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Articles 2221 - 2250 of 2421

Full-Text Articles in Life Sciences

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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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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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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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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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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Determination Of Wax Concentration In Sunflower-Seed Oil, Silvana Martini, M.C. Anon Oct 2000

Determination Of Wax Concentration In Sunflower-Seed Oil, Silvana Martini, M.C. Anon

Nutrition, Dietetics, and Food Sciences Faculty Publications

Isothermal crystallization of waxes was studied by using an optical setup. The induction time of crystallization was assessed as a function of wax concentration. The relationship was found to be a decreasing exponential curve. The wax content of some of the solutions prepared in the laboratory was determined by calculating the crystallization induction time. The values obtained were compared to those from different methods (cold test, microscopic, and turbidimetric methods). The results obtained with the optical setup method are similar to those obtained with other methods for concentrations greater than 100 ppm. An analysis of variance test was used to …

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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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History, Religion And Meaning: American Reflections On The Holocuast And Israel, Jules Simon Jan 2000

History, Religion And Meaning: American Reflections On The Holocuast And Israel, Jules Simon

Departmental Papers (Philosophy)

No abstract provided.

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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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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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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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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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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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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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Simulation Model For Maize Crop Growth Based On Acquisition And Allocation Processes For Carbohydrate And Nitrogen, O. Bonato, F. Schulthess, J. Baumgärtner Dec 1999

Simulation Model For Maize Crop Growth Based On Acquisition And Allocation Processes For Carbohydrate And Nitrogen, O. Bonato, F. Schulthess, J. Baumgärtner

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A population model for maize growth and development driven by temperature, solar radiation, soil water and soil nitrogen is presented. A time-varying distributed delay model is used to describe the dynamics of the attributes number, biomass and nitrogen belonging to leaf, root, stem, grain, rachys and husk populations. Photosynthate production as well as water and nitrogen acquisition was simulated with a demand-driven ratio-dependent functional response model. Carbohydrate, water and nitrogen supply-demand ratios were calculated to control the growth of different populations of plant. The metabolic pool model was used to allocate carbohydrates to plant subunits. The model was validated with …

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Selection Of Virulent Isolates Of Entomopathogenic Hyphomycetes Against Clavigralla Tomentosicollis Stål. And Evaluation In Cage Experiment Using Three Cowpea Varieties, S. Ekesi Dec 1999

Selection Of Virulent Isolates Of Entomopathogenic Hyphomycetes Against Clavigralla Tomentosicollis Stål. And Evaluation In Cage Experiment Using Three Cowpea Varieties, S. Ekesi

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The virulence of 8 isolates of entomopathogenic hyphomycetes against adult and 5th instar nymph of Clavigralla tomentosicollis was evaluated in the laboratory at 4 different concentrations of inoculum. At all concentrations, Beauveria bassiana CPD 9 and Metarhizium anisopliae CPD 5 caused the highest mortality in adult bug ranging from 58 to 97% and 53 to 100%, respectively at 7 days post inoculation. The same isolates had the shortest LT50 (3.5 and 4.1 days, respectively) and the lowest LC50 (1.8 × 105 and 9.8 × 104 conidia ml-1) values in adult insects. In nymphs, M. anisopliae CPD 5 was the most …

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Cleome Hirta Essential Oil As Livestock Tick (Rhipicephalus Appendiculatus) And Maize Weevil (Sitophilus Zeamais) Repellent, M. W. Ndungu, S. C. Chhabra, W. Lwande Oct 1999

Cleome Hirta Essential Oil As Livestock Tick (Rhipicephalus Appendiculatus) And Maize Weevil (Sitophilus Zeamais) Repellent, M. W. Ndungu, S. C. Chhabra, W. Lwande

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The repellency of the essential oil of the shrub Cleome hirta and of three identified constituents (phytol, (+)-cedrol, n-octacosane) was evaluated against the livestock tick, Rhipicephalus appendiculatus and the maize weevil, Sitophillus zeamais. In a tick climbing repellency bioassay, the oil exhibited repellency which, at the highest dose, was comparable to that of the commercial arthropod repellent N,N-diethyltoluamide (DEET). In a Y-tube olfactometer bioassay, the oil showed higher or comparable repellency against S. zeamais relative to DEET at all the doses tested. The potential of C. hirta in livestock tick and maize weevil control is discussed. Copyright (C) 1999 Elsevier …

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Infochemicals In Mosquito Host Selection: Human Skin Microflora And Plasmodium Parasites, Marieta A.H. Braks, Robert A. Anderson, Bart G.J. Knols Oct 1999

Infochemicals In Mosquito Host Selection: Human Skin Microflora And Plasmodium Parasites, Marieta A.H. Braks, Robert A. Anderson, Bart G.J. Knols

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The interaction between the African malaria vector Anopheles gambiae and its human host has traditionally been viewed within a bitrophic context, considering only the human and the mosquito. Recently, the influence of the Plasmodium parasite on the interaction has been recognized, because it affects the physiology and/or behaviour of humans and mosquitoes. However, studies on odour-mediated host-seeking behaviour of An. gambiae and other Diptera have provided evidence that a fourth group of organisms should be taken into consideration. Human skin microflora play a role in the production of odorous compounds that might function as kairomones for mosquitoes. Here, Marieta Braks, …

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The Effects Of A Tsetse Dna Virus Infection On The Functions Of The Male Accessory Reproductive Gland In The Host Fly Glossina Morsitans Centralis (Diptera; Glossinidae), Rosemary C. Sang, Walter G.Z.O. Jura, Leonard H. Otieno, Richard W. Mwangi, Peter Ogaja Jun 1999

The Effects Of A Tsetse Dna Virus Infection On The Functions Of The Male Accessory Reproductive Gland In The Host Fly Glossina Morsitans Centralis (Diptera; Glossinidae), Rosemary C. Sang, Walter G.Z.O. Jura, Leonard H. Otieno, Richard W. Mwangi, Peter Ogaja

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Freshly deposited third instar Glossina morsitans centralis larvae were infected with the tsetse DNA virus by microinjection, and at emergence adult males were separated from the females and fed on rabbit blood every second day for 8 days. A control group treated with sterile saline were handled similarly. They were dissected, and comparative observations made on the appearance and size of the accessory reproductive glands (ARG) in infected and control males. Regularly fed 8-day-old males from infected and control groups were mated to 2-day-old normal females obtained from the insectay. After separation from copula, the females were dissected and the …

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Isolation Of Trypanosoma Brucei From The Monitor Lizard (Varanus Niloticus) In An Endemic Focus Of Rhodesian Sleeping Sickness In Kenya, Zipporah Njagu, Steve Mihok, Elizabeth Kokwaro, Didier Verloo Mar 1999

Isolation Of Trypanosoma Brucei From The Monitor Lizard (Varanus Niloticus) In An Endemic Focus Of Rhodesian Sleeping Sickness In Kenya, Zipporah Njagu, Steve Mihok, Elizabeth Kokwaro, Didier Verloo

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Monitor lizards were sampled along the shores of Lake Victoria to detect natural infections of potentially human-infective trypanosomes. In an area with endemic rhodesian sleeping sickness, one of 19 lizards was infected (Busia, Kenya). Six of ten lizards also showed indirect evidence of infection with Trypanosoma brucei (antibody ELISA). In an area with no recent history of human disease (Rusinga Island), no parasites were found and no antibodies to T. brucei were detected. The isolate was identified as T. brucei through xenodiagnosis (completion of the life cycle in the salivary glands of tsetse), and through molecular techniques (positive reactions with …

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Trypanosome Infection Rate In Cattle At Nguruman, Kenya, R. A. Tarimo-Nesbitt, T. K. Golder, R. D. Dransfield, M. F. Chaudhury, R. Brightwell Feb 1999

Trypanosome Infection Rate In Cattle At Nguruman, Kenya, R. A. Tarimo-Nesbitt, T. K. Golder, R. D. Dransfield, M. F. Chaudhury, R. Brightwell

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Trypanosome infection rate in cattle at Nguruman was investigated in a study conducted in 1984-1986. Shifting pastoralism significantly reduced trypanosome infections in cattle. The cattle were more heavily infected with Trypanosoma congolense (16.5%) than Trypanosoma vivax (4.95%) and Trypanosoma brucei (0.19%). Trypanosoma theileri was observed only once among the cattle examined. Mixed trypanosome infections in cattle were observed to be 2.75% and 0.014% for T. congolense/T. vivax and T. congolense/T. brucei, respectively. The duration of infection in the cattle was 55 days for T. congolense and 79 days for T. vivax. High infections in cattle were observed 2 months after …

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Responses Of Glossina Fuscipes Fuscipes (Diptera: Glossinidae) And Other Diptera To Carbon Dioxide In Linear And Dense Forests, M. M. Mohamed-Ahmed, S. Mihok Jan 1999

Responses Of Glossina Fuscipes Fuscipes (Diptera: Glossinidae) And Other Diptera To Carbon Dioxide In Linear And Dense Forests, M. M. Mohamed-Ahmed, S. Mihok

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The responses of Glossina fuscipes fuscipes Newstead and other Diptera to carbon dioxide were studied in linear and dense forests along the shores of Lake Victoria, Kenya. Flies were caught in biconical traps and were intercepted with electric nets while in flight near traps. Carbon dioxide dispensed at a high rate (51 min-1) in linear forest failed to increase the numbers of tsetse attracted to or caught in traps. In contrast, catches of non-biting Muscidae, Stomoxyinae and Tabanidae were improved by up to 11 times. Inside dense forest, carbon dioxide released at half this rate increased both the numbers of …

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Isozyme Polymorphism In Some Yellow-And Blue-Flowered Vigna Species Complexes (Fabaceae, Phaseoleae), Remy S. Pasquet, Thierry Vanderborght Jan 1999

Isozyme Polymorphism In Some Yellow-And Blue-Flowered Vigna Species Complexes (Fabaceae, Phaseoleae), Remy S. Pasquet, Thierry Vanderborght

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An electrophoretic comparison of variation at 28 isozyme loci was performed for 58 Vigna accessions belonging to the V. luteola, V. ambacensis, and V. racemosa groups of species. In all three groups, strong divergence is noted between results and actual nomenclature.

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Comparative Evaluation Of Cotesia Flavipes And C. Sesamiae (Hymenoptera: Braconidae) For The Management Of Chilo Partellus (Lepidoptera: Pyralidae) In Kenya, M. N. Sallam, W. A. Overholt, E. Kairu Jan 1999

Comparative Evaluation Of Cotesia Flavipes And C. Sesamiae (Hymenoptera: Braconidae) For The Management Of Chilo Partellus (Lepidoptera: Pyralidae) In Kenya, M. N. Sallam, W. A. Overholt, E. Kairu

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Cotesia flavipes Cameron, a gregarious larval endoparasitoid native to the Indo-Australian region, was imported from Pakistan and released in Kenya in 1993 for management of the exotic stemborer, Chilo partellus (Swinhoe). Recent reports confirmed the successful establishment of the parasitoid in three locations in Kenya and in northern Tanzania. Functional response studies on this parasitoid and an indigenous congener, Cotesia sesamiae (Cameron), indicated that C. flavipes had a higher searching ability and attacked more larvae when Chilo partellus was the host. When a native stemborer, Sesamia calamistis Hampson, was the host, there was no significant difference between numbers attacked by …

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Efficacy Of Neem Seed Derivatives Against Nematodes Affecting Banana, T. Musabyimana, R. C. Saxena Jan 1999

Efficacy Of Neem Seed Derivatives Against Nematodes Affecting Banana, T. Musabyimana, R. C. Saxena

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Soil applications of powdered neem seed or neem cake at 100 g/plant at planting and, subsequently, at 3-month intervals, reduced the populations of Pratylenchus goodeyi Sher and Allen and Meloidogyne spp. on par with Furadan 5G (carbofuran) applied at 40 g/plant at planting and then at 6-month intervals to banana plants grown in 100-l containers with controlled levels of banana nematode infestations. Eight months after planting, banana plants treated with powdered neem cake, seed or kernel or with neem oil had 4 to 95 times fewer parasitic nematodes than the untreated control. However, only neem cake powder or neem seed …

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Insights For The Management Of Different Locust Species From New Findings On The Chemical Ecology Of The Desert Locust, Ahmed Hassanali, Magzoub Omer Bashir Jan 1999

Insights For The Management Of Different Locust Species From New Findings On The Chemical Ecology Of The Desert Locust, Ahmed Hassanali, Magzoub Omer Bashir

All Peer-Reviewed Publications

Recent studies on the chemical ecology of the desert locust, Schistocerca gregaria, have unravelled a rich and complex system of pheromonal and other semiochemical-mediated communication in this insect. The key pheromones associated with such behavioural processes as social cohesion and communal egg-laying have been characterised. The semiochemical bases of such physiological processes as maturation of solitarious insects before the arrival of seasonal rains, development of gregarious traits in crowded solitarious insects, development of maturation synchrony in gregarious insects, and maternal transfer of gregarious characters to the offspring are better understood. Desert locust semiochemicals are finding two principal uses: as tools …

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