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Articles 781 - 810 of 1443

Full-Text Articles in Life Sciences

Chemical Composition Of Cupressus Lusitanica And Eucalyptus Saligna Leaf Essential Oils And Bioactivity Against Major Insect Pests Of Stored Food Grains, Philip K. Bett, Arop L. Deng, Joshua O. Ogendo, Samuel T. Kariuki, Maud Kamatenesi-Mugisha, Joel M. Mihale, Baldwyn Torto Apr 2016

Chemical Composition Of Cupressus Lusitanica And Eucalyptus Saligna Leaf Essential Oils And Bioactivity Against Major Insect Pests Of Stored Food Grains, Philip K. Bett, Arop L. Deng, Joshua O. Ogendo, Samuel T. Kariuki, Maud Kamatenesi-Mugisha, Joel M. Mihale, Baldwyn Torto

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The leaf essential oils from Cupressus lusitanica, Miller and Eucalyptus saligna, Smith obtained by hydrodistillation were analyzed by GC/MS and also screened for their insecticidal and repellent effects against adult Tribolium castaneum, Acanthoscelides obtectus, Sitotroga cerealella and Sitophilus zeamais. The C. lusitanica oil contained mainly umbellulone (18.38%) and α-pinene (9.97%) whereas the E. saligna oil was dominated by α-pinene (24.40%) and 1,8-cineole (24.26%). Bioassays showed that of the four insect species tested, A. obtectus and S. cerealella were the most susceptible to the oils, with LC50 values of 0.05-0.11% v/w in contact toxicity and 4.07-7.02μl/L air in space fumigation. Except …

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Visual, Vibratory, And Olfactory Cues Affect Interactions Between The Red Spider Mite Tetranychus Evansi And Its Predator Phytoseiulus Longipes, Ginette Yèyinou Azandémè-Hounmalon, Baldwyn Torto, Komi Kouma Mokpokpo Fiaboe, Sevgan Subramanian, Serge Kreiter, Thibaud Martin Mar 2016

Visual, Vibratory, And Olfactory Cues Affect Interactions Between The Red Spider Mite Tetranychus Evansi And Its Predator Phytoseiulus Longipes, Ginette Yèyinou Azandémè-Hounmalon, Baldwyn Torto, Komi Kouma Mokpokpo Fiaboe, Sevgan Subramanian, Serge Kreiter, Thibaud Martin

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Phytoseiulus longipes Evans (Mesostigmata: Phytoseiidae) is an exotic predator widely used in biological control programs for the red spider mite Tetranychus evansi Baker & Pritchard (Acari: Tetranychidae) in East Africa. However, little is known about the cues mediating this prey/predator interaction. Here, we performed behavioral assays to test the involvement of visual, vibratory, and olfactory cues using a combination of dead/living insects enclosed in either perforated or non-perforated transparent/opaque capsules. We monitored insect responses with a video tracking system and analyzed the data with Ethovision software. Our results showed avoidance behavior of T. evansi in the presence of live P. …

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Impact Assessment Of Integrated Pest Management (Ipm) Strategy For Suppression Of Mango-Infesting Fruit Flies In Kenya, Beatrice W. Muriithi, Hippolyte D. Affognon, Gracious M. Diiro, Sarah W. Kingori, Chrysantus M. Tanga, Peterson W. Nderitu, Samira A. Mohamed, Sunday Ekesi Mar 2016

Impact Assessment Of Integrated Pest Management (Ipm) Strategy For Suppression Of Mango-Infesting Fruit Flies In Kenya, Beatrice W. Muriithi, Hippolyte D. Affognon, Gracious M. Diiro, Sarah W. Kingori, Chrysantus M. Tanga, Peterson W. Nderitu, Samira A. Mohamed, Sunday Ekesi

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We utilized two waves of data collected from a sample of mango farmers in Meru County in Kenya to evaluate the impact of Integrated Pest Management (IPM) strategy for controlling fruit flies in mango-production. We specifically explored the effect of five IPM practices including parasitoids (p) and Metarhizium anisopliae-based biopesticides (biop), orchard sanitation (os), spot spray of food bait (fb) and male annihilation technique (mat) on three outcome indicators: farmer pesticide expenditure, farm-level mango fruit yield losses and profit. We fitted difference-in-difference and household fixed effects regression models that account for unobserved heterogeneity across households. Our estimates differentiated the impact …

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Genome-Wide Comparative Analysis Of Chemosensory Gene Families In Five Tsetse Fly Species, Rosaline Macharia, Paul Mireji, Edwin Murungi, Grace Murilla, Alan Christoffels, Serap Aksoy, Daniel Masiga Feb 2016

Genome-Wide Comparative Analysis Of Chemosensory Gene Families In Five Tsetse Fly Species, Rosaline Macharia, Paul Mireji, Edwin Murungi, Grace Murilla, Alan Christoffels, Serap Aksoy, Daniel Masiga

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For decades, odour-baited traps have been used for control of tsetse flies (Diptera; Glossinidae), vectors of African trypanosomes. However, differential responses to known attractants have been reported in different Glossina species, hindering establishment of a universal vector control tool. Availability of full genome sequences of five Glossina species offers an opportunity to compare their chemosensory repertoire and enhance our understanding of their biology in relation to chemosensation. Here, we identified and annotated the major chemosensory gene families in Glossina. We identified a total of 118, 115, 124, and 123 chemosensory genes in Glossina austeni, G. brevipalpis, G. f. fuscipes, G. …

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Host Stage Preference And Performance Of The Aphid Parasitoid Diaeretiella Rapae (Hymenoptera: Braconidae) On Brevicoryne Brassicae And Lipaphis Pseudobrassicae (Hemiptera: Aphididae), Sylvia W.R. Khakasa, Samira A. Mohamed, Zipporah O. Lagat, Fathiya M. Khamis, Chrysantus M. Tanga Feb 2016

Host Stage Preference And Performance Of The Aphid Parasitoid Diaeretiella Rapae (Hymenoptera: Braconidae) On Brevicoryne Brassicae And Lipaphis Pseudobrassicae (Hemiptera: Aphididae), Sylvia W.R. Khakasa, Samira A. Mohamed, Zipporah O. Lagat, Fathiya M. Khamis, Chrysantus M. Tanga

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We assessed the host stage preference and performance of the aphid parasitoid Diaeretiella rapae (McIntosh) on two aphid species, Brevicoryne brassicae (L.) and Lipaphis pseudobrassicae (Davis). Although the parasitoid parasitized all nymphal instars of both aphid species, it showed a higher oviposition preference for 2nd (48.2 ± 7.74%) and 3rd (41.0 ± 7.82%) instars of L. pseudobrassicae, and for the 3rd (40.0 ± 4.59%) instar of B. brassicae. Across the host species, there was no significant difference in parasitoid preference between the 3rd and 4th instars, while 1st and 2nd instars of L. pseudobrassicae were significantly more preferred than their …

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Influence Of Temperature On Intra- And Interspecific Resource Utilization Within A Community Of Lepidopteran Maize Stemborers, Eric Siaw Ntiri, Paul Andre Calatayud, Johnnie Van Den Berg, Fritz Schulthess, Bruno Pierre Le Ru Feb 2016

Influence Of Temperature On Intra- And Interspecific Resource Utilization Within A Community Of Lepidopteran Maize Stemborers, Eric Siaw Ntiri, Paul Andre Calatayud, Johnnie Van Den Berg, Fritz Schulthess, Bruno Pierre Le Ru

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Competition or facilitation characterises intra- And interspecific interactions within communities of species that utilize the same resources. Temperature is an important factor influencing those interactions and eventual outcomes. The noctuid stemborers, Busseola fusca and Sesamia calamistis and the crambid Chilo partellus attack maize in sub-Saharan Africa. They often occur as a community of interacting species in the same field and plant at all elevations. The influence of temperature on the intra- And interspecific interactions among larvae of these species, was studied using potted maize plants exposed to varying temperatures in a greenhouse and artificial stems kept at different constant temperatures …

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Developing And Deploying Insect Resistant Maize Varieties To Reduce Pre-And Post-Harvest Food Losses In Africa, Tadele Tefera, Stephen Mugo, Yoseph Beyene Feb 2016

Developing And Deploying Insect Resistant Maize Varieties To Reduce Pre-And Post-Harvest Food Losses In Africa, Tadele Tefera, Stephen Mugo, Yoseph Beyene

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Maize grain yield in Africa is low, 1.5 t ha−1 compared to the global average of 4.9 t ha−1. Maize production in Africa is constrained by various abiotic (drought, soil fertility) and biotic factors (insect pests, weeds and diseases). Stem borers and postharvest insect pests play considerable roles in reducing maize yield through damaging the leaves, stems, ears, and kernels. Stem borers can cause 10–15 % yield losses while the postharvest insect pests, particularly, the larger grain borer and maize weevil, can cause 14–36 % grain losses. The use of chemical insecticides has been recommended; however, in addition to health …

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Identification Of Aphid (Hemiptera: Aphididae) Species Of Economic Importance In Kenya Using Dna Barcodes And Pcr-Rflp-Based Approach, G. Kinyanjui, F. M. Khamis, S. Mohamed, L. O. Ombura, M. Warigia, S. Ekesi Feb 2016

Identification Of Aphid (Hemiptera: Aphididae) Species Of Economic Importance In Kenya Using Dna Barcodes And Pcr-Rflp-Based Approach, G. Kinyanjui, F. M. Khamis, S. Mohamed, L. O. Ombura, M. Warigia, S. Ekesi

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Aphids are among pests of economic importance throughout the world. Together with transmitting plant viruses, aphids are capable of inflicting severe crop production losses. They also excrete honeydew that favours the growth of sooty mold which reduces the quality of vegetables and fruits and hence their market values. Rapid and accurate identification of aphids to the species level is a critical component in effective pest management and plant quarantine systems. Even though morphological taxonomy has made a tremendous impact on species-level identifications, polymorphism, morphological plasticity and immature stages are among the many challenges to accurate identification. In addition, their small …

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Enhancement Of Synchronization In Inter-Intra-Connected Neuronal Networks, F. M. Moukam Kakmeni, V. M. Nguemaha Jan 2016

Enhancement Of Synchronization In Inter-Intra-Connected Neuronal Networks, F. M. Moukam Kakmeni, V. M. Nguemaha

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We study the enhancement of neural synchrony in a network of electrically coupled Hindmarsh Rose (HR) neurons. The behavior of the network under control by an external environment modeled by the Fitzhugh Nagumo (FN) is analyzed. Biologically, such a control system could mimic the modification of normal neuronal dynamics due to drugs or other chemical substances. We show that the environment could have as effect the suppression of chaos, enhancement of synchrony and favor interesting properties such as sub-threshold membrane oscillations, and oscillation death for relatively strong local coupling. Interestingly, we find that the electrical coupling between each two coupled …

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Active Aggregation Among Sexes In Bean Flower Thrips (Megalurothrips Sjostedti) On Cowpea (Vigna Unguiculata), Saliou Niassy, Sunday Ekesi, Nguya K. Maniania, Benedict Orindi, Gerald B. Moritz, Willem J. De Kogel, Sevgan Subramanian Jan 2016

Active Aggregation Among Sexes In Bean Flower Thrips (Megalurothrips Sjostedti) On Cowpea (Vigna Unguiculata), Saliou Niassy, Sunday Ekesi, Nguya K. Maniania, Benedict Orindi, Gerald B. Moritz, Willem J. De Kogel, Sevgan Subramanian

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Male sexual aggregations are a common territorial, mating-related or resource-based, behaviour observed in diverse organisms, including insects such as thrips. The influence of factors such as plant substrate, time of day, and geographic location on aggregation of thrips is uncertain, therefore we monitored the dispersion of male and female bean flower thrips (BFT), Megalurothrips sjostedti (Trybom) (Thysanoptera: Thripidae), on cowpea, Vigna unguiculata (L.) Walp. (Fabaceae), over three cowpea growth stages and across three cowpea-growing areas of Kenya. Our results indicated that for all the crop growth stages, the density of BFTs varied over the time of day, with higher densities …

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Rapid And High Throughput Molecular Identification Of Diverse Mosquito Species By High Resolution Melting Analysis., Yvonne Ukamaka Ajamma, Enock Mararo, David Omondi, Thomas Onchuru, Anne W.T. Muigai, Daniel Masiga, Jandouwe Villinger Jan 2016

Rapid And High Throughput Molecular Identification Of Diverse Mosquito Species By High Resolution Melting Analysis., Yvonne Ukamaka Ajamma, Enock Mararo, David Omondi, Thomas Onchuru, Anne W.T. Muigai, Daniel Masiga, Jandouwe Villinger

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Mosquitoes are a diverse group of invertebrates, with members that are among the most important vectors of diseases. The correct identification of mosquitoes is paramount to the control of the diseases that they transmit. However, morphological techniques depend on the quality of the specimen and often unavailable taxonomic expertise, which may still not be able to distinguish mosquitoes among species complexes (sibling and cryptic species). High resolution melting (HRM) analyses, a closed-tube, post-polymerase chain reaction (PCR) method used to identify variations in nucleic acid sequences, has been used to differentiate species within the Anopheles gambiae and Culex pipiens complexes. We …

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Role Of Microsatellite Markers In Molecular Population Genetics Of Fruit Flies With Emphasis On The Bactrocera Dorsalis Invasion Of Africa, Fathiya M. Khamis, Anna R. Malacrida Jan 2016

Role Of Microsatellite Markers In Molecular Population Genetics Of Fruit Flies With Emphasis On The Bactrocera Dorsalis Invasion Of Africa, Fathiya M. Khamis, Anna R. Malacrida

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Microsatellites, also referred to as short tandem repeats (STRs) or simple sequence repeats (SSRs) are short sequences of tandem repeats of 1-6 bp in length in clusters of less than 150 bp flanked by sections of non-repetitive unique sequences that are scattered throughout the nuclear genome. These markers are co-dominant and hypervariable, revealing many alleles per locus; they are inherited in Mendelian fashion making them useful for detecting genetic variability within species. Once isolated and characterized, microsatellites can also be used in closely related taxa. Microsatellites can be amplified, even from highly degraded DNA, and are very simple to score. …

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Maize Landraces Are Less Affected By Striga Hermonthica Relative To Hybrids In Western Kenya, Charles A.O. Midega, John Pickett, Antony Hooper, Jimmy Pittchar, Zeyaur R. Khan Jan 2016

Maize Landraces Are Less Affected By Striga Hermonthica Relative To Hybrids In Western Kenya, Charles A.O. Midega, John Pickett, Antony Hooper, Jimmy Pittchar, Zeyaur R. Khan

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Production of maize in western Kenya is severely constrained by the parasitic weed striga. Although productivity of maize can be improved through adoption of improved varieties, adoption of such varieties remains low in the region, as the majority of smallholder farmers still grow unimproved open-pollinated varieties (landraces). The performance of two improved hybrid varieties was evaluated against six landraces in striga-infested soils in western Kenya. The varieties were planted in plots under natural striga infestation and were supplemented with pot experiments under artificial infestation. Striga emergence was lower in landraces than in the hybrid varieties in both field and pot …

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Spatial Separation Of Semiochemical Lurem-Tr And Entomopathogenic Fungi To Enhance Their Compatibility And Infectivity In An Autoinoculation System For Thrips Management, David K. Mfuti, Sevgan Subramanian, Rob Whm Van Tol, Gerrie L. Wiegers, Willem J. De Kogel, Saliou Niassy, Hannalene Du Plessis, Sunday Ekesi, Nguya K. Maniania Jan 2016

Spatial Separation Of Semiochemical Lurem-Tr And Entomopathogenic Fungi To Enhance Their Compatibility And Infectivity In An Autoinoculation System For Thrips Management, David K. Mfuti, Sevgan Subramanian, Rob Whm Van Tol, Gerrie L. Wiegers, Willem J. De Kogel, Saliou Niassy, Hannalene Du Plessis, Sunday Ekesi, Nguya K. Maniania

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BACKGROUND: The effect of spatial separation of the semiochemical Lurem-TR, which has been found to inhibit conidia of entomopathogenic fungi when put together, on the persistence of conidia of Metarhizium brunneum and M. anisopliae was evaluated in the greenhouse and field in order to develop an autodissemination strategy for the management of Megalurothrips sjostedti on cowpea crop. Influence of spatial separation of the semiochemical on thrips attraction and conidial acquisition by thrips from the autoinoculation device was also investigated in the field. RESULTS: Persistence of conidia of M. brunneum and M. anisopliae increased with distance of separation of Lurem-TR. Direct …

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Some Key Elements On Entomophagy In Africa: Culture, Gender And Belief, S. Niassy, H. D. Affognon, K. K.M. Fiaboe, K. S. Akutse, C. M. Tanga, S. Ekesi Jan 2016

Some Key Elements On Entomophagy In Africa: Culture, Gender And Belief, S. Niassy, H. D. Affognon, K. K.M. Fiaboe, K. S. Akutse, C. M. Tanga, S. Ekesi

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Edible insects are a natural renewable food resource and, within the context of food security could be one solution for Africa. Although, entomophagy is still being practiced in Africa, there is a degree of rejection in certain milieu due to negative images associated with insects and poor awareness efforts. In order to understand the key elements that govern entomophagy in Africa, we conducted an online survey on edible insects in African countries and documented the importance of insects, cultures and believes associated to their use. We eventually looked at gender participation in entomophagy. Study showed that insect consumption can be …

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Fruit Fly Species Composition, Distribution And Host Plants With Emphasis On Mango- Infesting Species, Ivan Rwomushana, Chrysantus M. Tanga Jan 2016

Fruit Fly Species Composition, Distribution And Host Plants With Emphasis On Mango- Infesting Species, Ivan Rwomushana, Chrysantus M. Tanga

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Mango is the most widely cultivated fruit tree in tropical and sub-tropical Africa. However, the sustainability of this lucrative business is threatened by infestations of fruit flies (Diptera: Tephritidae) that annually inflict heavy economic losses on the industry. The nutritional quality of different fruit species can influence the survival and fecundity of adult fruit flies. This host-insect interaction determines the species composition, distribution and abundance of the major frugivorous tephritids. The economic impact of fruit fly pest species includes direct yield losses and the loss of export markets due to quarantine restrictions implemented to prevent the entry and establishment of …

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Integrated Management Of Fruit Flies-Case Studies From Uganda, Brian E. Isabirye, Caroline K. Nankinga, Alex Mayamba, Anne M. Akol, Ivan Rwomushana Jan 2016

Integrated Management Of Fruit Flies-Case Studies From Uganda, Brian E. Isabirye, Caroline K. Nankinga, Alex Mayamba, Anne M. Akol, Ivan Rwomushana

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Fruit flies (Diptera: Tephritidae) pose a threat to commercialisation of the horticulture industry in Uganda. They impair the quality and quantity of fruits produced, and limit access to lucrative regional and global markets. Here we explore past and present efforts, and future plans for research and management, of fruit flies in Uganda. Early research geared towards collection and identification of fruit flies recognised the pest status of many species and highlighted the need for establishing sustainable management strategies. Subsequently large-scale research initiatives have substantially increased knowledge on the biology and ecology of fruit flies in Uganda. Based on these studies, …

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Wildebeest-Associated Malignant Catarrhal Fever: Perspectives For Integrated Control Of A Lymphoproliferative Disease Of Cattle In Sub-Saharan Africa, Lillian Wambua, Peninah Nduku Wambua, Allan Maurice Ramogo, Domnic Mijele, Moses Yongo Otiende Jan 2016

Wildebeest-Associated Malignant Catarrhal Fever: Perspectives For Integrated Control Of A Lymphoproliferative Disease Of Cattle In Sub-Saharan Africa, Lillian Wambua, Peninah Nduku Wambua, Allan Maurice Ramogo, Domnic Mijele, Moses Yongo Otiende

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Wildebeest-associated malignant catarrhal fever (WA-MCF), an acute lymphoproliferative disease of cattle caused by alcelaphine herpesvirus 1 (AlHV-1), remains a significant constraint to cattle production in nomadic pastoralist systems in eastern and southern Africa. The transmission of WA-MCF is dependent on the presence of the wildlife reservoir, i.e. wildebeest, belonging to the species Connochaetes taurinus and Connochaetes gnou; hence, the distribution of WA-MCF is largely restricted to Kenya, Tanzania and the Republic of South Africa, where wildebeest are present. WA-MCF is analogous to sheep-associated MCF (SA-MCF) in many aspects, with the latter having sheep as its reservoir host and a more …

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Determination Of Pesticide Residues In Honey: A Preliminary Study From Two Of Africa’S Largest Honey Producers, Janet Irungu, Suresh Raina, Baldwyn Torto Jan 2016

Determination Of Pesticide Residues In Honey: A Preliminary Study From Two Of Africa’S Largest Honey Producers, Janet Irungu, Suresh Raina, Baldwyn Torto

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Background: The presence of pollutants in honey can influence honey bee colony performance and devalue its use for human consumption. Using liquid chromatography tandem mass spectrometry (LC-MS/MS), various clean-up methods were evaluated for efficient determination of multiclass pesticide contaminants in honey. The selected clean-up method was optimized and validated and then applied to perform a preliminary study of commercial honey samples from Africa. Results: The most efficient method was primary-secondary amine (PSA) sorbent which was significantly different from the others (P <0.05; average recovery ~94 %) and was applied to analyze 96 pesticide residues in 28 retail honey samples from Kenya and Ethiopia. From our preliminary data, a total of 17 pesticide residues were detected at ~10-fold below maximum residue limit (MRL) established for food products except for malathion which was detected at almost 2-fold above its acceptable MRL. Conclusions: A highly efficient approach for determining pesticide residues in honey with good recoveries was developed. All residue contaminants were detected at levels well below their acceptable MRLs except malathion suggesting that the retail honey analyzed is safe for human consumption. Although PSA clean-up method was selected as the most efficient for cleaning honey samples, omitting the clean-up step was the most economical approach with potential applicability in the food industry.

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Fruit Fly Nutrition, Rearing And Quality Control, Samira A. Mohamed, Fathiya M. Khamis, Chrysantus M. Tanga Jan 2016

Fruit Fly Nutrition, Rearing And Quality Control, Samira A. Mohamed, Fathiya M. Khamis, Chrysantus M. Tanga

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Tephritid fruit flies are recognized worldwide as an important threat to the horticultural industry. Most of the species belonging to this group are highly polyphagous attacking several important fruits and vegetables. They cause direct damage through larval feeding and indirect losses are associated with quarantine restrictions. The increasing awareness of the damage caused by these fruit flies to the horticultural industry has created a demand for the development of control measures based on integrated pest management (IPM) strategies and the sterile insect technique (SIT). However, success of the majority of these control methods largely depends on the ability to establish …

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Fruit Fly Species Composition, Distribution And Host Plants With Emphasis On Vegetable-Infesting Species, Chrysantus M. Tanga, Ivan Rwomushana Jan 2016

Fruit Fly Species Composition, Distribution And Host Plants With Emphasis On Vegetable-Infesting Species, Chrysantus M. Tanga, Ivan Rwomushana

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Vegetable crops hold a key position in smallholder agricultural production systems in Africa due to the number of farmers involved, income generation, employment opportunities, and enhancement of food and nutritional security. In many developed countries, demand for vegetables continues to grow due to increased awareness of the nutritional benefits, thereby stimulating increased domestic production and also imports from Africa. However, many pests threaten the productivity of the vegetable sector. Key amongst these are tephritid fruit flies that inflict both direct and indirect losses; alien invasive species are often responsible for severe ecological and economic impacts. The highly invasive and polyphagous …

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Mosquito Host Choices On Livestock Amplifiers Of Rift Valley Fever Virus In Kenya, David P. Tchouassi, Robinson O.K. Okiro, Rosemary Sang, Lee W. Cohnstaedt, David Scott Mcvey, Baldwyn Torto Jan 2016

Mosquito Host Choices On Livestock Amplifiers Of Rift Valley Fever Virus In Kenya, David P. Tchouassi, Robinson O.K. Okiro, Rosemary Sang, Lee W. Cohnstaedt, David Scott Mcvey, Baldwyn Torto

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Background: Animal hosts may vary in their attraction and acceptability as components of the host location process for assessing preference, and biting rates of vectors and risk of exposure to pathogens. However, these parameters remain poorly understood for mosquito vectors of the Rift Valley fever (RVF), an arboviral disease, and for a community of mosquitoes. Methods: Using three known livestock amplifiers of RVF virus including sheep, goat and cattle as bait in enclosure traps, we investigated the host-feeding patterns for a community of mosquitoes in Naivasha, an endemic area of Rift Valley fever (RVF), in a longitudinal study for six …

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Plant Resting Site Preferences And Parity Rates Among The Vectors Of Rift Valley Fever In Northeastern Kenya, Samwel O. Arum, Christopher W. Weldon, Benedict Orindi, Caroline Tigoi, Francis Musili, Tobias Landmann, David P. Tchouassi, Hippolyte D. Affognon, Rosemary Sang Jan 2016

Plant Resting Site Preferences And Parity Rates Among The Vectors Of Rift Valley Fever In Northeastern Kenya, Samwel O. Arum, Christopher W. Weldon, Benedict Orindi, Caroline Tigoi, Francis Musili, Tobias Landmann, David P. Tchouassi, Hippolyte D. Affognon, Rosemary Sang

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Background: Mosquito lifespan can influence the circulation of disease causing pathogens because it affects the time available for infection and transmission. The life-cycle of mosquitoes is determined by intrinsic and environmental factors, which can include the availability of hosts and suitable resting environments that shelter mosquitoes from extreme temperature and desiccating conditions. This study determined the parity rates (an indirect measure of survival) and plant resting preference of vectors of Rift Valley fever (RVF) in northeastern Kenya. Methods: Resting mosquitoes were trapped during the rainy and the dry season using a Prokopack aspirator from vegetation, whereas general adult populations were …

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Bivalent Carbamates As Novel Control Agents Of The Malaria Mosquito, Anopheles Gambiae, James M. Mutunga, Qiao Hong Chen, Dawn M. Wong, Polo C.H. Lam, Jianyong Li, Maxim M. Totrov, Aaron D. Gross, Paul R. Carlier, Jeffrey R. Bloomquist Jan 2016

Bivalent Carbamates As Novel Control Agents Of The Malaria Mosquito, Anopheles Gambiae, James M. Mutunga, Qiao Hong Chen, Dawn M. Wong, Polo C.H. Lam, Jianyong Li, Maxim M. Totrov, Aaron D. Gross, Paul R. Carlier, Jeffrey R. Bloomquist

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Widespread pyrethroid resistance has caused an urgent need to develop new insecticides for control of the malaria mosquito, Anopheles gambiae. Insecticide discovery efforts were directed towards the construction of bivalent inhibitors that occupy both the peripheral and catalytic sites of the mosquito acetylcholinesterase (AChE). It was hypothesized that this approach would yield a selective, high potency inhibitor that would also circumvent known catalytic site mutations (e.g. G119S) causing target site resistance. Accordingly, a series of bivalent phthalimide-pyrazole carbamates were prepared having an alkyl chain linker of varying length, along with other modifications. The most active compound was (1-(3-(1,3-dioxoisoindolin-2-yl)propyl)-1H-pyrazol-4-yl methylcarbamate, 8a), …

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Mitochondrial Coding Genome Analysis Of Tropical Root-Knot Nematodes (Meloidogyne) Supports Haplotype Based Diagnostics And Reveals Evidence Of Recent Reticulate Evolution, Toon Janssen, Gerrit Karssen, Myrtle Verhaeven, Danny Coyne, Wim Bert Jan 2016

Mitochondrial Coding Genome Analysis Of Tropical Root-Knot Nematodes (Meloidogyne) Supports Haplotype Based Diagnostics And Reveals Evidence Of Recent Reticulate Evolution, Toon Janssen, Gerrit Karssen, Myrtle Verhaeven, Danny Coyne, Wim Bert

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The polyphagous parthenogenetic root-knot nematodes of the genus Meloidogyne are considered to be the most significant nematode pest in sub-tropical and tropical agriculture. Despite the crucial need for correct diagnosis, identification of these pathogens remains problematic. The traditionally used diagnostic strategies, including morphometrics, host-range tests, biochemical and molecular techniques, now appear to be unreliable due to the recently-suggested hybrid origin of root-knot nematodes. In order to determine a suitable barcode region for these pathogens nine quickly-evolving mitochondrial coding genes were screened. Resulting haplotype networks revealed closely related lineages indicating a recent speciation, an anthropogenic-aided distribution through agricultural practices, and evidence …

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Impact Of Reduced Tillage And Crop Residue Management On Soil Properties And Crop Yields In A Long-Term Trial In Western Kenya, Jeremiah M. Okeyo, Jay Norton, Saidou Koala, Boaz Waswa, Job Kihara, Andre Bationo Jan 2016

Impact Of Reduced Tillage And Crop Residue Management On Soil Properties And Crop Yields In A Long-Term Trial In Western Kenya, Jeremiah M. Okeyo, Jay Norton, Saidou Koala, Boaz Waswa, Job Kihara, Andre Bationo

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Sustainable farming practices are required to address the persistent problems of land degradation and declining crop productivity in Sub-Saharan Africa. Approaches such as reducing tillage and retaining crop residues as mulch are potential entry points for smallholder farmers to move towards sustainability. In this study, we assessed the impact of reduced tillage (RT) compared with conventional tillage (CT), each combined with crop residue reapplication, on soil quality indicators and crop yields under an 8-year trial in western Kenya. Our results indicate that RT combined with crop residue reapplication enhanced soil physical quality through increased macroaggregate (>2000μm) proportions and mean …

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Megastigmus Seed Chalcids (Hymenoptera, Torymidae) Radiated Much More On Angiosperms Than Previously Considered. I- Description Of 8 New Species From Kenya, With A Key To The Females Of Eastern And Southern Africa, Alain Roques, Robert S. Copeland, Laurent Soldati, Olivier Denux, Marie Anne Auger-Rozenberg Jan 2016

Megastigmus Seed Chalcids (Hymenoptera, Torymidae) Radiated Much More On Angiosperms Than Previously Considered. I- Description Of 8 New Species From Kenya, With A Key To The Females Of Eastern And Southern Africa, Alain Roques, Robert S. Copeland, Laurent Soldati, Olivier Denux, Marie Anne Auger-Rozenberg

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A survey of seed chalcids from woody plants in Kenya revealed 12 species belonging to the genus Megastigmus Dalman, 1820, and has increased to 16 the number of Megastigmus species presently recorded from the Afrotropical Region, of which at least 13 are seed feeders. A key to female Megastigmus of the Afrotropical Region is provided. Eight new species are described from morphological evidence: M. lanneae Roques & Copeland, M. laventhali Roques & Copeland, M. ozoroae Roques & Copeland, and M. smithi Roques & Copeland in seeds of species of the family Anacardiaceae, M. copelandi Roques & Copeland and M. grewianae …

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Eco-Friendly Nets To Improve Vegetable Production And Quality In Sub-Saharan Africa, T. Martin, S. Simon, L. Parrot, F. Assogba Komlan, F. Vidogbena, A. Adegbidi, V. Baird, M. Saidi, M. Kasina, L. A. Wasilwa, S. Subramanian, M. Ngouajio Dec 2015

Eco-Friendly Nets To Improve Vegetable Production And Quality In Sub-Saharan Africa, T. Martin, S. Simon, L. Parrot, F. Assogba Komlan, F. Vidogbena, A. Adegbidi, V. Baird, M. Saidi, M. Kasina, L. A. Wasilwa, S. Subramanian, M. Ngouajio

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Continuous coverage of vegetables with nets under different climate conditions in Benin and Kenya proved effective in protecting vegetable nurseries and main fields against key lepidopteran and dipteran pests. However, netting did not effectively protect the vegetables against small insects such as aphids and whiteflies, although a visual barrier could delay outbreaks. Hence, opening the nets during the day could be an alternative option to conserve the natural enemies for small insects. Moreover, the efficacy of the visual barrier may be complemented by a repellent compound impregnated in the net. The small-holder growers adopting the nets in Benin and Kenya …

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Antagonistic Interactions Between The Africanweaver Ant Oecophylla Longinoda And The Parasitoid Anagyrus Pseudococci Potentially Limits Suppression Of The Invasive Mealybug Rastrococcus Iceryoides, Chrysantus M. Tanga, Sunday Ekesi, Prem Govender, Peterson W. Nderitu, Samira A. Mohamed Dec 2015

Antagonistic Interactions Between The Africanweaver Ant Oecophylla Longinoda And The Parasitoid Anagyrus Pseudococci Potentially Limits Suppression Of The Invasive Mealybug Rastrococcus Iceryoides, Chrysantus M. Tanga, Sunday Ekesi, Prem Govender, Peterson W. Nderitu, Samira A. Mohamed

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The ant Oecophylla longinoda Latreille forms a trophobiotic relationship with the invasive mealybug Rastrococus iceryoides Green and promotes the latter’s infestations to unacceptable levels in the presence of their natural enemies. In this regard, the antagonistic interactions between the ant and the parasitoid Anagyrus pseudococci Girault were assessed under laboratory conditions. The percentage of parasitism of R. iceryoides by A. pseudococci was significantly higher on “ant-excluded” treatments (86.6% ± 1.27%) compared to “ant-tended” treatments (51.4% ± 4.13%). The low female-biased sex-ratio observed in the “ant-tended” treatment can be attributed to ants’ interference during the oviposition phase, which disrupted parasitoids’ ability …

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Cost: Benefit Analysis Of Insect Net Use In Cabbage In Real Farming Conditions Among Smallholder Farmers In Benin, Faustin Vidogbéna, Anselme Adégbidi, Françoise Assogba-Komlan, Thibaud Martin, Mathieu Ngouajio, Serge Simon, Rigobert Tossou, Laurent Parrot Dec 2015

Cost: Benefit Analysis Of Insect Net Use In Cabbage In Real Farming Conditions Among Smallholder Farmers In Benin, Faustin Vidogbéna, Anselme Adégbidi, Françoise Assogba-Komlan, Thibaud Martin, Mathieu Ngouajio, Serge Simon, Rigobert Tossou, Laurent Parrot

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Insect net use provides a physical exclusion of pests as well as a microclimate change, thus increasing soil humidity, vegetable quality and yields in tropical conditions. This paper presents the findings of a cost:benefit analysis of this technology in real farming conditions compared to current insecticide practices. The surveys were conducted in Benin for cabbage production (. Brassica oleracea L.) during two production cycles. There were almost no significant differences in costs between unnetted and netted cabbage for the two production cycles. The only factors that varied were farm gate prices, the number of cabbages marketed and their size. Improved …

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