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Full-Text Articles in Life Sciences

Egg-Laying Decisions Based On Olfactory Cues Enhance Offspring Fitness In Stomoxys Calcitrans L. (Diptera: Muscidae), Steve B.S. Baleba, Baldwyn Torto, Daniel Masiga, Christopher W. Weldon, Merid N. Getahun Dec 2019

Egg-Laying Decisions Based On Olfactory Cues Enhance Offspring Fitness In Stomoxys Calcitrans L. (Diptera: Muscidae), Steve B.S. Baleba, Baldwyn Torto, Daniel Masiga, Christopher W. Weldon, Merid N. Getahun

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Selection of oviposition substrate is critical in holometabolous insects. Female stable flies, Stomoxys calcitrans, locate and select vertebrate herbivore dung in which they lay their eggs. However, the preference for vertebrate herbivore dung by S. calcitrans females, its fitness consequences for offspring, and the semiochemicals used to locate and select oviposition substrates remain unclear. Using oviposition choice tests and life table bioassays we found that gravid female S. calcitrans prefer to oviposit on donkey and sheep dung, which also improves the performance of their offspring. GC-MS analysis followed by random forest classification identified β-citronellene and carvone as the most important …

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Molasses Grass Induces Direct And Indirect Defense Responses In Neighbouring Maize Plants, Tigist A. Tolosa, Amanuel Tamiru, Charles A.O. Midega, Johnnie Van Den Berg, Michael A. Birkett, Christine M. Woodcock, Toby J.A. Bruce, Segenet Kelemu, John A. Pickett, Zeyaur R. Khan Dec 2019

Molasses Grass Induces Direct And Indirect Defense Responses In Neighbouring Maize Plants, Tigist A. Tolosa, Amanuel Tamiru, Charles A.O. Midega, Johnnie Van Den Berg, Michael A. Birkett, Christine M. Woodcock, Toby J.A. Bruce, Segenet Kelemu, John A. Pickett, Zeyaur R. Khan

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Plants have evolved intricate defence strategies against herbivore attack which can include activation of defence in response to stress-related volatile organic compounds (VOCs) emitted by neighbouring plants. VOCs released by intact molasses grass (Melinis minutiflora), have been shown to repel stemborer, Chilo partellus (Swinhoe), from maize and enhance parasitism by Cotesia sesamiae (Cameron). In this study, we tested whether the molasses grass VOCs have a role in plant-plant communication by exposing different maize cultivars to molasses grass for a 3-week induction period and then observing insect responses to the exposed plants. In bioassays, C. partellus preferred non-exposed maize landrace plants …

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Variability Of Soybean Response To Rhizobia Inoculant, Vermicompost, And A Legume-Specific Fertilizer Blend In Siaya County Of Kenya, Catherine Mathenge, Moses Thuita, Cargele Masso, Joseph Gweyi-Onyango, Bernard Vanlauwe Nov 2019

Variability Of Soybean Response To Rhizobia Inoculant, Vermicompost, And A Legume-Specific Fertilizer Blend In Siaya County Of Kenya, Catherine Mathenge, Moses Thuita, Cargele Masso, Joseph Gweyi-Onyango, Bernard Vanlauwe

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Rhizobia inoculation can increase soybean yield, but its performance is influenced by among others soybean genotype, rhizobia strains, environment, and crop management. The objective of the study was to assess soybean response to rhizobia inoculation when grown in soils amended with urea or vermicompost to improve nitrogen levels. Two greenhouse experiments and one field trial at two sites were carried out. The first greenhouse experiment included soils from sixty locations, sampled from smallholder farms in Western Kenya. The second greenhouse experiment consisted of one soil selected among soils used in the first experiment where inoculation response was poor. The soil …

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Distribution And Incidence Of The Oil Palm Weevil Rhynchophorus Phoenicis (Fabricius, 1801) (Coleoptera: Curculionidae) In Selected Agro-Ecological Zones Of Uganda, J. Baguma, M. Otema, G. Ddamulira, R. Naluyimba, J. P. Egonyu Oct 2019

Distribution And Incidence Of The Oil Palm Weevil Rhynchophorus Phoenicis (Fabricius, 1801) (Coleoptera: Curculionidae) In Selected Agro-Ecological Zones Of Uganda, J. Baguma, M. Otema, G. Ddamulira, R. Naluyimba, J. P. Egonyu

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The genus Rhynchophorus (Herbst 1795) (Coleoptera: Curculionidae) is a key pest of palms worldwide, but information on Rhynchophorus spp. attacking the oil palm, Elaeis guineensis Jaquin in Uganda is outdated. This study was carried out to establish the diversity, distribution and incidence of Rhynchophorus spp. on E. guineensis at three production set-ups namely large-scale plantations, adaptive trials and small-scale farms in three (Lake Victoria Crescent, Lake Albert Crescent and Western Highlands) agro-ecological zones in Uganda; and to establish the effect of vicinity to natural vegetation on incidence of the pest. Two surveys were conducted in 2018 during the dry and …

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Experienced Males Recognise And Avoid Mating With Non-Virgin Females In The Western Flower Thrips, Adeyemi O. Akinyemi, William D.J. Kirk Oct 2019

Experienced Males Recognise And Avoid Mating With Non-Virgin Females In The Western Flower Thrips, Adeyemi O. Akinyemi, William D.J. Kirk

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The western flower thrips Frankliniella occidentalis (Thysanoptera: Thripidae) is a major insect pest on a wide range of crops throughout the world. There are several unexplained aspects of the mating behaviour, particularly in relation to male-male competition and mate choice. The objectives of the study were to test whether males can detect the mating status of females and whether males avoid mating with previously mated females. Experiments involved either 'experienced' adults taken from a laboratory culture, which had been exposed to high densities of thrips, or virgin adults reared individually. Experienced males mated readily with virgin females, but avoided mating …

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Effect Of Dietary Replacement Of Fishmeal By Insect Meal On Growth Performance, Blood Profiles And Economics Of Growing Pigs In Kenya, Shaphan Y. Chia, Chrysantus M. Tanga, Isaac M. Osuga, Alphonce O. Alaru, David M. Mwangi, Macdonald Githinji, Sevgan Subramanian, Komi K.M. Fiaboe, Sunday Ekesi, Joop J.A. Van Loon, Marcel Dicke Oct 2019

Effect Of Dietary Replacement Of Fishmeal By Insect Meal On Growth Performance, Blood Profiles And Economics Of Growing Pigs In Kenya, Shaphan Y. Chia, Chrysantus M. Tanga, Isaac M. Osuga, Alphonce O. Alaru, David M. Mwangi, Macdonald Githinji, Sevgan Subramanian, Komi K.M. Fiaboe, Sunday Ekesi, Joop J.A. Van Loon, Marcel Dicke

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Pig production is one of the fastest growing livestock sectors. Development of this sector is hampered by rapidly increasing costs of fishmeal (FM), which is a common protein source in animal feeds. Here, we explored the potential of substituting FM with black soldier fly larval meal (BSFLM) on growth and blood parameters of pigs as well as economic aspects. At weaning, 40 hybrid pigs, i.e., crossbreeds of purebred Large White and Landrace were randomly assigned to five iso-nitrogenous and iso-energetic dietary treatments: Control (0% BSFLM and 100% FM (T0)), and FM replaced at 25% (T25), 50% (T50), 75% (T75) and …

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Cadmium Tolerance Pathway In Anopheles Gambiae Senso Stricto, Martin K. Rono, Catherine N. Muturi, Richard Ochieng, Ramadhan Mwakubabanya, Francis N. Wachira, Joseph Mwangangi, Sam Kinyanjui, James Njunge, Paul O. Mireji Oct 2019

Cadmium Tolerance Pathway In Anopheles Gambiae Senso Stricto, Martin K. Rono, Catherine N. Muturi, Richard Ochieng, Ramadhan Mwakubabanya, Francis N. Wachira, Joseph Mwangangi, Sam Kinyanjui, James Njunge, Paul O. Mireji

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Cadmium is one of the widely used heavy metals (HM) in commercial and industrial products and contributes to environmental contamination in an urban setting. In our previous studies, we established that An. gambiae sensu stricto, a vector of malaria, had adapted to HM pollutants in nature despite their proclivity for unpolluted aquatic habitats. We further demonstrated that heavy metal tolerance adaptation process impacts a biological cost to the fitness of the mosquito and potentially involves the induction of specific HM-responsive transcripts and proteins. Here we interrogated differential proteomic profiles of the cadmium tolerant vs. naïve strains of An. gambiae to …

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Effect Of Crop Diversification And Mulching On Termite Damage To Maize In Western Ethiopia, Girma Demissie, Esayas Mendesil, Debela Diro, Tadele Tefera Oct 2019

Effect Of Crop Diversification And Mulching On Termite Damage To Maize In Western Ethiopia, Girma Demissie, Esayas Mendesil, Debela Diro, Tadele Tefera

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Termites are major biotic factors that contribute to crop damage and yield losses to maize (Zea mays L.) in western Ethiopia. This study evaluated mulching maize stover, intercropping maize with soybean (Glycine max (L.) Merr.) and desmodium (Desmodium intortum (Mill.) Urb.), and integration of mulching and intercropping for their effectiveness in reducing damage of Microtermes spp mainly Microtermes vadschaggae Sjostedt and Microtermes adschaggae (Sjosted) to maize. Five termite management treatments and a control (sole maize) were arranged in a randomized complete block design with three replicates on 2 farm sites in 2016 and 7 sites in 2017 cropping seasons in …

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Comparative Genomic Analysis Of Six Glossina Genomes, Vectors Of African Trypanosomes, Geoffrey M. Attardo, Adly M.M. Abd-Alla, Alvaro Acosta-Serrano, James E. Allen, Rosemary Bateta, Joshua B. Benoit, Kostas Bourtzis, Jelle Caers, Guy Caljon, Mikkel B. Christensen, David W. Farrow, Markus Friedrich, Aurélie Hua-Van, Emily C. Jennings, Denis M. Larkin, Daniel Lawson, Michael J. Lehane, Vasileios P. Lenis, Ernesto Lowy-Gallego, Rosaline W. Macharia, Anna R. Malacrida, Heather G. Marco, Daniel Masiga, Gareth L. Maslen, Irina Matetovici, Richard P. Meisel, Irene Meki, Veronika Michalkova Sep 2019

Comparative Genomic Analysis Of Six Glossina Genomes, Vectors Of African Trypanosomes, Geoffrey M. Attardo, Adly M.M. Abd-Alla, Alvaro Acosta-Serrano, James E. Allen, Rosemary Bateta, Joshua B. Benoit, Kostas Bourtzis, Jelle Caers, Guy Caljon, Mikkel B. Christensen, David W. Farrow, Markus Friedrich, Aurélie Hua-Van, Emily C. Jennings, Denis M. Larkin, Daniel Lawson, Michael J. Lehane, Vasileios P. Lenis, Ernesto Lowy-Gallego, Rosaline W. Macharia, Anna R. Malacrida, Heather G. Marco, Daniel Masiga, Gareth L. Maslen, Irina Matetovici, Richard P. Meisel, Irene Meki, Veronika Michalkova

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Background: Tsetse flies (Glossina sp.) are the vectors of human and animal trypanosomiasis throughout sub-Saharan Africa. Tsetse flies are distinguished from other Diptera by unique adaptations, including lactation and the birthing of live young (obligate viviparity), a vertebrate blood-specific diet by both sexes, and obligate bacterial symbiosis. This work describes the comparative analysis of six Glossina genomes representing three sub-genera: Morsitans (G. morsitans morsitans, G. pallidipes, G. austeni), Palpalis (G. palpalis, G. fuscipes), and Fusca (G. brevipalpis) which represent different habitats, host preferences, and vectorial capacity. Results: Genomic analyses validate established evolutionary relationships and sub-genera. Syntenic analysis of Glossina relative …

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Integrating Temperature-Dependent Life Table Data Into Insect Life Cycle Model For Predicting The Potential Distribution Of Scapsipedus Icipe Hugel & Tanga, Magara H.J. Otieno, Monica A. Ayieko, Saliou Niassy, Daisy Salifu, Azrag G.A. Abdelmutalab, Khamis M. Fathiya, Sevgan Subramanian, Komi K.M. Fiaboe, Nana Roos, Sunday Ekesi, Chrysantus M. Tanga Sep 2019

Integrating Temperature-Dependent Life Table Data Into Insect Life Cycle Model For Predicting The Potential Distribution Of Scapsipedus Icipe Hugel & Tanga, Magara H.J. Otieno, Monica A. Ayieko, Saliou Niassy, Daisy Salifu, Azrag G.A. Abdelmutalab, Khamis M. Fathiya, Sevgan Subramanian, Komi K.M. Fiaboe, Nana Roos, Sunday Ekesi, Chrysantus M. Tanga

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Scapsipedus icipe Hugel and Tanga (Orthoptera: Gryllidae) is a newly described edible cricket species. Although, there is substantial interest in mass production of S. icipe for human food and animal feed, no information exists on the impact of temperature on their bionomics. Temperature-dependent development, survival, reproductive and life table parameters of S. icipe was generated and integrated into advanced Insect Life Cycle Modeling software to describe relative S. icipe population increase and spatial spread based on nine constant temperature conditions. We examined model predictions and implications for S. icipe potential distribution in Africa under current and future climate. These regions …

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Using Sibship Reconstructions To Understand The Relationship Between Larval Habitat Productivity And Oviposition Behaviour In Kenyan Anopheles Arabiensis, Joel O. Odero, Ulrike Fillinger, Emily J. Rippon, Daniel K. Masiga, David Weetman Aug 2019

Using Sibship Reconstructions To Understand The Relationship Between Larval Habitat Productivity And Oviposition Behaviour In Kenyan Anopheles Arabiensis, Joel O. Odero, Ulrike Fillinger, Emily J. Rippon, Daniel K. Masiga, David Weetman

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Background: Strategies for combatting residual malaria by targeting vectors outdoors are gaining importance as the limitations of primary indoor interventions are reached. Strategies to target ovipositing females or her offspring are broadly applicable because all mosquitoes require aquatic habitats for immature development irrespective of their biting or resting preferences. Oviposition site selection by gravid females is frequently studied by counting early instar larvae in habitats; an approach which is valid only if the number of larvae correlates with the number of females laying eggs. This hypothesis was tested against the alternative, that a higher abundance of larvae results from improved …

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A Bayesian Analysis Of Longitudinal Farm Surveys In Central Malawi Reveals Yield Determinants And Site-Specific Management Strategies, Han Wang, Sieglinde S. Snapp, Monica Fisher, Frederi Viens Aug 2019

A Bayesian Analysis Of Longitudinal Farm Surveys In Central Malawi Reveals Yield Determinants And Site-Specific Management Strategies, Han Wang, Sieglinde S. Snapp, Monica Fisher, Frederi Viens

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Understanding the challenges to increasing maize productivity in sub-Saharan Africa, especially agronomic factors that reduce on-farm crop yield, has important implications for policies to reduce national and global food insecurity. Previous research on the maize yield gap has tended to emphasize the size of the gap (theoretical vs. achievable yields), rather than what determines maize yield in specific contexts. As a result, there is insufficient evidence on the key agronomic and environmental factors that influence maize yield in a smallholder farm environment. In this study, we implemented a Bayesian analysis with plot-level longitudinal household survey data covering 1,197 plots and …

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Experimental Feeding Studies With Crickets And Locusts On The Use Of Feed Mixtures Composed Of Storable Feed Materials Commonly Used In Livestock Production, P. Straub, C. M. Tanga, I. Osuga, W. Windisch, S. Subramanian Aug 2019

Experimental Feeding Studies With Crickets And Locusts On The Use Of Feed Mixtures Composed Of Storable Feed Materials Commonly Used In Livestock Production, P. Straub, C. M. Tanga, I. Osuga, W. Windisch, S. Subramanian

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Insects such as the Mediterranean field cricket, Gryllus bimaculatus and the Desert locust, Schistocerca gregaria, are emerging as potential sources of human food and feed for livestock. High nutritive value and efficient feed conversion make them attractive for commercial production as novel livestock, but these properties strongly vary with the insects´ diet. Current mass-rearing protocols are based on fresh, non-storable feed materials. This requires constant supply and makes the systems sensitive to fluctuations regarding nutritional quality and safety. Hence there is a need to find storable, readily available feeds. Therefore, experimental diets were composed from the five different feed materials, …

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Agro-Ecological Options For Fall Armyworm (Spodoptera Frugiperda Je Smith)Management: Providing Low-Cost, Smallholder Friendly Solutions To An Invasive Pest, Rhett D. Harrison, Christian Thierfelder, Frédéric Baudron, Peter Chinwada, Charles Midega, Urs Schaffner, Johnnie Van Den Berg Aug 2019

Agro-Ecological Options For Fall Armyworm (Spodoptera Frugiperda Je Smith)Management: Providing Low-Cost, Smallholder Friendly Solutions To An Invasive Pest, Rhett D. Harrison, Christian Thierfelder, Frédéric Baudron, Peter Chinwada, Charles Midega, Urs Schaffner, Johnnie Van Den Berg

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Fall armyworm (FAW), a voracious agricultural pest native to North and South America, was first detected on the African continent in 2016 and has subsequently spread throughout the continent and across Asia. It has been predicted that FAW could cause up to $US13 billion per annum in crop losses throughout sub-Saharan Africa, thereby threatening the livelihoods of millions of poor farmers. In their haste to respond to FAW governments may promote indiscriminate use of chemical pesticides which, aside from human health and environmental risks, could undermine smallholder pest management strategies that depend to a large degree on natural enemies. Agro-ecological …

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The Influence Of Water And Nutrient Management On Oil Palm Yield Trends On A Large-Scale Plantation In Ghana, Tiemen Rhebergen, Thomas Fairhurst, Ken E. Giller, Shamie Zingore Jul 2019

The Influence Of Water And Nutrient Management On Oil Palm Yield Trends On A Large-Scale Plantation In Ghana, Tiemen Rhebergen, Thomas Fairhurst, Ken E. Giller, Shamie Zingore

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Oil palm (Eleais guineensisJacq.) production in West Africa is limited by poor soils and suboptimal climate. The potential to improve fruit bunch (FB) yields with appropriate water and nutrient management in Ghana is thus considerable. To assess the effects of water and nutrient management on oil palm yields, a 2 x 2 factorial randomized complete block design with irrigation and fertilizer was implemented for three years in the main oil palm production area of Western region, Ghana. Treatments included i) zero irrigation + zero fertilizer (control), ii) zero irrigation + fertilizer, iii) irrigation + zero fertilizer and iv) irrigation + …

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Seasonal Abundance Of Plutella Xylostella (Lepidoptera: Plutellidae) And Diversity Of Its Parasitoids Along Altitudinal Gradients Of The Eastern Afromontane, Benignus Valentine Ngowi, Henri Edouardo Zefack Tonnang, Fathiya Khamis, Evans Mungai Mwangi, Brigitte Nyambo, Paul Nduati Ndegwa, Sevgan Subramanian Jul 2019

Seasonal Abundance Of Plutella Xylostella (Lepidoptera: Plutellidae) And Diversity Of Its Parasitoids Along Altitudinal Gradients Of The Eastern Afromontane, Benignus Valentine Ngowi, Henri Edouardo Zefack Tonnang, Fathiya Khamis, Evans Mungai Mwangi, Brigitte Nyambo, Paul Nduati Ndegwa, Sevgan Subramanian

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Monthly field surveys of diamondback moth (DBM), Plutella xylostella (L.) and its parasitoids were conducted to assess seasonal abundance and diversity under changing altitude. Twenty-four crucifer farms spread across three altitudinal zones of Mount Kilimanjaro and Taita hills were sampled for the insects at monthly interval from 2013 to 2014. Diamondback moth abundance differed significantly between seasons (F3, 21 = 3.883, p = 0.024) in the high zone of Taita hills. The abundance among altitudinal zones of the two transects was not significantly different (Mt. Kilimanjaro: F2, 98 = 0.415, p = 0.661; Taita hills: F2, 116 = 0.303, p …

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Isopentyl Butanoate: Aggregation Pheromone Of The Brown Spiny Bug, Clavigralla Tomentosicollis (Hemiptera: Coreidae), And Kairomone For The Egg Parasitoid Gryon Sp. (Hymenoptera: Scelionidae), Hilaire Kpongbe, Johnnie Van Den Berg, Fathiya Khamis, Manuele Tamò, Baldwyn Torto Jul 2019

Isopentyl Butanoate: Aggregation Pheromone Of The Brown Spiny Bug, Clavigralla Tomentosicollis (Hemiptera: Coreidae), And Kairomone For The Egg Parasitoid Gryon Sp. (Hymenoptera: Scelionidae), Hilaire Kpongbe, Johnnie Van Den Berg, Fathiya Khamis, Manuele Tamò, Baldwyn Torto

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The brown spiny bug, Clavigralla tomentosicollis Stål (Hemiptera: Coreidae) is a key pest of leguminous crops in many countries in Africa, causing significant yield losses especially in cowpea, pigeon pea and common beans. Although C. tomentosicollis uses olfaction to aggregate, little is known about the identity of the aggregation pheromone. This study aimed to identify the aggregation pheromone of C. tomentosicollis and to test its potential role in the behavior of its egg parasitoid, Gryon sp. In Y-tube olfactometer bioassays, only male volatiles strongly attracted both sexes of C. tomentosicollis. Coupled gas chromatography/electroantennographic detection (GC/EAD) and GC/mass spectrometry were used …

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Nitrogen Leaching Losses And Balances In Conventional And Organic Farming Systems In Kenya, Martha W. Musyoka, Noah Adamtey, Anne W. Muriuki, David Bautze, Edward N. Karanja, Monica Mucheru-Muna, Komi K.M. Fiaboe, Georg Cadisch Jul 2019

Nitrogen Leaching Losses And Balances In Conventional And Organic Farming Systems In Kenya, Martha W. Musyoka, Noah Adamtey, Anne W. Muriuki, David Bautze, Edward N. Karanja, Monica Mucheru-Muna, Komi K.M. Fiaboe, Georg Cadisch

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Organic farming has been proposed as a solution to foster agricultural sustainability and mitigate the negative environmental impacts of conventional farming. This study assessed N losses and soil surface N balances in conventional and organic farming systems in a sub-humid and semi-humid (Chuka and Thika) sites in Kenya. Nitrate–N (NO3−–N) leached was trapped at 1 m depth using the Self Integrating Accumulator core method and the changes in mineral-N were assessed at different soil depths and different crop growth stages. Both conventional and organic farming systems lost substantial amounts of NO3−–N at the early growth stages of all the crops. …

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Frugivorous Insects Reared From Chytranthus Obliquinervis Radlk. (Sapindales: Sapindaceae) With The Description Of A New Monophagous Species Of Grapholita Treitschke (Lepidoptera: Tortricidae), Robert S. Copeland, Józef Razowski Jul 2019

Frugivorous Insects Reared From Chytranthus Obliquinervis Radlk. (Sapindales: Sapindaceae) With The Description Of A New Monophagous Species Of Grapholita Treitschke (Lepidoptera: Tortricidae), Robert S. Copeland, Józef Razowski

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Ripe fruits of Chytranthus obliquinervis were sampled from a tree in Buda Forest in coastal Kenya. Four species of insects were reared from the fruits, two species of Tephritidae, an undescribed species of gelechiid moth, and a new species of tortricid moth, Grapholita chytranthusi Razowski, sp. n., described herein. No parasitoids were reared. Notes on the biology, distribution, and conservation status of the host and its pests are included.

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Responses Of Glossina Fuscipes Fuscipes To Visually Attractive Stationary Devices Baited With 4-Methylguaiacol And Certain Repellent Compounds In Waterbuck Odour, Njelembo J. Mbewe, Rajinder K. Saini, Janet Irungu, Abdullahi A. Yusuf, Christian W.W. Pirk, Baldwyn Torto Jul 2019

Responses Of Glossina Fuscipes Fuscipes To Visually Attractive Stationary Devices Baited With 4-Methylguaiacol And Certain Repellent Compounds In Waterbuck Odour, Njelembo J. Mbewe, Rajinder K. Saini, Janet Irungu, Abdullahi A. Yusuf, Christian W.W. Pirk, Baldwyn Torto

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Background: A blend of compounds (pentanoic acid, guaiacol, δ-octalactone and geranylacetone) identified in waterbuck (Kobus defassa) body odour referred to as waterbuck repellent compounds (WRC) and a synthetic repellent 4-methylguaiacol have previously been shown to repel tsetse flies from the morsitans group. However, these repellents have not been evaluated on palpalis group tsetse flies. In this study, we evaluated the effect of these repellents on catches of Glossina fuscipes fuscipes (major vector of human sleeping sickness) in biconical traps and on sticky small targets which are visually attractive to palpalis group flies. The attractive devices were baited with different doses …

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A Comparative Analysis Of Planetscope And Sentinel Sentinel-2 Space-Borne Sensors In Mapping Striga Weed Using Guided Regularised Random Forest Classification Ensemble, B. T. Mudereri, T. Dube, E. M. Adel-Rahman, S. Niassy, E. Kimathi, Z. Khan, T. Landmann Jun 2019

A Comparative Analysis Of Planetscope And Sentinel Sentinel-2 Space-Borne Sensors In Mapping Striga Weed Using Guided Regularised Random Forest Classification Ensemble, B. T. Mudereri, T. Dube, E. M. Adel-Rahman, S. Niassy, E. Kimathi, Z. Khan, T. Landmann

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Weeds are one of the major restrictions to sustaining crop productivity. Weeds often outcompete crops for nutrients, soil moisture, solar radiation, space and provide platforms for breeding of pests and diseases. The ever-growing global food insecurity triggers the need for spatially explicit innovative geospatial technologies that can deliver timely detection of weeds within agro-ecological systems. This will help pinpoint maize fields to be prioritized for weed control. Satellite remote sensing offers incomparable opportunities for precision agriculture, ecological applications and vegetation characterisation, with vast socioeconomic benefits. This work compares and evaluates the strength of Sentinel-2 (S2) satellite with the constellation of …

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Host Species And Site Of Collection Shape The Microbiota Of Rift Valley Fever Vectors In Kenya, David P. Tchouassi, Ephantus J. Muturi, Samwel O. Arum, Chang Hyun Kim, Christopher J. Fields, Baldwyn Torto Jun 2019

Host Species And Site Of Collection Shape The Microbiota Of Rift Valley Fever Vectors In Kenya, David P. Tchouassi, Ephantus J. Muturi, Samwel O. Arum, Chang Hyun Kim, Christopher J. Fields, Baldwyn Torto

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The composition and structure of microbial communities associated with mosquitoes remain poorly understood despite their important role in host biology and potential to be harnessed as novel strategies for mosquito-borne disease control. We employed MiSeq sequencing of the 16S rRNA gene amplicons to characterize the bacterial flora of field-collected populations of Aedes mcintoshi and Aedes ochraceus, the primary vectors of Rift Valley fever (RVF) virus in Kenya. Proteobacteria (53.5%), Firmicutes (22.0%) and Actinobacteria (10.0%) were the most abundant bacterial phyla accounting for 85.5% of the total sequences. Non-metric multi-dimensional scaling plots based on Bray-Curtis dissimilarities revealed a clear grouping of …

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Caterpillar-Induced Plant Volatiles Attract Conspecific And Heterospecific Adults For Oviposition Within A Community Of Lepidopteran Stemborers On Maize Plant, Bonoukpoè Mawuko Sokame, Eric Siaw Ntiri, Peter Ahuya, Baldwyn Torto, Bruno Pierre Le Ru, Dora Chao Kilalo, Gerald Juma, Paul André Calatayud Jun 2019

Caterpillar-Induced Plant Volatiles Attract Conspecific And Heterospecific Adults For Oviposition Within A Community Of Lepidopteran Stemborers On Maize Plant, Bonoukpoè Mawuko Sokame, Eric Siaw Ntiri, Peter Ahuya, Baldwyn Torto, Bruno Pierre Le Ru, Dora Chao Kilalo, Gerald Juma, Paul André Calatayud

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Olfactory cues may influence host plant preferences for oviposition of female moths within a community of stemborers that utilise the same resource. This study aimed to evaluate plant preferences for oviposition of gravid females of noctuid stemborers, Busseola fusca and Sesamia calamistis, and the crambid Chilo partellus for uninfested maize plants and plants infested by conspecific or heterospecific larvae. The involvement of volatile organic compounds (VOCs) emitted by uninfested and maize plants infested by conspecific or heterospecific larvae on moth orientation was studied in Y-tube olfactometer assays and in the field. All gravid female moths significantly preferred VOCs emitted by …

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Mosquito Microevolution Drives Plasmodium Falciparum Dynamics, Markus Gildenhard, Evans K. Rono, Assetou Diarra, Anne Boissière, Priscila Bascunan, Paola Carrillo-Bustamante, Djeneba Camara, Hanne Krüger, Modibo Mariko, Ramata Mariko, Paul Mireji, Sandrine E. Nsango, Julien Pompon, Yara Reis, Martin K. Rono, Pamela B. Seda, Janis Thailayil, Alou Traorè, Cynthia V. Yapto, Parfait Awono-Ambene, Roch K. Dabiré, Abdulaye Diabaté, Daniel Masiga, Flaminia Catteruccia, Isabelle Morlais, Mouctar Diallo, Djibril Sangare, Elena A. Levashina Jun 2019

Mosquito Microevolution Drives Plasmodium Falciparum Dynamics, Markus Gildenhard, Evans K. Rono, Assetou Diarra, Anne Boissière, Priscila Bascunan, Paola Carrillo-Bustamante, Djeneba Camara, Hanne Krüger, Modibo Mariko, Ramata Mariko, Paul Mireji, Sandrine E. Nsango, Julien Pompon, Yara Reis, Martin K. Rono, Pamela B. Seda, Janis Thailayil, Alou Traorè, Cynthia V. Yapto, Parfait Awono-Ambene, Roch K. Dabiré, Abdulaye Diabaté, Daniel Masiga, Flaminia Catteruccia, Isabelle Morlais, Mouctar Diallo, Djibril Sangare, Elena A. Levashina

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Malaria, a major cause of child mortality in Africa, is engendered by Plasmodium parasites that are transmitted by anopheline mosquitoes. Fitness of Plasmodium parasites is closely linked to the ecology and evolution of its anopheline vector. However, whether the genetic structure of vector populations impacts malaria transmission remains unknown. Here, we describe a partitioning of the African malaria vectors into generalists and specialists that evolve along ecological boundaries. We next identify the contribution of mosquito species to Plasmodium abundance using Granger causality tests for time-series data collected over two rainy seasons in Mali. We find that mosquito microevolution, defined by …

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Zebra Skin Odor Repels The Savannah Tsetse Fly, Glossina Pallidipes (Diptera: Glossinidae), Olabimpe Y. Olaide, David P. Tchouassi, Abdullahi A. Yusuf, Christian W.W. Pirk, Daniel K. Masiga, Rajinder K. Saini, Baldwyn Torto Jun 2019

Zebra Skin Odor Repels The Savannah Tsetse Fly, Glossina Pallidipes (Diptera: Glossinidae), Olabimpe Y. Olaide, David P. Tchouassi, Abdullahi A. Yusuf, Christian W.W. Pirk, Daniel K. Masiga, Rajinder K. Saini, Baldwyn Torto

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Background African trypanosomosis, primarily transmitted by tsetse flies, remains a serious public health and economic challenge in sub-Saharan Africa. Interventions employing natural repellents from non-preferred hosts of tsetse flies represent a promising management approach. Although zebras have been identified as non-preferred hosts of tsetse flies, the basis for this repellency is poorly understood. We hypothesized that zebra skin odors contribute to their avoidance by tsetse flies. Methodology/Principal findings We evaluated the effect of crude zebra skin odors on catches of wild savannah tsetse flies (Glossina pallidipes Austen, 1903) using unbaited Ngu traps compared to the traps baited with two known …

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Unexpected Diversity Of Wolbachia Associated With Bactrocera Dorsalis (Diptera: Tephritidae) In Africa, Joseph Gichuhi, Fathiya M. Khamis, Johnnie Van Den Berg, Sunday Ekesi, Jeremy K. Herren Jun 2019

Unexpected Diversity Of Wolbachia Associated With Bactrocera Dorsalis (Diptera: Tephritidae) In Africa, Joseph Gichuhi, Fathiya M. Khamis, Johnnie Van Den Berg, Sunday Ekesi, Jeremy K. Herren

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Bactrocera dorsalis (Hendel) is an important pest of fruit-bearing plants in many countries worldwide. In Africa, this pest has spread rapidly and has become widely established since the first invasion report in 2003. Wolbachia is a vertically transmitted endosymbiont that can significantly influence aspects of the biology and, in particular, the reproduction of its host. In this study, we screened B. dorsalis specimens collected from several locations in Africa between 2005 and 2017 for Wolbachia using a PCR-based assay to target the Wolbachia surface protein wsp. Of the 357 individuals tested, 10 were positive for Wolbachia using the wsp assay. …

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Population Dynamics Of The Diamondback Moth And Its Parasitoids In Zimbabwe, Rudo Sithole, Casper Nyamukondiwa, Peter Chinwada, Bernhard Lohr Jun 2019

Population Dynamics Of The Diamondback Moth And Its Parasitoids In Zimbabwe, Rudo Sithole, Casper Nyamukondiwa, Peter Chinwada, Bernhard Lohr

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Temporal population dynamics of the diamondback moth (DBM), Plutella xylostella (L.) and its parasitoids were studied for a continuous 13-months period at two sites in Zimbabwe, vis Henderson and Mutoko. Our results showed that mean DBM numbers of 2.2 and 2.9 per plant for Henderson and Mutoko, respectively were not significantly different (p = 0.12). At Henderson, the DBM numbers achieved a pre-winter peak in February and a post-winter peak in October, while at Mutoko the pre-winter and post-winter peaks were reached a month earlier, in January and September, respectively. A total of four parasitoid species, comprising Cotesia vestalis, Oomyzus …

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Serological Evidence Of Flavivirus Circulation In Human Populations In Northern Kenya: An Assessment Of Disease Risk 2016-2017, E. Chepkorir, D. P. Tchouassi, S. L. Konongoi, J. Lutomiah, C. Tigoi, Z. Irura, F. Eyase, M. Venter, R. Sang May 2019

Serological Evidence Of Flavivirus Circulation In Human Populations In Northern Kenya: An Assessment Of Disease Risk 2016-2017, E. Chepkorir, D. P. Tchouassi, S. L. Konongoi, J. Lutomiah, C. Tigoi, Z. Irura, F. Eyase, M. Venter, R. Sang

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Background: Yellow fever, Dengue, West Nile and Zika viruses are re-emerging mosquito-borne Flaviviruses of public health concern. However, the extent of human exposure to these viruses and associated disease burden in Kenya and Africa at large remains unknown. We assessed the seroprevalence of Yellow fever and other Flaviviruses in human populations in West Pokot and Turkana Counties of Kenya. These areas border Uganda, South Sudan and Ethiopia where recent outbreaks of Yellow fever and Dengue have been reported, with possibility of spillover to Kenya. Methodology: Human serum samples collected through a cross-sectional survey in West Pokot and Turkana Counties were …

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Effect Of Larval Density And Substrate Quality On The Wing Geometry Of Stomoxys Calcitrans L. (Diptera: Muscidae), Steve B.S. Baleba, Daniel Masiga, Baldwyn Torto, Christopher W. Weldon, Merid N. Getahun May 2019

Effect Of Larval Density And Substrate Quality On The Wing Geometry Of Stomoxys Calcitrans L. (Diptera: Muscidae), Steve B.S. Baleba, Daniel Masiga, Baldwyn Torto, Christopher W. Weldon, Merid N. Getahun

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Background: In insects, oviposition decisions may lead to egg deposition in substrates with different larval density and nutritional levels. Individuals developing in such substrates may present plasticity in their phenotype. Here, we investigated the effect of two factors related to oviposition decisions, namely larval density and substrate quality, on the wing size and wing shape of the stable fly, Stomoxys calcitrans L. (Diptera: Muscidae). Methods: We reared S. calcitrans larvae at different densities (5, 15 and 25) and on different substrates (camel, cow, donkey and sheep dung). For each fly that emerged, we recorded body weight, and detached, slide-mounted and …

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Modelling Appropriate Use Of Trypanocides To Restrict Wide-Spread Multi-Drug Resistance During Chemotherapy Of Animal African Trypanosomiasis, Ibrahim I. Wangwe, Sarah A. Wamwenje, Caroline Mirieri, Nicodemus M. Masila, Lillian Wambua, Benard W. Kulohoma May 2019

Modelling Appropriate Use Of Trypanocides To Restrict Wide-Spread Multi-Drug Resistance During Chemotherapy Of Animal African Trypanosomiasis, Ibrahim I. Wangwe, Sarah A. Wamwenje, Caroline Mirieri, Nicodemus M. Masila, Lillian Wambua, Benard W. Kulohoma

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Trypanocide resistance remains a huge challenge in the management of animal African trypanosomiasis. Paucity of data on the prevalence of multi-drug resistant trypanosomes has greatly hindered optimal veterinary management practices. We use mathematical model predictions to highlight appropriate drug regimens that impede trypanocide resistance development in cattle. We demonstrate that using drugs in decreasing resistance order results in a negligible increase in number of cattle with resistant infection, in contrast to a more pronounced increase from trypanocide use in increasing resistance order. We demonstrate that the lowest levels of trypanocide resistance are achieved with combination therapy. We also show that …

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