Emission Of Mature Males Of The Desert Locust, Schistocerca Gregaria (Forskâl) (Orthoptera: Acrididae) In Accelerating Maturation Of Immature Adults, Hassane Mahamat, Ahmed Hassanali, Hezekiel Odongo Jan 2000

The Role Of Different Components Of The Pheromone Emission Of Mature Males Of The Desert Locust, Schistocerca Gregaria (Forskâl) (Orthoptera: Acrididae) In Accelerating Maturation Of Immature Adults, Hassane Mahamat, Ahmed Hassanali, Hezekiel Odongo

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Different blends of five chromatographically prominent components of the pheromone emission of gregarious-phase mature desert locust Schistocerca gregaria (Forskâl) (Orthoptera: Acrididae) males were bioassayed for their maturation-accelerating effects on immature counterparts. The blend of all five components, namely anisole, veratrole, benzaldehyde, phenylacetonitrile and 4-vinylveratrole was as effective as the emission from live mature males in accelerating the onset of mating in immature males. Subtraction of anisole had no significant effect but removal of any one of the other four components significantly reduced the acceleration potency of the resulting blends. The maximum reduction occurred in the absence of phenylacetonitrile which appears …

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Parasitoids Of Medfly, Ceratitis Capitata, And Related Tephritids In Kenyan Coffee: A Predominantly Koinobiont Assemblage, R. A. Wharton, M. K. Trostle, R. H. Messing, R. S. Copeland, S. W. Kimani-Njogu, S. Lux, W. A. Overholt, S. Mohamed, J. Sivinski Jan 2000

Parasitoids Of Medfly, Ceratitis Capitata, And Related Tephritids In Kenyan Coffee: A Predominantly Koinobiont Assemblage, R. A. Wharton, M. K. Trostle, R. H. Messing, R. S. Copeland, S. W. Kimani-Njogu, S. Lux, W. A. Overholt, S. Mohamed, J. Sivinski

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Arabica coffee was sampled from two sites in the central highlands of Kenya (Rurima, Ruiru) and one site on the western side of the Rift Valley (Koru). Three species of ceratitidine Tephritidae, Ceratitis capitata (Wiedemann), C. rosa Karsch and Trirhithrum coffeae Bezzi, were reared from sites in the central highlands, and an additional species, C. anonae Graham, was recovered from the western-most site. Ten species of parasitic Hymenoptera were reared from these tephritids. The parasitoid assemblage was dominated by koinobionts. Eight of the species are koinobiont endoparasitoids, but only one idiobiont larval ectoparasitoid was reared, and only one idiobiont pupal …

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Evaluation Of Banana Cultivars For Resistance To The Banana Weevil Cosmopolites Sordidus And Nematode Complex In Western Kenya, T. Musabyimana, K. V. Seshu Reddy, L. Ngode, J. S. Prasad Jan 2000

Evaluation Of Banana Cultivars For Resistance To The Banana Weevil Cosmopolites Sordidus And Nematode Complex In Western Kenya, T. Musabyimana, K. V. Seshu Reddy, L. Ngode, J. S. Prasad

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Banana weevil Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) and parasitic nematodes are often together on the same banana mat. Both pests have been recognized as major constraints to banana production. They may cause up to 85% yield loss in banana. Hence, both pests should be investigated together to define a control strategy for this complex constraint. With this view, our investigation was carried out in a naturally nematode-weevil infested farmer's field to search for host plant resistance to both pests. Pratylenchus goodeyi, Helicotylenchus multicinctus and Meloidogyne spp. were the most commonly occurring nematodes in the experiment and were often in mixed …

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Cattle And Amblyomma Variegatum Odors Used In Host Habitat And Host Finding By The Tick Parasitoid, Ixodiphagus Hookeri, Fanuel A. Demas, Ahmed Hassanali, Esther N. Mwangi, Edna C. Kunjeku, Audrey R. Mabveni Jan 2000

Cattle And Amblyomma Variegatum Odors Used In Host Habitat And Host Finding By The Tick Parasitoid, Ixodiphagus Hookeri, Fanuel A. Demas, Ahmed Hassanali, Esther N. Mwangi, Edna C. Kunjeku, Audrey R. Mabveni

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The response of mated naive Ixodiphagus hookeri females to cattle and Amblyomma variegatum nymphal odors was tested in a Y-tube olfactometer. I. hookeri females were attracted to cattle urine, dung, and odors from tick- free feeding sites of A. variegatum nymphs on cattle, e.g., dewlaps, front heels, and hind heels. Tick-free scrotal odors did not attract the parasitoids. Furthermore, odors from off-host unfed and fed A. variegatum nymphs did not attract the parasitoids, despite an increase in the number of the nymphs to amplify any odor signal. A blend of odors from feeding on-host nymphs and cattle scrota attracted the …

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Powdered Neem Seed And Cake For Management Of The Banana Weevil, Cosmopolites Sordidus, And Parasitic Nematodes, T. Musabyimana, R. C. Saxena, E. W. Kairu, C. K.P.O. Ogol, Z. R. Khan Jan 2000

Powdered Neem Seed And Cake For Management Of The Banana Weevil, Cosmopolites Sordidus, And Parasitic Nematodes, T. Musabyimana, R. C. Saxena, E. W. Kairu, C. K.P.O. Ogol, Z. R. Khan

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Field trials were conducted in Kenya with 'Nakyetengu', an East African highland banana cultivar (AAA-EA), highly susceptible to banana pests. Regardless of soil fertility levels, incorporation around the plant base of powdered neem (Azadirachta indica A. Juss.) seed or cake at 60-100 g/mat at 4-month intervals, gave better control of the banana weevil, Cosmopolites sordidus (Germar), and of parasitic nematodes, than that achieved with soil application of Furadan 5G (carbofuran) at 60 g/mat at 6-month intervals. Compared with untreated control, fruit yield in most of the neem treatments was significantly higher, particularly during the second cycle of crop production. Neem …

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Changing Oviposition Preferences Of The Desert Locust, Schistocerca Gregaria, Suggest A Strong Species Predisposition For Gregarization, M. O. Bashir, A. Hassanali, M. M. Rai, R. K. Saini Jan 2000

Changing Oviposition Preferences Of The Desert Locust, Schistocerca Gregaria, Suggest A Strong Species Predisposition For Gregarization, M. O. Bashir, A. Hassanali, M. M. Rai, R. K. Saini

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Field surveys at five sites within desert locust breeding habitats around Port Sudan during three successive seasons indicated that early in the rainy season the incoming solitary females oviposited predominantly in the vicinity of Heliotropium spp. (~66%) and millet (~32%) seedlings. Solitary nymphs also preferred to feed on these plants. Follow-up cage experiments were conducted in the field in which solitary and gregarious female locusts were presented with choices of selected desert plants and egg pods. When presented with bulrush millet, Heliotropium spp., Zygophyllum simplex, and untreated moistened sand, solitary females oviposited adjacent to the first two plants (40% and …

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Susceptibility Of The Legume Flower Thrips To Metarhizium Anisopliae On Different Varieties Of Cowpea, S. Ekesi, N. K. Maniania, W. Lwande Jan 2000

Susceptibility Of The Legume Flower Thrips To Metarhizium Anisopliae On Different Varieties Of Cowpea, S. Ekesi, N. K. Maniania, W. Lwande

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The susceptibility of Megalurothrips sjostedti to Metarhizium anisopliae when reared on susceptible, tolerant, and moderately resistant varieties of cowpea at different constant temperatures was evaluated in the laboratory. Insects were exposed either to direct spray of the conidia or to fungus-treated floral tissues. Mortality was significantly higher on the moderately resistant variety at all temperatures compared to the susceptible and tolerant varieties. Correspondingly, lethal time and lethal concentration values were significantly shorter and lower, respectively, on the moderately resistant variety compared to the other varieties, thus indicating that the two control methods are compatible as part of an integrated pest …

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Effect Of Volatiles And Crude Extracts Of Different Plant Materials On Egg Viability Of Maruca Vitrata And Clavigralla Tomentosicollis, S. Ekesi Jan 2000

Effect Of Volatiles And Crude Extracts Of Different Plant Materials On Egg Viability Of Maruca Vitrata And Clavigralla Tomentosicollis, S. Ekesi

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The effect of volatiles and aqueous extracts of black pepper, Piper guineense; neem seed, Azadirachta indica; garlic bulb, Allium sativum; and onion bulb, Allium cepa on egg viability of Maruca vitrata Fab. (Lepidoptera: Pyralidae) and Clavigralla tomentosicollis Stal (Heteroptera: Coreidae) was evaluated in laboratory experiments. Compared with the other treatments, volatiles of black pepper and garlic bulb were superior in reducing hatch of freshly laid (12-h-old) eggs of both species of insects. Volatiles of onion bulb and neem seed had no effect on egg hatch. When aqueous extracts of the various plant materials were tested at 5%, 10% and 15%, …

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