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Full-Text Articles in Life Sciences

Thermal Tolerance Of The Coffee Berry Borer Hypothenemus Hampei: Predictions Of Climate Change Impact On A Tropical Insect Pest, Juliana Jaramillo, Adenirin Chabi-Olaye, Charles Kamonjo, Alvaro Jaramillo, Fernando E. Vega, Hans Michael Poehling, Christian Borgemeister Aug 2009

Thermal Tolerance Of The Coffee Berry Borer Hypothenemus Hampei: Predictions Of Climate Change Impact On A Tropical Insect Pest, Juliana Jaramillo, Adenirin Chabi-Olaye, Charles Kamonjo, Alvaro Jaramillo, Fernando E. Vega, Hans Michael Poehling, Christian Borgemeister

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Coffee is predicted to be severely affected by climate change. We determined the thermal tolerance of the coffee berry borer , Hypothenemus hampei, the most devastating pest of coffee worldwide, and make inferences on the possible effects of climate change using climatic data from Colombia, Kenya, Tanzania, and Ethiopia. For this, the effect of eight temperature regimes (15, 20, 23, 25, 27, 30, 33 and 35°C) on the bionomics of H. hampei was studied. Successful egg to adult development occurred between 20-30°C. Using linear regression and a modified Logan model, the lower and upper thresholds for development were estimated at …

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Recilia Banda Kramer (Hemiptera: Cicadellidae), A Vector Of Napier Stunt Phytoplasma In Kenya, Evans Obura, Charles A.O. Midega, Daniel Masiga, John A. Pickett, Mohamed Hassan, Shinsaku Koji, Zeyaur R. Khan Jul 2009

Recilia Banda Kramer (Hemiptera: Cicadellidae), A Vector Of Napier Stunt Phytoplasma In Kenya, Evans Obura, Charles A.O. Midega, Daniel Masiga, John A. Pickett, Mohamed Hassan, Shinsaku Koji, Zeyaur R. Khan

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Napier grass (Pennisetum purpureum) is the most important fodder crop in smallholder dairy production systems in East Africa, characterized by small zero-grazing units. It is also an important trap crop used in the management of cereal stemborers in maize in the region. However, production of Napier grass in the region is severely constrained by Napier stunt disease. The etiology of the disease is known to be a phytoplasma, 16SrXI strain. However, the putative insect vector was yet unknown. We sampled and identified five leafhopper and three planthopper species associated with Napier grass and used them as candidates in pathogen transmission …

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Anti-Mosquito And Antimicrobial Nor-Halimanoids, Isocoumarins And An Anilinoid From Tessmannia Densiflora, Charles Kihampa, Mayunga H.H. Nkunya, Cosam C. Joseph, Stephen M. Magesa, Ahmed Hassanali, Matthias Heydenreich, Erich Kleinpeter Jul 2009

Anti-Mosquito And Antimicrobial Nor-Halimanoids, Isocoumarins And An Anilinoid From Tessmannia Densiflora, Charles Kihampa, Mayunga H.H. Nkunya, Cosam C. Joseph, Stephen M. Magesa, Ahmed Hassanali, Matthias Heydenreich, Erich Kleinpeter

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The nor-halimane diterpenoid tessmannic acid and its methyl, 2-methylisopropyl and 1-methylbutyl esters, the unusual isocoumarins 8-hydroxy-6-methoxy-3-pentylisocoumarin and 7-chloro-8-hydroxy-6-methoxy-3-pentylisocoumarin, and 5-pentyl-3-methoxy-N-butylaniline were isolated from the stem and root bark extracts of Tessmannia densiflora Harms (Caesalpiniaceae) that showed mosquito larvicidal activity. The structures were determined on interpretation of spectroscopic data. Tessmannic acid and its methyl ester exhibited antibacterial and antifungal activity. The compounds also caused high larvae and adult Anopheles gambiae mosquitoe mortality effects, and stronger mosquito repellency than that shown by the standard repellent DEET, hence indicating Tessmannia species to be potential sources of bioactive natural products. © 2009 Elsevier Ltd. …

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Collective Batesian Mimicry Of Ant Groups By Aggregating Spiders, Ximena J. Nelson, Robert R. Jackson Jul 2009

Collective Batesian Mimicry Of Ant Groups By Aggregating Spiders, Ximena J. Nelson, Robert R. Jackson

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Many predators are averse to attacking ants and many palatable arthropods are Batesian mimics of ants. We considered whether aggregating Batesian mimics of ants can become more repelling to ant-averse predators by, as a group, resembling groups of ants (collective mimicry). Myrmarachne melanotarsa is a gregarious ant-like jumping spider (Salticidae) that resembles and associates with the ant Crematogaster sp. We used three large ant-averse salticids as predators in experiments. Besides M. melanotarsa and Crematogaster we used midges (Chaoborus sp.) and a small nonant-like, but gregarious, salticid (Menemerus sp.) as prey. The predators readily attacked both live midges and the nonant-like …

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Predation And Reproductive Output Of The Ladybird Beetle Stethorus Tridens Preying On Tomato Red Spider Mite Tetranychus Evansi, Erika P.J. Britto, Manoel G.C. Gondim, Jorge B. Torres, Komi K.M. Fiaboe, Gilberto J. Moraes, Markus Knapp Jun 2009

Predation And Reproductive Output Of The Ladybird Beetle Stethorus Tridens Preying On Tomato Red Spider Mite Tetranychus Evansi, Erika P.J. Britto, Manoel G.C. Gondim, Jorge B. Torres, Komi K.M. Fiaboe, Gilberto J. Moraes, Markus Knapp

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Predatory behaviour and reproductive output of the ladybird beetle Stethorus tridens Gordon as function of the tomato red spider mite (TRSM), Tetranychus evansi Baker & Pritchard, densities was investigated in the laboratory. Adult female of S. tridens were isolated in cylindrical plastic arenas, containing a leaf disc of Solanum americanum Mill. with 5, 20, 40, 60, 80 or 100 T. evansi nymphs. The number of prey consumed and eggs laid were evaluated daily for ten consecutive days, starting at the oviposition. Oviposition of S. tridens was positively correlated with prey consumption and lower threshold prey consumption for S. tridens laying …

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White Lupin Leads To Increased Maize Yield Through A Soil Fertility-Independent Mechanism: A New Candidate For Fighting Striga Hermonthica Infestation?, Laure Weisskopf, Pollycarp Akello, Roxane Milleret, Zeyaur R. Khan, Fritz Schulthess, Jean Michel Gobat, Renée Claire Le Bayon Jun 2009

White Lupin Leads To Increased Maize Yield Through A Soil Fertility-Independent Mechanism: A New Candidate For Fighting Striga Hermonthica Infestation?, Laure Weisskopf, Pollycarp Akello, Roxane Milleret, Zeyaur R. Khan, Fritz Schulthess, Jean Michel Gobat, Renée Claire Le Bayon

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Nitrogen (N)-deficiency and lack of phosphorus (P) availability are major constraints to maize yields in Western Kenya. In a two-season field study in the lake Victoria basin, we tested the capacity of white lupin (Lupinus albus (L.), cv. Ultra), as a nitrogen-fixing crop with a highly efficient P-acquisition capacity, to increase maize yields when used as a companion or cover crop, or as a source of organic matter. Each experiment was performed on three different fields (Vertisols) differing in N/P availability, previous cropping history and in levels of infestation by the parasitic weed Striga hermonthica (Del.) Benth. Our results show …

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Where To Sample? Ecological Implications Of Sampling Strata In Determining Abundance And Impact Of Natural Enemies Of The Coffee Berry Borer, Hypothenemus Hampei, Juliana Jaramillo, Adenirin Chabi-Olaye, Christian Borgemeister, Charles Kamonjo, Hans Michael Poehling, Fernando E. Vega Jun 2009

Where To Sample? Ecological Implications Of Sampling Strata In Determining Abundance And Impact Of Natural Enemies Of The Coffee Berry Borer, Hypothenemus Hampei, Juliana Jaramillo, Adenirin Chabi-Olaye, Christian Borgemeister, Charles Kamonjo, Hans Michael Poehling, Fernando E. Vega

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Several parasitoids of African origin have been introduced to coffee producing areas of the Americas and Asia as biological control agents of the coffee berry borer (CBB) Hypothenemus hampei (Coleoptera: Curculionidae). These parasitoids have become established in the field but their effect on the CBB has been limited. A two-year field study in Western Kenya has found Prorops nasuta (Hymenoptera: Bethylidae) to be the predominant parasitoid emerging from CBB-infested coffee berries collected on coffee trees or from the ground. P. nasuta comprises more than 75% of the total natural enemies collected. The density of P. nasuta was 90% higher in …

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Diversity, Distribution And Role Of Wild Crucifers In Major Cabbage And Kale Growing Areas Of Kenya, R. Kahuthia-Gathu, B. Löhr, H. M. Poehling, P. K. Mbugua Jun 2009

Diversity, Distribution And Role Of Wild Crucifers In Major Cabbage And Kale Growing Areas Of Kenya, R. Kahuthia-Gathu, B. Löhr, H. M. Poehling, P. K. Mbugua

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An investigation of the diversity and distribution of wild crucifer species and their importance for cultivated crucifers was conducted during 2005 and 2006 in the highland and mid-altitude semi-arid areas of Kenya. Thirteen species of wild crucifers in nine genera were recorded: Raphanus raphanistrum, Erucastrum arabicum, Sisymbrium officinale, Crambe kilimandscharica, Capsella bursa-pastoris, Rorippa nudiuscula, Ro. micrantha, Ro. microphylla, Lepidium bonariense, Coronopus didymus, Brassica rapa, B. juncea and an unidentified Brassica species. Highland areas had significantly higher species diversity and species richness than mid-altitude semi-arid areas. Species richness, diversity and evenness varied with season and location. Raphanus raphanistrum was the dominant …

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Prospects For Developing Odour Baits To Control Glossina Fuscipes Spp., The Major Vector Of Human African Trypanosomiasis, Maurice O. Omolo, Ahmed Hassanali, Serge Mpiana, Johan Esterhuizen, Jenny Lindh, Mike J. Lehane, Philippe Solano, Jean Baptiste Rayaisse, Glyn A. Vale, Steve J. Torr, Inaki Tirados May 2009

Prospects For Developing Odour Baits To Control Glossina Fuscipes Spp., The Major Vector Of Human African Trypanosomiasis, Maurice O. Omolo, Ahmed Hassanali, Serge Mpiana, Johan Esterhuizen, Jenny Lindh, Mike J. Lehane, Philippe Solano, Jean Baptiste Rayaisse, Glyn A. Vale, Steve J. Torr, Inaki Tirados

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We are attempting to develop cost-effective control methods for the important vector of sleeping sickness, Glossina fuscipes spp. Responses of the tsetse flies Glossina fuscipes fuscipes (in Kenya) and G. f. quanzensis (in Democratic Republic of Congo) to natural host odours are reported. Arrangements of electric nets were used to assess the effect of cattle-, human- and pig-odour on (1) the numbers of tsetse attracted to the odour source and (2) the proportion of flies that landed on a black target (1 × 1 m). In addition responses to monitor lizard (Varanus niloticus) were assessed in Kenya. The effects of …

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Bed Net Use And Associated Factors In A Rice Farming Community In Central Kenya, Peter N. Ng'ang'a, Gayathri Jayasinghe, Violet Kimani, Josephat Shililu, Charity Kabutha, Lucy Kabuage, John Githure, Clifford Mutero May 2009

Bed Net Use And Associated Factors In A Rice Farming Community In Central Kenya, Peter N. Ng'ang'a, Gayathri Jayasinghe, Violet Kimani, Josephat Shililu, Charity Kabutha, Lucy Kabuage, John Githure, Clifford Mutero

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Background. Use of insecticide-treated nets (ITNs) continues to offer potential strategy for malaria prevention in endemic areas. However their effectiveness, sustainability and massive scale up remain a factor of socio-economic and cultural variables of the local community which are indispensable during design and implementation stages. Methods. An ethnographic household survey was conducted in four study villages which were purposefully selected to represent socio-economic and geographical diversity. In total, 400 households were randomly selected from the four study villages. Quantitative and qualitative information of the respondents were collected by use of semi-structured questionnaires and focus group discussions. Results. Malaria was reported …

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Mate-Odour Identification By Both Sexes Of Evarcha Culicivora, An East African Jumping Spider, Fiona R. Cross, Robert R. Jackson May 2009

Mate-Odour Identification By Both Sexes Of Evarcha Culicivora, An East African Jumping Spider, Fiona R. Cross, Robert R. Jackson

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Evarcha culicivora is an unusual salticid spider because each sex actively courts the other and both sexes make distinctive mate-choice decisions. Here we use olfactometer experiments for investigating the ability of each sex to identify potential mates on the basis of odour alone. Test spiders spent more time in the vicinity of opposite-sex conspecific source spiders, regardless of whether or not these source spiders had previously mated, when the alternatives were conspecific individuals of the same sex, juveniles or a control (no odour source). This trend held regardless of the test spider's and source spider's age after reaching maturity and, …

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Variability In Pheromone Communication Among Different Haplotype Populations Of Busseola Fusca, A. E. Félix, G. Genestier, C. Malosse, P. A. Calatayud, B. Le Rü, J. F. Silvain, B. Frérot May 2009

Variability In Pheromone Communication Among Different Haplotype Populations Of Busseola Fusca, A. E. Félix, G. Genestier, C. Malosse, P. A. Calatayud, B. Le Rü, J. F. Silvain, B. Frérot

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The relationship between pheromone composition and mitochondrial haplotype clades was investigated by coupling DNA analyses with pheromone identification and male mate searching behavior among different geographic populations of Busseola fusca. The within-population variations in pheromone blend were as great as those observed between geographic populations, suggesting that the female sex pheromone blend was not the basis of reproductive isolation between the geographic clades. Furthermore, while data from wind tunnel experiments demonstrated that most of the tested males were sensitive to small variations in pheromone mixture, there was considerable within-population variability in the observed response. The study identified a new pheromone …

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Evaluation Of Farmers' Field Days As A Dissemination Tool For Push-Pull Technology In Western Kenya, David M. Amudavi, Zeyaur R. Khan, Japhether M. Wanyama, Charles A.O. Midega, Jimmy Pittchar, Ahmed Hassanali, John A. Pickett Mar 2009

Evaluation Of Farmers' Field Days As A Dissemination Tool For Push-Pull Technology In Western Kenya, David M. Amudavi, Zeyaur R. Khan, Japhether M. Wanyama, Charles A.O. Midega, Jimmy Pittchar, Ahmed Hassanali, John A. Pickett

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Our earlier study on farmers' adoption of 'Push-pull' technology (PPT) for management of cereal stemborers and Striga weed showed that field days (FDs) could be effective in technology dissemination. Hence, in an effort to utilize effective and economical dissemination strategies, we undertook a detailed study in 2007 to assess their effectiveness in PPT dissemination by interviewing 1492 participants randomly selected during participation in FDs. A majority (80%) of the respondents learnt about the biology and damage caused by stemborers and Striga, how PPT works, how to implement PPT and utilize its products, among others. Consequently, over 70% of them favoured …

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Spatiotemporal Dynamics Of Immature Culicines (Subfamily Culicinae) And Their Larval Habitats In Mwea Rice Scheme, Kenya, Ephantus J. Muturi, Joseph M. Mwangangi, Benjamin G. Jacob, Josephat I. Shililu, Charles M. Mbogo, John I. Githure, Robert J. Novak Mar 2009

Spatiotemporal Dynamics Of Immature Culicines (Subfamily Culicinae) And Their Larval Habitats In Mwea Rice Scheme, Kenya, Ephantus J. Muturi, Joseph M. Mwangangi, Benjamin G. Jacob, Josephat I. Shililu, Charles M. Mbogo, John I. Githure, Robert J. Novak

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An ecological study was conducted at three study sites in Mwea Rice Scheme, Kenya to identify the diverse aquatic habitats in which culicine mosquitoes thrived and to explore the best strategies for mosquito control in the area. During the 11-month study period, ten habitat categories and 11 culicine species mainly dominated by Culex quinquefasciatus (72.0%) and Culex annulioris (17.9%) were identified from pupae and late instars larval samples. Two of the 11 culicine species, Ficalbia (Mimomyia) plumosa and Uranotaenia spp., have not been reported previously in the study area. Rurumi had more habitat types than either of the other study …

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Submicroscopic Gametocytes And The Transmission Of Antifolate-Resistant Plasmodium Falciparum In Western Kenya, Mayke J.A.M. Oesterholt, Michael Alifrangis, Colin J. Sutherland, Sabah A. Omar, Patrick Sawa, Christina Howitt, Louis C. Gouagna, Robert W. Sauerwein, Teun Bousema Feb 2009

Submicroscopic Gametocytes And The Transmission Of Antifolate-Resistant Plasmodium Falciparum In Western Kenya, Mayke J.A.M. Oesterholt, Michael Alifrangis, Colin J. Sutherland, Sabah A. Omar, Patrick Sawa, Christina Howitt, Louis C. Gouagna, Robert W. Sauerwein, Teun Bousema

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Background: Single nucleotide polymorphisms (SNPs) in the dhfr and dhps genes are associated with sulphadoxine-pyrimethamine (SP) treatment failure and gametocyte carriage. This may result in enhanced transmission of mutant malaria parasites, as previously shown for chloroquine resistant parasites. In the present study, we determine the association between parasite mutations, submicroscopic P. falciparum gametocytemia and malaria transmission to mosquitoes. Methodology/Principal Findings: Samples from children treated with SP alone or in combination with artesunate (AS) or amodiaquine were genotyped for SNPs in the dhfr and dhps genes. Gametocytemia was determined by microscopy and Pfs25 RNA-based quantitative nucleic acid sequence-based amplification (Pfs25 QT-NASBA). …

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How Cross-Modality Effects During Intraspecific Interactions Of Jumping Spiders Differ Depending On Whether A Female-Choice Or Mutual-Choice Mating System Is Adopted, Fiona R. Cross, Robert R. Jackson Feb 2009

How Cross-Modality Effects During Intraspecific Interactions Of Jumping Spiders Differ Depending On Whether A Female-Choice Or Mutual-Choice Mating System Is Adopted, Fiona R. Cross, Robert R. Jackson

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An important prediction from game theory is that the value of a resource influences the level to which conflict escalates. Here we use jumping spiders (Salticidae) to consider this prediction in the context of species adopting different mating systems ('female mate-choice' and 'mutual mate-choice'). Our experiments are designed for determining whether the odour of conspecific females, more than the odour of heterospecific females, primes males to escalate conflict with a potential same-sex rival and also whether the odour of conspecific males, more than the odour of heterospecific males, primes females to escalate conflict with a potential same-sex rival. Four species …

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Parasitoids Associated With Mussidia Spp. (Lepidoptera: Pyralidae) In Kenya, Benjamin Kimwele Muli, Fritz Schulthess, Johnnie Van Den Berg Feb 2009

Parasitoids Associated With Mussidia Spp. (Lepidoptera: Pyralidae) In Kenya, Benjamin Kimwele Muli, Fritz Schulthess, Johnnie Van Den Berg

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The pyralid Mussidia nigrivenella, a pest of cotton, maize and Phaseolus bean in West Africa, has never been reported as a crop pest in East and Southern Africa, although reportedly it exists in the wild. It is hypothesized that the difference in pest status of M. nigrivenella between western and eastern Africa was either due to differences in natural enemy compositions or that there exist several populations and/or species of Mussidia, which vary in their host plant range. Thus, a catalogue of parasitoids of Mussidia spp. was established through surveys in mid-altitude and coastal Kenya, between 2006 and 2007. Mussidia …

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Field Release Of A Non-Toxigenic Aspergillus Flavus L Strain In Central Benin, A. M. Klueken, C. Borgemeister, B. Hau Jan 2009

Field Release Of A Non-Toxigenic Aspergillus Flavus L Strain In Central Benin, A. M. Klueken, C. Borgemeister, B. Hau

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Non-toxigenic strains of Aspergillus flavus (Link) can be used as biological control agents to reduce the contamination of grains such as maize with carcinogenic and immunotoxic aflatoxins. Based on its sclerotial morphology, A. flavus is commonly divided into two types: L strains and S strains. In this study, we applied the non-toxigenic A. flavus L strain BN030D to the soil of five maize fields in Djidja, central Benin, to investigate its effects on the composition of the prevailing fungal communities, on the ratio of A. flavus L strains and S strains, and on the vegetative compatibility of L strains with …

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Larvicidal Activity Of Extracts From Three Plumbago Spp Against Anopheles Gambiae, Barasa M. Maniafu, Lwande Wilber, Isaiah O. Ndiege, Cornelius C. Wanjala, Teresa Ayuko Akenga Jan 2009

Larvicidal Activity Of Extracts From Three Plumbago Spp Against Anopheles Gambiae, Barasa M. Maniafu, Lwande Wilber, Isaiah O. Ndiege, Cornelius C. Wanjala, Teresa Ayuko Akenga

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Three Plumbago spp have been tested for mosquito larvicidal activity. The crude extracts exhibiting the highest larvicidal activity against Anopheles gambiae were hexane (LC50 = 6.4 μg/mL) and chloroform (LC50 = 6.7 μg/mL) extracts from Plumbago zeylanica Linn, chloroform (LC50 = 6.7 ug/mL) extract from Plumbago stenophylla Bull and ethyl acetate (LC50 = 4.1 μg/mL) extract from Plumbago dawei Rolfe. These LC50 values were within 95% confidence limits. 5-hydroxy-2-methyl-1,4-naphthoquinone (plumbagin) 1 (LC50 = 1.9 μg/mL) and β-sitosterol 2 were characterised from ethyl acetate extract of root bark of P. dawei, a native medicinal plant growing in Kenya, based on spectral …

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Describing Anopheles Arabiensis Aquatic Habitats In Two Riceland Agro-Ecosystems In Mwea, Kenya Using A Negative Binomial Regression Model With A Non-Homogenous Mean, Benjamin G. Jacob, Daniel Griffith, Ephantus Muturi, Erick X. Caamano, Josephat Shililu, John I. Githure, Robert J. Novak Jan 2009

Describing Anopheles Arabiensis Aquatic Habitats In Two Riceland Agro-Ecosystems In Mwea, Kenya Using A Negative Binomial Regression Model With A Non-Homogenous Mean, Benjamin G. Jacob, Daniel Griffith, Ephantus Muturi, Erick X. Caamano, Josephat Shililu, John I. Githure, Robert J. Novak

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This research illustrates a geostatistical approach for modeling the spatial distribution patterns of Anopheles arabiensis Patton (Patton) aquatic habitats in two riceland environments. QuickBird 0.61m data, encompassing the visible bands and the near-infra-red (NIR) band, were selected to synthesize images of An. arabiensis aquatic habitats. These bands and field sampled data were used to determine ecological parameters associated with riceland larval habitat development. SAS® was used to calculate univariate statistics, correlations and Poisson regression models. Global autocorrelation statistics were generated in ArcGIS® from georeferenced Anopheles aquatic habitats in the study sites. The geographic distribution of Anopheles gambiae s.l. aquatic habitats …

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Effect Of Common Wild Crucifer Species Of Kenya On Fitness Of Two Exotic Diamondback Moth Parasitoids, Cotesia Plutellae And Diadegma Semiclausum, R. Kahuthia-Gathu, B. Löhr, H. M. Poehling Dec 2008

Effect Of Common Wild Crucifer Species Of Kenya On Fitness Of Two Exotic Diamondback Moth Parasitoids, Cotesia Plutellae And Diadegma Semiclausum, R. Kahuthia-Gathu, B. Löhr, H. M. Poehling

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Plutella xylostella is the most abundant and damaging pest of cruciferous crops in Kenya and has gained economic importance over the years. During a survey conducted in the major crucifer areas of Kenya a number of wild crucifers recorded in the region were found infested with diamondback moth. As a result, research was conducted in the laboratory and greenhouse to investigate whether exotic parasitoids recently introduced would develop and survive on the wild crucifers. Experiments were conducted on development, survival, reproductive potential and parasitism of Cotesia plutellae and Diadegma semiclausum on cultivated Brassica (Brassica oleracea var. capitata and B. oleracea …

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Regulation Of Oviposition In Anopheles Gambiae S.S.: Role Of Inter- And Intra-Specific Signals, Leunita A. Sumba, C. Brandon Ogbunugafor, Arop L. Deng, Ahmed Hassanali Nov 2008

Regulation Of Oviposition In Anopheles Gambiae S.S.: Role Of Inter- And Intra-Specific Signals, Leunita A. Sumba, C. Brandon Ogbunugafor, Arop L. Deng, Ahmed Hassanali

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Females of Anopheles gambiae Giles normally oviposit in a large number of fresh, small, sunlit, and spatially spread temporary pools. Such pools are associated with lower levels of predation compared to large, longer-lasting habitats. We compared oviposition levels on preferred (water collected from natural anopheline larval habitats) and non-preferred (distilled water) aqueous substrates by gravid females that contained different densities of conspecific eggs or early and late instar larvae. The presence of conspecific larvae, but not eggs, had a positive or negative effect on the ovipositional responses of gravid An. gambiae females, depending on the quality (preferred or non-preferred by …

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Cross Mating Studies Among Five Fruit Fly Parasitoid Populations: Potential Biological Control Implications For Tephritid Pests, Maxwell K. Billah, Susan W. Kimani-Njogu, Robert A. Wharton, William A. Overholt, David D. Wilson, Millicent A. Cobblah Oct 2008

Cross Mating Studies Among Five Fruit Fly Parasitoid Populations: Potential Biological Control Implications For Tephritid Pests, Maxwell K. Billah, Susan W. Kimani-Njogu, Robert A. Wharton, William A. Overholt, David D. Wilson, Millicent A. Cobblah

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The reproductive compatibility between four different species/populations of the tephritid parasitoid Psyttalia (Walker) species from Kenya and individuals of the morphologically identical Psyttalia concolor (Szépligeti) (Hymenoptera: Braconidae) from a laboratory culture in Italy used in augmentative biological control of olive fly, Bactrocera oleae (Gmelin) (Diptera: Tephritidae) was assessed through cross mating tests using single-pair and group mating methods. Reciprocal crosses among the species resulted in the production of viable offsprings up to the second generation. In spite of the successful production of viable offspring in the laboratory, Psyttalia species are known to have specific host fruit and/or host fly preferences …

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Unforeseen Misuses Of Bed Nets In Fishing Villages Along Lake Victoria, Noboru Minakawa, Gabriel O. Dida, Gorge O. Sonye, Kyoko Futami, Satoshi Kaneko Sep 2008

Unforeseen Misuses Of Bed Nets In Fishing Villages Along Lake Victoria, Noboru Minakawa, Gabriel O. Dida, Gorge O. Sonye, Kyoko Futami, Satoshi Kaneko

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Background. To combat malaria, the Kenya Ministry of Health and nongovernmental organizations (NGOs) have distributed insecticide-treated nets (ITNs) for use over beds, with coverage for children under five years of age increasing rapidly. Nevertheless, residents of fishing villages have started to use these bed nets for drying fish and fishing in Lake Victoria. This study investigated the extent of bed net misuse in fishing villages. Methods. Seven fishing villages along the lake were surveyed to estimate how widely bed nets were being used for fishing and drying fish. Villagers were asked why they used the bed nets for such purposes. …

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Recent Reduction In The Water Level Of Lake Victoria Has Created More Habitats For Anopheles Funestus, Noboru Minakawa, Gorge Sonye, Gabriel O. Dida, Kyoko Futami, Satoshi Kaneko Aug 2008

Recent Reduction In The Water Level Of Lake Victoria Has Created More Habitats For Anopheles Funestus, Noboru Minakawa, Gorge Sonye, Gabriel O. Dida, Kyoko Futami, Satoshi Kaneko

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Background. The water level of Lake Victoria has fallen more than 1.5 m since 1998, revealing a narrow strip of land along the shore. This study determined whether the recent drop in the water level has created additional breeding grounds for malaria vectors. Methods. The recent and past shorelines were estimated using landmarks and a satellite image. The locations of breeding habitats were recorded using a GPS unit during the high and low lake water periods. GIS was used to determine whether the breeding habitats were located on newly emerged land between the new and old shorelines. Results. Over half …

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Resource Allocation And Bionomics Of Indigenous And Exotic Cotesia (Hymenoptera: Braconidae) Species Reared On Sesamia Calamistis, Y. Hailemichael, F. Schulthess, J. Smith, W. Overholt, A. Chabi-Olaye Aug 2008

Resource Allocation And Bionomics Of Indigenous And Exotic Cotesia (Hymenoptera: Braconidae) Species Reared On Sesamia Calamistis, Y. Hailemichael, F. Schulthess, J. Smith, W. Overholt, A. Chabi-Olaye

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The braconid larval parasitoids Cotesia chilonis (Matsumura), C. flavipes Cameron and a strain of Cotesia sesamiae (Cameron) from coastal Kenya, reared at the International Centre of Insect Ecology and Physiology, were introduced at the International Institute of Tropical Agriculture in the Republic of Benin for suitability testing on West African stemborers prior to release. C. chilonis was originally collected in Japan while C. flavipes was imported into Kenya from Pakistan. The host species used was the noctuid Sesamia calamistis (Hampson), the most important noctuid maize pest in the region. All three Cotesia species attacked and successfully developed in 2nd to …

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Role Of Native Bees And Natural Habitats In Eggplant (Solanum Melongena) Pollination In Kenya, Barbara Gemmill-Herren, Alfred O. Ochieng' Aug 2008

Role Of Native Bees And Natural Habitats In Eggplant (Solanum Melongena) Pollination In Kenya, Barbara Gemmill-Herren, Alfred O. Ochieng'

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The pollination requirements of eggplant (Solanum melongena) were investigated. One variety of eggplant exhibited a significantly reduced seed set in absence of pollinators, and two varieties significantly increased seed numbers when pollen deposition was enhanced. Two solitary bee species, Xylocopa caffra and Macronomia rufipes, were identified as effective pollinators of the crop. The visitation rates of these pollinators to eggplant flowers declined significantly with distance from the wild habitat. The importance of wild plants as alternative forage source for pollinators was assessed by a survey of the flowering plants in different habitats surrounding eggplant fields. While ruderal farm weeds provide …

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Economic Performance Of The 'Push-Pull' Technology For Stemborer And Striga Control In Smallholder Farming Systems In Western Kenya, Zeyaur R. Khan, Charles A.O. Midega, Esther M. Njuguna, David M. Amudavi, Japhether M. Wanyama, John A. Pickett Jul 2008

Economic Performance Of The 'Push-Pull' Technology For Stemborer And Striga Control In Smallholder Farming Systems In Western Kenya, Zeyaur R. Khan, Charles A.O. Midega, Esther M. Njuguna, David M. Amudavi, Japhether M. Wanyama, John A. Pickett

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The 'push-pull' technology (PPT), developed in Africa, offers effective control of cereal stemborers and Striga weed in maize-based cropping systems. It involves intercropping maize with desmodium, Desmodium uncinatum, with Napier grass, Pennisetum purpureum, planted as border around this intercrop. Desmodium repels the stemborer moths (push) that are subsequently attracted to the Napier grass (pull). Desmodium also suppresses and eliminates Striga. We assessed economic performance of this technology compared to the conventional maize mono- and maize-bean intercropping systems in six districts in western Kenya over 4-7 years. Ten farmers were randomly recruited in each district and each planted three plots representing …

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Can Low Release Numbers Lead To Establishment And Spread Of An Exotic Parasitoid: The Case Of The Diamondback Moth Parasitoid, Diadegma Semiclausum (Hellén), In East Africa, G. Gichini, B. Löhr, A. Rossbach, B. Nyambo, R. Gathu Jun 2008

Can Low Release Numbers Lead To Establishment And Spread Of An Exotic Parasitoid: The Case Of The Diamondback Moth Parasitoid, Diadegma Semiclausum (Hellén), In East Africa, G. Gichini, B. Löhr, A. Rossbach, B. Nyambo, R. Gathu

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From 2001 onwards, Diadegma semiclausum, an exotic parasitoid of the diamondback moth, was introduced and released in Kenya, Tanzania and Uganda. Contrary to common practice where thousands of parasitoids are released, we released very low numbers, 125 females in Kenya, 160 in Uganda and 350 in Tanzania. About 2 years after this single release, the establishment and natural spread of the parasitoids was assessed in all release areas. Two methods were employed: in Kenya, a grid with equidistant points in the four cardinal directions (2-50 km) with the release area in the centre was used and collections were made 27 …

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Genetic And Biological Variations Among Plutella Xylostella Granulovirus Isolates, S. Subramanian, R. J. Rabindra, S. Sithanantham Jun 2008

Genetic And Biological Variations Among Plutella Xylostella Granulovirus Isolates, S. Subramanian, R. J. Rabindra, S. Sithanantham

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Success of a baculovirus in the field depends on the selection and utilization of effective isolates of viruses with increased pathogenicity and virulence. Isolates of Plutella xylostella granuloviruses collected from Kenya and India were compared for genetic variations by restriction endonuclease enzyme analysis and for biological activity based on their median lethal concentration and time-to-kill early- and late-third instars. The P. xylostella granulovirus isolates in Kenya were more diverse than those in India and were considerably different from the latter, with only 53-61% similarity. The Kenyan and Indian isolates did not differ significantly for their median lethal concentration, but the …

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