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Articles 661 - 690 of 1443

Full-Text Articles in Life Sciences

Proximate Composition And In Vitro Protein Digestibility Of Extruded Aquafeeds Containing Acheta Domesticus And Hermetia Illucens Fractions, F. G. Irungu, C. M. Mutungi, A. K. Faraj, H. Affognon, S. Ekesi, D. Nakimbugwe, K. K.M. Fiaboe Jan 2018

Proximate Composition And In Vitro Protein Digestibility Of Extruded Aquafeeds Containing Acheta Domesticus And Hermetia Illucens Fractions, F. G. Irungu, C. M. Mutungi, A. K. Faraj, H. Affognon, S. Ekesi, D. Nakimbugwe, K. K.M. Fiaboe

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Major protein sources for feed manufacture have become costly, and this has led to increased cost of products such as aquafeeds. This has dampening effect on fish production especially in developing countries, and has necessitated a search for alternative protein sources in processed feeds. The effects of extrusion on aquafeed blends containing fractions of adult cricket (Acheta domesticus) meal (ACM) or black soldier fly (Hermetia illucens) pre-pupae meal (BSFM) on proximate composition and in vitro protein digestibility were investigated. Extrusion resulted in higher contents of protein and nitrogen free extract, and lower contents of ether extract and crude fibre as …

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Farmers’ Perception And Control Practices Against The Invasive Red Spider Mite (Tetranychus Evansi Baker & Pritchard) In Benin, G. Y. Azandémè-Hounmalon, H. D. Affognon, F. Assogba-Komlan, M. Tamò, K. K.M. Fiaboe, S. Kreiter, T. Martin Jan 2018

Farmers’ Perception And Control Practices Against The Invasive Red Spider Mite (Tetranychus Evansi Baker & Pritchard) In Benin, G. Y. Azandémè-Hounmalon, H. D. Affognon, F. Assogba-Komlan, M. Tamò, K. K.M. Fiaboe, S. Kreiter, T. Martin

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Tetranychus evansi (Acari: Tetranychidae), is an important pest of solanaceous plants in Benin where it damages tomato (Solanum lycopersicum L.; Solanaceae), African eggplant (S. macrocarpon L.; Solanaceae), purple amaranth (Amaranthus cruentus L.; Amaranthaceae). The objective of the present study was to evaluate the intensity of T. evansi damage and impact of farmers’ control practices in Benin. Two surveys were conducted between 2013 and 2016. The first survey revealed Tetranychus evansi as the only mite, causing production losses of 65% for African eggplant, 56% for tomato and 25% for purple amaranth. To protect the infested crops, growers sprayed various synthetic pesticides …

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Insect Net: A Novel Technology To Promote Integrated Pest Management On Horticultural Crops In Africa, T. Martin, M. Saidi, S. Niassy, S. Simon, F. Vidogbena, L. Parrot, S. Ekesi, E. Deletre, S. Subramanian, F. Assogba-Komlan, V. Baird, K. K.M. Fiaboe, M. Ngouajio, J. E. Simon, A. Ratnadass Jan 2018

Insect Net: A Novel Technology To Promote Integrated Pest Management On Horticultural Crops In Africa, T. Martin, M. Saidi, S. Niassy, S. Simon, F. Vidogbena, L. Parrot, S. Ekesi, E. Deletre, S. Subramanian, F. Assogba-Komlan, V. Baird, K. K.M. Fiaboe, M. Ngouajio, J. E. Simon, A. Ratnadass

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Fruits and vegetables are important commodities in global agriculture. However, in sub-Saharan Africa, production is sub-optimal in terms of yield, quality and environmental health practices due to several constraints such as insect pests which reduce yields through direct damage, or indirectly as disease vectors often promoting microbial diseases. Pest control still relies mainly on chemicals with their associated risks of resistance selection and toxicity to humans and environment. Several alternatives including biopesticides, semiochemical and nets are being explored in pest management. Insect nets applied on tomatoes, cabbages, beans and leafy vegetables protect them from flies, butterflies, moths, albeit to a …

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Haematology Of N’Dama And West African Shorthorn Cattle Herds Under Natural Trypanosoma Vivax Challenge In Ghana, Ebenezer Yaw Ganyo, Johnson N. Boampong, Daniel K. Masiga, Jandouwe Villinger, Paa Kobina Turkson Jan 2018

Haematology Of N’Dama And West African Shorthorn Cattle Herds Under Natural Trypanosoma Vivax Challenge In Ghana, Ebenezer Yaw Ganyo, Johnson N. Boampong, Daniel K. Masiga, Jandouwe Villinger, Paa Kobina Turkson

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Background: Animal trypanosomosis is a major cause of economic loss in livestock production in Africa. A suggested control measure is to use breeds with traits of trypanotolerance. The study examines the effect of natural Trypanosoma vivax challenge on haematological parameters in two trypanotolerant cattle [N’Dama and West African Shorthorn (WASH)] herds. Methods: Trypanosoma vivax-specific primers were used to diagnose T. vivax infection in an N’Dama herd at Cape Coast in southern Ghana and a WASH herd at Chegbani in northern Ghana from May to July 2011 in a cross-sectional study. Levels of haematological parameters comprising packed cell volume (PCV), haemoglobin …

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Suitability Of Egg Hatching Conditions And Commonly Available Food Plants For Rearing The Long-Horned Grasshopper Ruspolia Differens Serville (Orthoptera: Tettigoniidae), G. Ssepuuya, C. M. Tanga, I. Yekko, F. Sengendo, C. T. Ndagire, K. K.M. Fiaboe, J. Karungi, D. Nakimbugwe Jan 2018

Suitability Of Egg Hatching Conditions And Commonly Available Food Plants For Rearing The Long-Horned Grasshopper Ruspolia Differens Serville (Orthoptera: Tettigoniidae), G. Ssepuuya, C. M. Tanga, I. Yekko, F. Sengendo, C. T. Ndagire, K. K.M. Fiaboe, J. Karungi, D. Nakimbugwe

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Efforts to promote sustainable production and processing of Ruspolia differens Serville (Orthoptera: Tettigoniidae) as a viable agribusiness model for enhancing food and nutrition security have gained momentum. However, the inexistence of rearing techniques adapted to this insect creates uncertainty regarding the effectiveness of up-scaling production. This study evaluated the effect of five temperatures (26, 28, 30, 32 and 34 °C) on egg development time, percentage hatchability and nymphal weight at hatching. It also evaluated the average weekly wet weight attained by R. differens and percentage survival during growth when reared at 30 °C on four different food plant diets. The …

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Influence Of Prolonged Dietary Experience During The Larval Stage On Novel Odour Preferences In Adults Of Noctuid Stem Borer Moths (Lepidoptera: Noctuidae), Christophe Petit, Peter Ahuya, Bruno Le Ru, Laure Kaiser-Arnauld, Myriam Harry, Paul André Calatayud Jan 2018

Influence Of Prolonged Dietary Experience During The Larval Stage On Novel Odour Preferences In Adults Of Noctuid Stem Borer Moths (Lepidoptera: Noctuidae), Christophe Petit, Peter Ahuya, Bruno Le Ru, Laure Kaiser-Arnauld, Myriam Harry, Paul André Calatayud

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In Lepidoptera, larval dietary experience of volatile cues can induce adult preference for these cues. However, such induction may require several generations, depending in part on the degree of specialization of the insects. In a previous study, using species of noctuid stem borers with different diet breadths, namely the polyphagous Sesamia nonagrioides, the oligophagous Busseola fusca and monophagous Busseola nairobica, it was shown that in S. nonagrioides, one generation was enough to induce a preference for vanillin in the resulting gravid females, whereas even two generations failed to induce a response in adults of Busseola spp. In this study, we …

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Essential Oils Of Indigenous Plants Protect Livestock From Infestations Of Rhipicephalus Appendiculatus And Other Tick Species In Herds Grazing In Natural Pastures In Western Kenya, Wycliffe Wanzala, Ahmed Hassanali, Wolfgang Richard Mukabana, Willem Takken Jan 2018

Essential Oils Of Indigenous Plants Protect Livestock From Infestations Of Rhipicephalus Appendiculatus And Other Tick Species In Herds Grazing In Natural Pastures In Western Kenya, Wycliffe Wanzala, Ahmed Hassanali, Wolfgang Richard Mukabana, Willem Takken

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The effects of formulated essential oils of Tagetes minuta and Tithonia diversifolia on Rhipicephalus appendiculatus infesting livestock were evaluated in semi-field experiments. Forty-five zebu cattle naturally infested with ticks were randomly selected from 15 herds, three animals from each. Of the three animals within each herd, one was treated with 1 g of petroleum jelly (control), one with 1 g of essential oil of T. minuta and one with 1 g of essential oil of T. diversifolia on the inner side of ear pinna, the preferred feeding site of R. appendiculatus. Tick infestation on each treated host animal was monitored …

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Residual Contact Toxicity And Repellence Of Cupressus Lusitanica Miller And Eucalyptus Saligna Smith Essential Oils Against Major Stored Product Insect Pests, Philip K. Bett, Arop L. Deng, Joshua O. Ogendo, Samuel T. Kariuki, Maud Kamatenesi-Mugisha, Joel M. Mihale, Baldwyn Torto Dec 2017

Residual Contact Toxicity And Repellence Of Cupressus Lusitanica Miller And Eucalyptus Saligna Smith Essential Oils Against Major Stored Product Insect Pests, Philip K. Bett, Arop L. Deng, Joshua O. Ogendo, Samuel T. Kariuki, Maud Kamatenesi-Mugisha, Joel M. Mihale, Baldwyn Torto

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In an effort to find eco-friendly alternatives to synthetic pesticides in grain storage, residual contact toxicity and repellence of Cupressus lusitanica and Eucalyptus saligna leaf essential oils were evaluated against adult Tribolium castaneum, Acanthoscelides obtectus and Sitophilus zeamais. In bioassays, oil was applied at 0.00, 0.05, 0.10, 0.15 and 0.20% v/w to wheat and bean grains and stored for 30–120 days after which test insects were introduced into sub-samples of treated grains. Both oils at 0.20% v/w and 120 days grain storage duration caused a mortality of 5.0–65.0% in test insects whereas in the repellence bioassay, at same doses and …

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Dengue And Yellow Fever Virus Vectors: Seasonal Abundance, Diversity And Resting Preferences In Three Kenyan Cities, Sheila B. Agha, David P. Tchouassi, Armanda D.S. Bastos, Rosemary Sang Dec 2017

Dengue And Yellow Fever Virus Vectors: Seasonal Abundance, Diversity And Resting Preferences In Three Kenyan Cities, Sheila B. Agha, David P. Tchouassi, Armanda D.S. Bastos, Rosemary Sang

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Background: The transmission patterns of dengue (DENV) and yellow fever (YFV) viruses, especially in urban settings, are influenced by Aedes (Stegomyia) mosquito abundance and behavior. Despite recurrent dengue outbreaks on the Kenyan coast, these parameters remain poorly defined in this and other areas of contrasting dengue endemicity in Kenya. In assessing the transmission risk of DENV/YFV in three Kenyan cities, we determined adult abundance and resting habits of potential Aedes (Stegomyia) vectors in Kilifi (dengue-outbreak prone), and Nairobi and Kisumu (no dengue outbreaks reported). In addition, mosquito diversity, an important consideration for changing mosquito-borne disease dynamics, was compared. Methods: Between …

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Mechanisms Of Plasmodium-Enhanced Attraction Of Mosquito Vectors, Annette O. Busula, Niels O. Verhulst, Teun Bousema, Willem Takken, Jetske G. De Boer Dec 2017

Mechanisms Of Plasmodium-Enhanced Attraction Of Mosquito Vectors, Annette O. Busula, Niels O. Verhulst, Teun Bousema, Willem Takken, Jetske G. De Boer

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Evidence is accumulating that Plasmodium-infected vertebrates are more attractive to mosquitoes than noninfected hosts, particularly when high levels of gametocytes are present. Changes in host odour have been suggested as a likely target for parasite manipulation because olfactory cues are crucial to mosquitoes in search of a bloodmeal host. This review discusses two routes that may lead to such changes: (i) direct emission of volatile products from malaria parasites, and (ii) changes in skin microbial composition that could lead to changes in the vertebrate odour profile. Here we synthesize what is known and suggest how further research can increase our …

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Welwitschianalol A And B, Two Cyclohexene Derivatives And Other Insecticidal Constituents Of Caesalpinia Welwitschiana (Oliv.) Brenan, Flaure Rosette Ehawa Essoung, Brice Mittérant Mba'ning, Wilber Lwande, Silvère Augustin Ngouela, Etienne Tsamo, Sumesh Chander Chhabra, Ahmed Hassanali, Russell John Cox Dec 2017

Welwitschianalol A And B, Two Cyclohexene Derivatives And Other Insecticidal Constituents Of Caesalpinia Welwitschiana (Oliv.) Brenan, Flaure Rosette Ehawa Essoung, Brice Mittérant Mba'ning, Wilber Lwande, Silvère Augustin Ngouela, Etienne Tsamo, Sumesh Chander Chhabra, Ahmed Hassanali, Russell John Cox

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Crude methanol extract of the leaves of Caesalpinia welwitschiana was found to possess moderate larvicidal activity against second-instar larvae of Tuta absoluta Meyrick. Bioassay-guided fractionation of this extract led to the isolation of two oxygenated cyclohexene derivatives, welwitschianalol A (1, (1α,2β)-2-acetoxy-1-hydroxy-1- benzoyloxymethylcyclohex-5-ene) and B (2, (1α,2β)-2- benzoyloxy −1-cinnamoyloxymethyl-1-hydroxycyclohex-5-ene), together with eight known compounds, comprising bonducellin, dipteryxic acid, 3′-hydroxygenkwarin, afzelin, quercitrin, myricitrin, methyl gallate and gallic acid. The structures of the unknown compounds as well as those of the known ones were elucidated based on their MS, 1D and 2D NMR spectra, and in the case of known compounds, by comparison …

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Diversity And Abundance Of Lepidopteran Stem Borer Natural Enemies In Natural And Cultivated Habitats In Botswana, Reyard Mutamiswa, Eva Moeng, Bruno P. Le Ru, Des E. Conlong, Yoseph Assefa, Muluken Goftishu, Casper Nyamukondiwa Dec 2017

Diversity And Abundance Of Lepidopteran Stem Borer Natural Enemies In Natural And Cultivated Habitats In Botswana, Reyard Mutamiswa, Eva Moeng, Bruno P. Le Ru, Des E. Conlong, Yoseph Assefa, Muluken Goftishu, Casper Nyamukondiwa

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Lepidopteran stem-borers in Africa are attacked by diverse natural enemies in natural and cultivated environments. Field surveys of stem-borer natural enemies and associated host plants were conducted during the austral summers of 2014/15 and 2015/16 on natural and cultivated habitats across Botswana to determine their diversity and relative abundance. In cultivated habitats, the most common parasitoids of larvae were Cotesia flavipes Cameron, C. sesamiae (Cameron), and of pupae, Pediobius furvus Gahan and Gambroides nimbipennis Seyrig. In natural habitats, the larval parasitoids Chelonus curvimaculatus Cameron and Goniozus indicus Ashmead were recorded, along with the pupal parasitoid, Dentichasmias busseolae Heinrich. Furthermore, the …

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Relationship Between Oviposition, Virulence Gene Expression And Parasitism Success In Cotesia Typhae Nov. Sp. Parasitoid Strains, R. Benoist, C. Chantre, C. Capdevielle-Dulac, M. Bodet, F. Mougel, P. A. Calatayud, S. Dupas, E. Huguet, R. Jeannette, J. Obonyo, C. Odorico, J. F. Silvain, B. Le Ru, L. Kaiser Dec 2017

Relationship Between Oviposition, Virulence Gene Expression And Parasitism Success In Cotesia Typhae Nov. Sp. Parasitoid Strains, R. Benoist, C. Chantre, C. Capdevielle-Dulac, M. Bodet, F. Mougel, P. A. Calatayud, S. Dupas, E. Huguet, R. Jeannette, J. Obonyo, C. Odorico, J. F. Silvain, B. Le Ru, L. Kaiser

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Studying mechanisms that drive host adaptation in parasitoids is crucial for the efficient use of parasitoids in biocontrol programs. Cotesia typhae nov. sp. (Fernández-Triana) (Hymenoptera: Braconidae) is a newly described parasitoid of the Mediterranean corn borer Sesamia nonagrioides (Lefebvre) (Lepidoptera: Noctuidae). Braconidae are known for their domesticated bracovirus, which is injected with eggs in the host larva to overcome its resistance. In this context, we compared reproductive success traits of four Kenyan strains of C. typhae on a French and a Kenyan populations of its host. Differences were found between the four strains and the two most contrasted ones were …

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Impact Assessment Of Push-Pull Pest Management On Incomes, Productivity And Poverty Among Smallholder Households In Eastern Uganda, Ruth T. Chepchirchir, Ibrahim Macharia, Alice W. Murage, Charles A.O. Midega, Zeyaur R. Khan Dec 2017

Impact Assessment Of Push-Pull Pest Management On Incomes, Productivity And Poverty Among Smallholder Households In Eastern Uganda, Ruth T. Chepchirchir, Ibrahim Macharia, Alice W. Murage, Charles A.O. Midega, Zeyaur R. Khan

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The paper evaluates the impact of adoption of push-pull technology (PPT) on household welfare in terms of productivity, incomes and poverty status measured through per-capita food consumption in eastern Uganda. Push-pull is a habitat management strategy for the integrated management of stemborers, striga weeds and poor soil fertility involving the use of a natural repellent (push) and an attractant (pull). This biological technology simultaneously reduces the impact of three major production constraints to cereal-livestock farming in Africa − pests, weeds and poor soil. Cross sectional survey data were collected from 560 households in four districts in the region (Busia, Tororo, …

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Identification Of Kairomones Of Second Instar Nymphs Of The Variegated Coffee Bug Antestiopsis Thunbergii (Heteroptera: Pentatomidae), Teresiah N. Njihia, Baldwyn Torto, Lucy K. Murungi, Janet Irungu, Dickson M. Mwenda, Régis Babin Dec 2017

Identification Of Kairomones Of Second Instar Nymphs Of The Variegated Coffee Bug Antestiopsis Thunbergii (Heteroptera: Pentatomidae), Teresiah N. Njihia, Baldwyn Torto, Lucy K. Murungi, Janet Irungu, Dickson M. Mwenda, Régis Babin

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The variegated coffee bug Antestiopsis thunbergii Gmelin is a key pest of Coffea arabica in East Africa. Although the bug feeds on various parts of the coffee plant, it has a strong preference for mature green berries which are essential for the bug to complete its life cycle, reproduce and enhance its longevity. To locate mature green coffee berries, we hypothesized that second instar nymphs, which are the most mobile and active feeding immature stage of the bug, must rely on key volatile compounds emitted by the host for recognition. We tested this hypothesis using behavioral and electrophysiological assays and …

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Temperature-Dependent Models Of Development And Survival Of An Insect Pest Of African Tropical Highlands, The Coffee Antestia Bug Antestiopsis Thunbergii (Hemiptera: Pentatomidae), Abdelmutalab G.A. Azrag, Lucy K. Murungi, Henri E.Z. Tonnang, Dickson Mwenda, Régis Babin Dec 2017

Temperature-Dependent Models Of Development And Survival Of An Insect Pest Of African Tropical Highlands, The Coffee Antestia Bug Antestiopsis Thunbergii (Hemiptera: Pentatomidae), Abdelmutalab G.A. Azrag, Lucy K. Murungi, Henri E.Z. Tonnang, Dickson Mwenda, Régis Babin

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The antestia bug Antestiopsis thunbergii (Hemiptera: Pentatomidae) is a major pest of Arabica coffee in African tropical highlands. It feeds on coffee plant vegetative parts and berries leading to a direct reduction in coffee yield and quality. This study aimed to determine A. thunbergii thermal requirements, and to obtain new information on the pest demography as influenced by temperature. Temperature-dependent models were developed using the Insect Life Cycle Modelling software (ILCYM) through a complete life table study at seven constant temperatures in the range 18–32 °C. Non-linear functions were fitted to A. thunbergii development, mortality, fecundity and senescence. Model parameters …

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Strong Spatial-Temporal Patterns In Maize Yield Response To Nutrient Additions In African Smallholder Farms, Samuel Njoroge, Antonius G.T. Schut, Ken E. Giller, Shamie Zingore Dec 2017

Strong Spatial-Temporal Patterns In Maize Yield Response To Nutrient Additions In African Smallholder Farms, Samuel Njoroge, Antonius G.T. Schut, Ken E. Giller, Shamie Zingore

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Large variability in crop responses to macronutrient application at various spatial scales present challenges for developing effective fertilizer recommendations for crop production in smallholder farming systems of sub-Saharan Africa. We assessed maize yield responses to nitrogen (N), phosphorus (P) and potassium (K) application and evaluated relationships between crop responses to N, P and K application and soil analysis data. Nutrient omission trials were conducted on 23 farms located in Sidindi, Western Kenya, selected to be representative of the main soil and management factors in maize based systems in Siaya County. Treatments included a control and PK, NK, NP and NPK …

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Protected Cultivation Of Vegetable Crops In Sub-Saharan Africa: Limits And Prospects For Smallholders. A Review, Thibault Nordey, Claudine Basset-Mens, Hubert De Bon, Thibaud Martin, Emilie Déletré, Serge Simon, Laurent Parrot, Hugo Despretz, Joël Huat, Yannick Biard, Thomas Dubois, Eric Malézieux Dec 2017

Protected Cultivation Of Vegetable Crops In Sub-Saharan Africa: Limits And Prospects For Smallholders. A Review, Thibault Nordey, Claudine Basset-Mens, Hubert De Bon, Thibaud Martin, Emilie Déletré, Serge Simon, Laurent Parrot, Hugo Despretz, Joël Huat, Yannick Biard, Thomas Dubois, Eric Malézieux

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Vegetable production in sub-Saharan Africa faces numerous agronomic constraints that will have to be overcome to feed the increasing population and to fight malnutrition. Technology transfer and the adoption of low-tech protected cultivation techniques affordable for smallholders are believed to be able to meet this challenge. Protected cultivation techniques are a set of agricultural practices aimed at artificializing the crop environment through the use of soil covers and/or plant covers to control pests and climatic conditions. Although protected cultivation techniques may increase the yield and quality of vegetable crops and extend their production periods worldwide, the transfer of these techniques …

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Datasets On Abundance Of Common Blossom Thrips And Weather Variables In Small-Scale Avocado Orchards At Taita Hills And Mount Kilimanjaro, James J. Odanga, Samira Mohamed, Florence Olubayo, Richard Nyankanga, Sizah Mwalusepo, Sevgan Subramanian, Tino Johansson, Sunday Ekesi Dec 2017

Datasets On Abundance Of Common Blossom Thrips And Weather Variables In Small-Scale Avocado Orchards At Taita Hills And Mount Kilimanjaro, James J. Odanga, Samira Mohamed, Florence Olubayo, Richard Nyankanga, Sizah Mwalusepo, Sevgan Subramanian, Tino Johansson, Sunday Ekesi

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Avocado, Persea americana Miller (Lauraceae), is an important fruit crop cultivated by small-holder farmers along Afrotropical highlands of Taita Hills in South-eastern Kenya and Mount Kilimanjaro in Northern Tanzania. The small-holder farmers in these East African regions generate substantial food and cash from avocado fruits. However, the avocado crop is faced with challenges of infestation by insect pests such as the common blossom thrips (Frankliniella schultzei Trybom) which feeds on pollen and floral tissue thereby reducing productivity of the trees. Moreover, there is no information describing distribution patterns of Frankliniella schultzei and associated weather in East African avocado orchards despite …

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The Cotesia Sesamiae Story: Insight Into Host-Range Evolution In A Hymenoptera Parasitoid And Implication For Its Use In Biological Control Programs, L. Kaiser, S. Dupas, A. Branca, E. A. Herniou, C. W. Clarke, C. Capdevielle Dulac, J. Obonyo, R. Benoist, J. Gauthier, P. A. Calatayud, J. F. Silvain, B. P. Le Ru Dec 2017

The Cotesia Sesamiae Story: Insight Into Host-Range Evolution In A Hymenoptera Parasitoid And Implication For Its Use In Biological Control Programs, L. Kaiser, S. Dupas, A. Branca, E. A. Herniou, C. W. Clarke, C. Capdevielle Dulac, J. Obonyo, R. Benoist, J. Gauthier, P. A. Calatayud, J. F. Silvain, B. P. Le Ru

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This review covers nearly 20 years of studies on the ecology, physiology and genetics of the Hymenoptera Cotesia sesamiae, an African parasitoid of Lepidoptera that reduces populations of common maize borers in East and South Africa. The first part of the review presents studies based on sampling of C. sesamiae from maize crops in Kenya. From this agrosystem including one host plant and three main host borer species, studies revealed two genetically differentiated populations of C. sesamiae species adapted to their local host community, and showed that their differentiation involved the joint evolution of virulence genes and sensory mechanisms of …

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Predicting Minimum Tillage Adoption Among Smallholder Farmers Using Micro-Level And Policy Variables, Paswel P. Marenya, Menale Kassie, Moti Jaleta, Dil Bahadur Rahut, Olaf Erenstein Dec 2017

Predicting Minimum Tillage Adoption Among Smallholder Farmers Using Micro-Level And Policy Variables, Paswel P. Marenya, Menale Kassie, Moti Jaleta, Dil Bahadur Rahut, Olaf Erenstein

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Minimum tillage combined with mulching (MTM) is critical to conservation agriculture, yet its use by smallholder farmers raises challenging questions regarding adoption, diffusion and scaling at farm level. In this paper, we used probit regression and post-estimation simulations to identify the key micro (farm specific) and macro (country specific) factors as predictors of MTM adoption in four countries spanning a north-south gradient in eastern and southern Africa (ESA): Ethiopia, Kenya, Tanzania and Malawi. We found that farmers’ access to markets and social capital empirically predicted MTM adoption. Policies that increased fertilizer subsidies and extension-staff-to-farmer ratios had similar effects, even if …

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Parasitic Nematode Meloidogyne Incognita Interactions With Different Capsicum Annum Cultivars Reveal The Chemical Constituents Modulating Root Herbivory, Ruth Kihika, Lucy K. Murungi, Danny Coyne, Margaret Ng'ang'a, Ahmed Hassanali, Peter E.A. Teal, Baldwyn Torto Dec 2017

Parasitic Nematode Meloidogyne Incognita Interactions With Different Capsicum Annum Cultivars Reveal The Chemical Constituents Modulating Root Herbivory, Ruth Kihika, Lucy K. Murungi, Danny Coyne, Margaret Ng'ang'a, Ahmed Hassanali, Peter E.A. Teal, Baldwyn Torto

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Plant volatile signatures are often used as cues by herbivores to locate their preferred hosts. Here, we report on the volatile organic compounds used by the subterranean root-knot nematode (RKN) Meloidogyne incognita for host location. We compared responses of infective second stage juveniles (J2s) to root volatiles of three cultivars and one accession of the solanaceous plant, Capsicum annum against moist sand in dual choice assays. J2s were more attracted to the three cultivars than to the accession, relative to controls. GC/MS analysis of the volatiles identified common constituents in each plant, five of which were identified as α-pinene, limonene, …

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Mosquito Larvicidal Activity Of Cassia Tora Seed Extract And Its Key Anthraquinones Aurantio-Obtusin And Obtusin, Valentine C. Mbatchou, David P. Tchouassi, Rita A. Dickson, Kofi Annan, Abraham Y. Mensah, Isaac K. Amponsah, Julia W. Jacob, Xavier Cheseto, Solomon Habtemariam, Baldwyn Torto Nov 2017

Mosquito Larvicidal Activity Of Cassia Tora Seed Extract And Its Key Anthraquinones Aurantio-Obtusin And Obtusin, Valentine C. Mbatchou, David P. Tchouassi, Rita A. Dickson, Kofi Annan, Abraham Y. Mensah, Isaac K. Amponsah, Julia W. Jacob, Xavier Cheseto, Solomon Habtemariam, Baldwyn Torto

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Background: The edible and medicinal leguminous plant Cassia tora L. (Fabaceae) is known to possess insecticidal properties against a wide range of plant-feeding insects. However, the bioactivity of extracts of this plant and their constituents against vectors of medical importance has been largely unexplored. We investigated the mosquito larvicidal activity of the seed extract and its major anthraquinones against larvae of the African malaria vector Anopheles gambiae (s.s.). Methods: Third-fourth instar larval mortality was observed after 24, 48, 72 and 96 h of exposure to varying doses of the extracts, and two anthraquinones isolates identified using liquid chromatography- quadrupole time …

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Infectivity Of Deinbollia Mosaic Virus, A Novel Weed-Infecting Begomovirus In East Africa, Martina Kyallo, Elijah Miinda Ateka, Peter Sseruwagi, José Trinidad Ascencio-Ibáñez, Mildred Ochwo Ssemakula, Robert Skilton, Joseph Ndunguru Nov 2017

Infectivity Of Deinbollia Mosaic Virus, A Novel Weed-Infecting Begomovirus In East Africa, Martina Kyallo, Elijah Miinda Ateka, Peter Sseruwagi, José Trinidad Ascencio-Ibáñez, Mildred Ochwo Ssemakula, Robert Skilton, Joseph Ndunguru

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Weed-infecting begomoviruses play an important role in the epidemiology of crop diseases because they can potentially infect crops and contribute to the genetic diversity of crop-infecting begomoviruses. Despite the important epidemiological role that weed-infecting begomoviruses play, they remain insufficiently studied in Africa. Recently, we identified Deinbollia mosaic virus (DMV), a distinct begomovirus found naturally infecting the weed host Deinbollia borbonica (Sapindaceae) in Kenya and Tanzania. In this study, we investigated the capacity of DMV to infect a restricted host range of Solanaceae and Euphorbiaceae species. Biolistic inoculation of Nicotiana benthamiana with concatemeric DNAs resulted in systemic infection associated with yellow …

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Protecting Cows In Small Holder Farms In East Africa From Tsetse Flies By Mimicking The Odor Profile Of A Non-Host Bovid, Rajinder K. Saini, Benedict O. Orindi, Norber Mbahin, John A. Andoke, Peter N. Muasa, David M. Mbuvi, Caroline M. Muya, John A. Pickett, Christian W. Borgemeister Oct 2017

Protecting Cows In Small Holder Farms In East Africa From Tsetse Flies By Mimicking The Odor Profile Of A Non-Host Bovid, Rajinder K. Saini, Benedict O. Orindi, Norber Mbahin, John A. Andoke, Peter N. Muasa, David M. Mbuvi, Caroline M. Muya, John A. Pickett, Christian W. Borgemeister

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Background: For the first time, differential attraction of pathogen vectors to vertebrate animals is investigated for novel repellents which when applied to preferred host animals turn them into non-hosts thereby providing a new paradigm for innovative vector control. For effectively controlling tsetse flies (Glossina spp.), vectors of African trypanosomosis, causing nagana, repellents more powerful than plant derived, from a non-host animal the waterbuck, Kobus ellipsiprymnus defassa, have recently been identified. Here we investigate these repellents in the field to protect cattle from nagana by making cattle as unattractive as the buck. Methodology/Principal findings: To dispense the waterbuck repellents comprising guaiacol, …

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Potential Distribution Dataset Of Honeybees In Indian Ocean Islands: Case Study Of Zanzibar Island, Sizah Mwalusepo, Eliud Muli, Kiatoko Nkoba, Everlyn Nguku, Joseph Kilonzo, Elfatih M. Abdel-Rahman, Tobias Landmann, Asha Fakih, Suresh Raina Oct 2017

Potential Distribution Dataset Of Honeybees In Indian Ocean Islands: Case Study Of Zanzibar Island, Sizah Mwalusepo, Eliud Muli, Kiatoko Nkoba, Everlyn Nguku, Joseph Kilonzo, Elfatih M. Abdel-Rahman, Tobias Landmann, Asha Fakih, Suresh Raina

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Honeybees (Apis mellifera) are principal insect pollinators, whose worldwide distribution and abundance is known to largely depend on climatic conditions. However, the presence records dataset on potential distribution of honeybees in Indian Ocean Islands remain less documented. Presence records in shape format and probability of occurrence of honeybees with different temperature change scenarios is provided in this article across Zanzibar Island. Maximum entropy (Maxent) package was used to analyse the potential distribution of honeybees. The dataset provides information on the current and future distribution of the honey bees in Zanzibar Island. The dataset is of great importance for improving stakeholders …

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Profitability Of Diammonium Phosphate Use In Bush And Climbing Bean-Maize Rotations In Smallholder Farms Of Central Burundi, Marie Chantal Niyuhire, Pieter Pypers, Bernard Vanlauwe, Generose Nziguheba, Dries Roobroeck, Roel Merckx Oct 2017

Profitability Of Diammonium Phosphate Use In Bush And Climbing Bean-Maize Rotations In Smallholder Farms Of Central Burundi, Marie Chantal Niyuhire, Pieter Pypers, Bernard Vanlauwe, Generose Nziguheba, Dries Roobroeck, Roel Merckx

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Soil fertility decline is a major constraint to bean (Phaseolus vulgaris L.) and maize (Zea mays) production in the Central Highlands of Burundi. Nutrient sources, specifically fertilizers, are paramount to increasing the production in the regions. Hence, improving fertilizer use efficiency is considered as a key factor towards sustainable intensification. The use of grain legumes with low harvest indices, such as climbing beans, are assumed to improve soil fertility and fertilizer use efficiency. This study compares the rotational effects of bush and climbing bean varieties on maize and evaluates the profitability of diammonium phosphate (DAP, 18–46-0) fertilizer in the bean-maize …

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Composition Of Anopheles Mosquitoes, Their Blood-Meal Hosts, And Plasmodium Falciparum Infection Rates In Three Islands With Disparate Bed Net Coverage In Lake Victoria, Kenya, Edwin Ogola, Jandouwe Villinger, Danspaid Mabuka, David Omondi, Benedict Orindi, James Mutunga, Vincent Owino, Daniel K. Masiga Sep 2017

Composition Of Anopheles Mosquitoes, Their Blood-Meal Hosts, And Plasmodium Falciparum Infection Rates In Three Islands With Disparate Bed Net Coverage In Lake Victoria, Kenya, Edwin Ogola, Jandouwe Villinger, Danspaid Mabuka, David Omondi, Benedict Orindi, James Mutunga, Vincent Owino, Daniel K. Masiga

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Background: Small islands serve as potential malaria reservoirs through which new infections might come to the mainland and may be important targets in malaria elimination efforts. This study investigated malaria vector species diversity, blood-meal hosts, Plasmodium infection rates, and long-lasting insecticidal net (LLIN) coverage on Mageta, Magare and Ngodhe Islands of Lake Victoria in western Kenya, a region where extensive vector control is implemented on the mainland. Results: From trapping for six consecutive nights per month (November 2012 to March 2015) using CDC light traps, pyrethrum spray catches and backpack aspiration, 1868 Anopheles mosquitoes were collected. Based on their cytochrome …

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Impact Of Habitat Degradation On Species Diversity And Nest Abundance Of Five African Stingless Bee Species In A Tropical Rainforest Of Kenya, Nkoba Kiatoko, Suresh Kumar Raina, Frank Van Langevelde Sep 2017

Impact Of Habitat Degradation On Species Diversity And Nest Abundance Of Five African Stingless Bee Species In A Tropical Rainforest Of Kenya, Nkoba Kiatoko, Suresh Kumar Raina, Frank Van Langevelde

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Natural habitat degradation often involves the reduction or disappearance of bee species. In Africa, stingless bees are hunted for honey, which is used as food, for medicinal purposes, and for traditional rituals. Severe habitat degradation due to human settlement is hypothesized to have a negative impact on the species diversity of the African stingless bee species. In this paper, we assess the impact of habitat degradation on the diversity of five stingless bee species across different habitats in the tropical rainforest of Kenya (indigenous forest, mixed indigenous forest) and its neighbouring landscape (grassland, village) in western Kenya. The species fauna, …

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The Impact Of Hive Type On The Behavior And Health Of Honey Bee Colonies (Apis Mellifera) In Kenya, Alexander Mcmenamin, Fiona Mumoki, Maryann Frazier, Joseph Kilonzo, Bernard Mweu, Tracey Baumgarten, Harland Patch, Baldwyn Torto, Daniel Masiga, James Tumlinson, Christina Grozinger, Elliud Muli Sep 2017

The Impact Of Hive Type On The Behavior And Health Of Honey Bee Colonies (Apis Mellifera) In Kenya, Alexander Mcmenamin, Fiona Mumoki, Maryann Frazier, Joseph Kilonzo, Bernard Mweu, Tracey Baumgarten, Harland Patch, Baldwyn Torto, Daniel Masiga, James Tumlinson, Christina Grozinger, Elliud Muli

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There has been a long-standing interest in developing approaches to maximize honey production by Kenyan beekeepers. Since honey bees in Kenya are passively managed, the main decision beekeepers make is which hive type to use: traditional Log hives, Langstroth hives, and Kenyan top-bar hives. We found Langstroth hives to be the most attractive to migrating swarms, followed by Log hives, while Kenyan top-bar hives were the least preferred. Pathogen and parasite loads correlated only with colony age and absconding rates were associated only with colony size and weight. We recommend additional studies to understand the factors that drive swarm attraction …

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