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Articles 601 - 630 of 1443

Full-Text Articles in Life Sciences

A Multiplex Assay For The Sensitive Detection And Quantification Of Male And Female Plasmodium Falciparum Gametocytes, Lisette Meerstein-Kessel, Chiara Andolina, Elvira Carrio, Almahamoudou Mahamar, Patrick Sawa, Halimatou Diawara, Marga Van De Vegte-Bolmer, Will Stone, Katharine A. Collins, Petra Schneider, Alassane Dicko, Chris Drakeley, Ingrid Felger, Till Voss, Kjerstin Lanke, Teun Bousema Nov 2018

A Multiplex Assay For The Sensitive Detection And Quantification Of Male And Female Plasmodium Falciparum Gametocytes, Lisette Meerstein-Kessel, Chiara Andolina, Elvira Carrio, Almahamoudou Mahamar, Patrick Sawa, Halimatou Diawara, Marga Van De Vegte-Bolmer, Will Stone, Katharine A. Collins, Petra Schneider, Alassane Dicko, Chris Drakeley, Ingrid Felger, Till Voss, Kjerstin Lanke, Teun Bousema

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Background: The transmission of malaria to mosquitoes depends on the presence of gametocytes that circulate in the peripheral blood of infected human hosts. Sensitive estimates of the densities of female gametocytes (FG) and male gametocytes (MG) may allow the prediction of infectivity to mosquitoes and thus a molecular estimate of the human infectious reservoir for transmission. Methods: A novel multiplex qRT-PCR assay with intron-spanning primers was developed for the parallel quantification of FG and MG. CCp4 (PF3D7-0903800) transcripts specific for FG and PfMGET (PF3D7-1469900) transcripts specific for MG were quantified in total nucleic acids. The assay was validated on sex-sorted …

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Sodalis Glossinidius Presence In Wild Tsetse Is Only Associated With Presence Of Trypanosomes In Complex Interactions With Other Tsetse-Specific Factors 06 Biological Sciences 0604 Genetics, Manun Channumsin, Marc Ciosi, Dan Masiga, C. Michael R. Turner, Barbara K. Mable Nov 2018

Sodalis Glossinidius Presence In Wild Tsetse Is Only Associated With Presence Of Trypanosomes In Complex Interactions With Other Tsetse-Specific Factors 06 Biological Sciences 0604 Genetics, Manun Channumsin, Marc Ciosi, Dan Masiga, C. Michael R. Turner, Barbara K. Mable

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Background: Susceptibility of tsetse flies (Glossina spp.) to trypanosomes of both humans and animals has been associated with the presence of the endosymbiont Sodalis glossinidius. However, intrinsic biological characteristics of the flies and environmental factors can influence the presence of both S. glossinidius and the parasites. It thus remains unclear whether it is the S. glossinidius or other attributes of the flies that explains the apparent association. The objective of this study was to test whether the presence of Trypanosoma vivax, T. congolense and T. brucei are related to the presence of S. glossinidius in tsetse flies when other factors …

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Enhancing Vector Refractoriness To Trypanosome Infection: Achievements, Challenges And Perspectives, Henry M. Kariithi, Irene K. Meki, Daniela I. Schneider, Linda De Vooght, Fathiya M. Khamis, Anne Geiger, Guler Demirbaş-Uzel, Just M. Vlak, Ikbal Agah Ince, Sorge Kelm, Flobert Njiokou, Florence N. Wamwiri, Imna I. Malele, Brian L. Weiss, Adly M.M. Abd-Alla Nov 2018

Enhancing Vector Refractoriness To Trypanosome Infection: Achievements, Challenges And Perspectives, Henry M. Kariithi, Irene K. Meki, Daniela I. Schneider, Linda De Vooght, Fathiya M. Khamis, Anne Geiger, Guler Demirbaş-Uzel, Just M. Vlak, Ikbal Agah Ince, Sorge Kelm, Flobert Njiokou, Florence N. Wamwiri, Imna I. Malele, Brian L. Weiss, Adly M.M. Abd-Alla

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With the absence of effective prophylactic vaccines and drugs against African trypanosomosis, control of this group of zoonotic neglected tropical diseases depends the control of the tsetse fly vector. When applied in an area-wide insect pest management approach, the sterile insect technique (SIT) is effective in eliminating single tsetse species from isolated populations. The need to enhance the effectiveness of SIT led to the concept of investigating tsetse-trypanosome interactions by a consortium of researchers in a five-year (2013-2018) Coordinated Research Project (CRP) organized by the Joint Division of FAO/IAEA. The goal of this CRP was to elucidate tsetse-symbiome-pathogen molecular interactions …

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Vertical Transmission Of Naturally Occurring Bunyamwera And Insect-Specific Flavivirus Infections In Mosquitoes From Islands And Mainland Shores Of Lakes Victoria And Baringo In Kenya, Yvonne Ukamaka Ajamma, Thomas Ogao Onchuru, Daniel O. Ouso, David Omondi, Daniel K. Masiga, Jandouwe Villinger Nov 2018

Vertical Transmission Of Naturally Occurring Bunyamwera And Insect-Specific Flavivirus Infections In Mosquitoes From Islands And Mainland Shores Of Lakes Victoria And Baringo In Kenya, Yvonne Ukamaka Ajamma, Thomas Ogao Onchuru, Daniel O. Ouso, David Omondi, Daniel K. Masiga, Jandouwe Villinger

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Background: Many arboviruses transmitted by mosquitoes have been implicated as causative agents of both human and animal illnesses in East Africa. Although epidemics of arboviral emerging infectious diseases have risen in frequency in recent years, the extent to which mosquitoes maintain pathogens in circulation during inter-epidemic periods is still poorly understood. This study aimed to investigate whether arboviruses may be maintained by vertical transmission via immature life stages of different mosquito vector species. Methodology: We collected immature mosquitoes (egg, larva, pupa) on the shores and islands of Lake Baringo and Lake Victoria in western Kenya and reared them to adults. …

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Threshold Temperatures And Thermal Requirements Of Black Soldier Fly Hermetia Illucens: Implications For Mass Production, Shaphan Yong Chia, Chrysantus Mbi Tanga, Fathiya M. Khamis, Samira A. Mohamed, Daisy Salifu, Subramanian Sevgan, Komi K.M. Fiaboe, Saliou Niassy, Joop J.A. Van Loon, Marcel Dicke, Sunday Ekesi Nov 2018

Threshold Temperatures And Thermal Requirements Of Black Soldier Fly Hermetia Illucens: Implications For Mass Production, Shaphan Yong Chia, Chrysantus Mbi Tanga, Fathiya M. Khamis, Samira A. Mohamed, Daisy Salifu, Subramanian Sevgan, Komi K.M. Fiaboe, Saliou Niassy, Joop J.A. Van Loon, Marcel Dicke, Sunday Ekesi

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Efforts to recycle organic wastes using black soldier fly (BSF) Hermetia illucens into highnutrient biomass that constitutes a sustainable fat (biodiesel) and high-quality protein ingredient in animal feeds have recently gained momentum worldwide. However, there is little information on the most suitable rearing conditions for growth, development and survivorship of these flies, which is a prerequisite for mass production technologies. We evaluated the physiological requirements for growth and reproduction of H. illucens on two diets [spent grains supplemented with brewers' yeast (D1) and un-supplemented (D2)]. Development rates at nine constant temperatures (10-42°C) were fitted to temperature-dependent linear and non-linear day-degree …

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Influence Of Feeding-Damaged Plants On The Oviposition Responses Within A Community Of Female Moths, Eric Siaw Ntiri, Paul Andre Calatayud, Boaz Musyoka, Johnnie Van Den Berg, Bruno Pierre Le Ru Nov 2018

Influence Of Feeding-Damaged Plants On The Oviposition Responses Within A Community Of Female Moths, Eric Siaw Ntiri, Paul Andre Calatayud, Boaz Musyoka, Johnnie Van Den Berg, Bruno Pierre Le Ru

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Competitive or facilitative interactions characterise phytophagous insect communities that utilise the same resources. These interactions are often mediated by the host plant. Plant mediation influences the oviposition choices that a community of insects, sharing the same host plant make. In this context, the oviposition choices of females within a community of lepidopteran cereal stemborers namely Busseola fusca, Sesamia calamistis and Chilo partellus were studied in plant choice-experiments under laboratory and field conditions. Gravid females of each species were presented with a choice between maize plants infested by conspecific or heterospecific larvae and uninfested maize plants. The number of eggs and …

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Α-Amylase Mediates Host Acceptance In The Braconid Parasitoid Cotesia Flavipes, Gladys Bichang’A, Jean Luc Da Lage, Claire Capdevielle-Dulac, Michel Zivy, Thierry Balliau, Kevin Sambai, Bruno Le Ru, Laure Kaiser, Gerald Juma, Esther Njoki Mwangi Maina, Paul André Calatayud Nov 2018

Α-Amylase Mediates Host Acceptance In The Braconid Parasitoid Cotesia Flavipes, Gladys Bichang’A, Jean Luc Da Lage, Claire Capdevielle-Dulac, Michel Zivy, Thierry Balliau, Kevin Sambai, Bruno Le Ru, Laure Kaiser, Gerald Juma, Esther Njoki Mwangi Maina, Paul André Calatayud

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Foraging parasitoids use chemical signals in host recognition and selection processes. Although, the volatiles play a relevant role in the localization by parasitoids of their hosts feeding on plants, the host identification process for acceptance occurs mainly during contact between the parasitoid and its host where host products related to feeding activities, fecal pellets and oral secretions, play a crucial role. The purpose of this study was to identify the nature of the contact kairomone(s) that mediate the acceptance for oviposition of the parasitoid Cotesia flavipes Cameron (Hymenoptera, Braconidae), which was released in Kenya in 1993 to control the invasive …

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Response Of Common Bean (Phaseolus Vulgaris L.) To Nitrogen, Phosphorus And Rhizobia Inoculation Across Variable Soils In Zimbabwe, Vongai Chekanai, Regis Chikowo, Bernard Vanlauwe Nov 2018

Response Of Common Bean (Phaseolus Vulgaris L.) To Nitrogen, Phosphorus And Rhizobia Inoculation Across Variable Soils In Zimbabwe, Vongai Chekanai, Regis Chikowo, Bernard Vanlauwe

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Common bean is an important crop with potential to curb malnutrition in poor Sub-Saharan African populations. Yields of common bean (Phaseolus vulgaris L.) are, however poor, limited by low soil phosphorus (P), nitrogen (N) and poor biological N2-fixation. On-farm experiments were carried out to study the effect of N, P and rhizobia inoculation on common bean yield and yield components during the 2014/2015 and 2015/2016 cropping seasons in Eastern Zimbabwe. Experiments were conducted on five farmers’ fields located in two agroecologies; three fields were considered to be degraded with soil organic carbon (SOC) < 4 g kg−1 and available P < 6 mg kg−1, while the two non–degraded sites had SOC > 7 g kg−1 and available P > 15 …

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Vector Competence Of Aedes Bromeliae And Aedes Vitattus Mosquito Populations From Kenya For Chikungunya Virus, Francis Mulwa, Joel Lutomiah, Edith Chepkorir, Samwel Okello, Fredrick Eyase, Caroline Tigoi, Michael Kahato, Rosemary Sang Oct 2018

Vector Competence Of Aedes Bromeliae And Aedes Vitattus Mosquito Populations From Kenya For Chikungunya Virus, Francis Mulwa, Joel Lutomiah, Edith Chepkorir, Samwel Okello, Fredrick Eyase, Caroline Tigoi, Michael Kahato, Rosemary Sang

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Background: Kenya has experienced outbreaks of chikungunya in the past years with the most recent outbreak occurring in Mandera in the northern region in May 2016 and in Mombasa in the coastal region from November 2017 to February 2018. Despite the outbreaks in Kenya, studies on vector competence have only been conducted on Aedes aegypti. However, the role played by other mosquito species in transmission and maintenance of the virus in endemic areas remains unclear. This study sought to determine the possible role of rural Aedes bromeliae and Aedes vittatus in the transmission of chikungunya virus, focusing on Kilifi and …

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Detection Of Pesticide Residues In Selected Bee Products Of Honeybees (Apis Melllifera L.) Colonies In A Preliminary Study From Seychelles Archipelago, Elliud Muli, Joseph Kilonzo, Norman Dogley, Gerald Monthy, Justus Kurgat, Janet Irungu, Suresh Raina Oct 2018

Detection Of Pesticide Residues In Selected Bee Products Of Honeybees (Apis Melllifera L.) Colonies In A Preliminary Study From Seychelles Archipelago, Elliud Muli, Joseph Kilonzo, Norman Dogley, Gerald Monthy, Justus Kurgat, Janet Irungu, Suresh Raina

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Pesticide residues in honey and pollen from Seychelles against a target of 108 pesticides using LC-MS/MS were analyzed. Fifteen pesticides were detected, at trace levels (< 15 ppb) and below the acceptable maximum residue limits (MRLs) as per EU regulations. In honey, six insecticide and three fungicide residues were detected. Eight insecticide and four fungicide residues were detected in the pollen matrix. The least contaminated honey and pollen samples had three and nine chemical residues respectively while the most contaminated honey and pollen samples had eight and eleven chemical residues respectively. Contact and oral LD50 values were used to calculate Pollen Hazard Quotients (PHQ) = concentration in ppb ÷ LD50 as µg/bee. The pollen hazard quotients (PHQ) obtained are way below those reported in literature. Residues were detected in low quantities, however, their high frequency and diversity and possible synergistic interactions may lead to negative impact on honeybees’ health in Seychelles.

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A Scientifc Note On Validation Of Housekeeping Genes For The Primitively Eusocial Bee Euglossa Viridissima Friese (Apidae: Euglossini), S. Boff, A. Friedel, A. Miertsch, J. J.G. Quezada-Euán, R. J. Paxton, H. M.G. Lattorff Oct 2018

A Scientifc Note On Validation Of Housekeeping Genes For The Primitively Eusocial Bee Euglossa Viridissima Friese (Apidae: Euglossini), S. Boff, A. Friedel, A. Miertsch, J. J.G. Quezada-Euán, R. J. Paxton, H. M.G. Lattorff

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Studies on the expression of genes in different contexts are essential to our understanding of the functioning of organisms and their adaptations to the environment. Gene expression studies require steps of normalization, which are done using the stable expression pattern of reference genes. For many different eusocial bees reference genes have been discovered, but not for the primitively eusocial Euglossini bees. We used available genomic resources of Euglossini species and the gene information of Apis mellifera Linnaeus to develop a set of reference genes for the primitive eusocial bee Euglossa viridissima Friese. We tested nine genes, in distinct developmental stages, …

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Screening For Resistance Against Major Lepidopteran And Stem Weevil Pests Of Amaranth In Tanzania, S. T.O. Othim, R. Srinivasan, R. Kahuthia-Gathu, T. Dubois, F. F. Dinssa, S. Ekesi, K. K.M. Fiaboe Oct 2018

Screening For Resistance Against Major Lepidopteran And Stem Weevil Pests Of Amaranth In Tanzania, S. T.O. Othim, R. Srinivasan, R. Kahuthia-Gathu, T. Dubois, F. F. Dinssa, S. Ekesi, K. K.M. Fiaboe

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Insect pests pose major challenges to optimum productivity of amaranth in Africa and Asia. The use of insecticides is the main control strategy, but is expensive and may pose health and environmental concerns, especially if proper care is not taken. Host plant resistance offers a cheap and sustainable pest management alternative. Open field experiments were conducted during two cropping seasons in 2016 and 2017 to screen 35 amaranth accessions and lines for resistance to leaf-webbers and stem weevils. The diversity (H) of lepidopteran defoliators and their parasitoids on each accession ranged from 0.00 to 1.57 and 0.00 to 1.65, respectively …

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Gene Expression Profiles Of Odorant Binding Proteins In Glossina Brevipalpis (Diptera: Glossinidae), Mary Murithi, Rosaline Macharia, Esther Magiri, Steven Nyanjom, Daniel Masiga Oct 2018

Gene Expression Profiles Of Odorant Binding Proteins In Glossina Brevipalpis (Diptera: Glossinidae), Mary Murithi, Rosaline Macharia, Esther Magiri, Steven Nyanjom, Daniel Masiga

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Glossina spp. (Diptera: Glossinidae) vector trypanosomes, the causal pathogens of trypanosomiasis in humans and animals. Glossina spp. chemosensory mechanism is relevant to understanding the behavioral responses of these insects to environmental cues. Odorant binding proteins (OBPs) are involved in either olfactory or nonolfactory cue sensation depending on their spatial and temporal expression. In most insects, the OBPs are ubiquitously expressed, although the levels are higher in the antennae. This study was aimed at determining the differential gene expression patterns of OBP genes in the developmental stages (larval, pupal, teneral) and differentially starved adults of Glossina brevipalpis (Newstead) collected from Shimba …

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Transcriptomics Reveal Potential Vaccine Antigens And A Drastic Increase Of Upregulated Genes During Theileria Parva Development From Arthropod To Bovine Infective Stages, Triza Tonui, Pilar Corredor-Moreno, Esther Kanduma, Joyce Njuguna, Moses N. Njahira, Steven G. Nyanjom, Joana C. Silva, Appolinaire Djikeng, Roger Pelle Oct 2018

Transcriptomics Reveal Potential Vaccine Antigens And A Drastic Increase Of Upregulated Genes During Theileria Parva Development From Arthropod To Bovine Infective Stages, Triza Tonui, Pilar Corredor-Moreno, Esther Kanduma, Joyce Njuguna, Moses N. Njahira, Steven G. Nyanjom, Joana C. Silva, Appolinaire Djikeng, Roger Pelle

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Theileria parva is a protozoan parasite transmitted by the brown ear tick Rhipicephalus appendiculatus that causes East Coast fever (ECF) in cattle, resulting in substantial economic losses in the regions of southern, eastern and central Africa. The schizont form of the parasite transforms the bovine host lymphocytes into actively proliferating cancer-like cells. However, how T. parva causes bovine host cells to proliferate and maintain a cancerous phenotype following infection is still poorly understood. On the other hand, current efforts to develop improved vaccines have identified only a few candidate antigens. In the present paper, we report the first comparative transcriptomic …

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Sustainably Improving Kenya's Coffee Production Needs More Participation Of Younger Farmers With Diversified Income, Lydia W.I. Wairegi, Mica Bennett, Generose Nziguheba, Ashiraf Mawanda, Carlos De Los Rios, Edidah Ampaire, Laurence Jassogne, Pamela Pali, David Mukasa, Piet J.A. Van Asten Oct 2018

Sustainably Improving Kenya's Coffee Production Needs More Participation Of Younger Farmers With Diversified Income, Lydia W.I. Wairegi, Mica Bennett, Generose Nziguheba, Ashiraf Mawanda, Carlos De Los Rios, Edidah Ampaire, Laurence Jassogne, Pamela Pali, David Mukasa, Piet J.A. Van Asten

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Kenya's Arabica coffee is highly rated in the world and is a major source of income for over half a million smallholder farmers. Production has declined by 50% over the past 25 years despite efforts by initiatives. This study tries to unravel what drives coffee production in Kenya. Data were collected on six cooperatives through household interviews and discussions with farmers, cooperative officials, and key informants. Yields ranged from ten to 3889 kg/ha/year, averaged 474 kg/ha/year and were positively correlated with intensity of crop management (r = 0.09, P < 0.05). Coffee represented about 25–50% of total household income. The oldest farmers (average 63 years) were poorer, had less diversified income sources and managed coffee less intensively than younger farmers. Intensity of management differed among cooperatives and was positively correlated with trust in the cooperative (r = 0.209, P < 0.001). Households that received credit from marketers were 30% more likely to use fertilizers than other households. We show that the yield gap can be closed by existing practices, and intensification is influenced by household characteristics and services received. We conclude that increasing the participation of young farmers in coffee production and creating an enabling environment for intensification can have a positive and sustainable effect on national production.

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The Occurrence, Diversity And Blood Feeding Patterns Of Potential Vectors Of Dengue And Yellow Fever In Kacheliba, West Pokot County, Kenya, E. Chepkorir, M. Venter, J. Lutomiah, F. Mulwa, S. Arum, D. P. Tchouassi, R. Sang Oct 2018

The Occurrence, Diversity And Blood Feeding Patterns Of Potential Vectors Of Dengue And Yellow Fever In Kacheliba, West Pokot County, Kenya, E. Chepkorir, M. Venter, J. Lutomiah, F. Mulwa, S. Arum, D. P. Tchouassi, R. Sang

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Introduction: Yellow fever (YF) and dengue (DEN) viruses are important re-emerging mosquito-borne viruses sharing similar vectors and reservoirs. The last documented YF outbreak in Kenya occurred in 1992–95. However, YF virus is re-emerging in bordering countries including Uganda, Ethiopia and South Sudan with the potential for spread to the neighboring regions in Kenya. Dengue is endemic in Kenya with outbreaks being detected in various towns in the north and the coast. This study reports on the Aedes (Stegomyia) mosquito species occurrence, diversity, and blood feeding patterns, as means of measuring the risk of transmission of YF and DEN in Kacheliba …

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Diversity And Distribution Of Lepidopteran Stemborer Species And Their Host Plants In Botswana, Eva Moeng, Reyard Mutamiswa, Des E. Conlong, Yoseph Assefa, Bruno P. Le Ru, Muluken Goftishu, Casper Nyamukondiwa Oct 2018

Diversity And Distribution Of Lepidopteran Stemborer Species And Their Host Plants In Botswana, Eva Moeng, Reyard Mutamiswa, Des E. Conlong, Yoseph Assefa, Bruno P. Le Ru, Muluken Goftishu, Casper Nyamukondiwa

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Lepidopteran stemborers are amongst the most important insect pests of maize, sorghum and sugarcane in sub-Saharan Africa. With the exception of Chilo partellus (Swinhoe), which was accidentally introduced into Africa, the other stemborer pests are indigenous to the continent and have co-evolved with native grasses and sedges. In addition to pest species, wild habitats harbour diverse non-economic stemborer species, some of which are new to science. However, the diversity and distribution of both non-economic and pest species of stemborer are currently mostly unknown in Botswana. Accordingly, country-wide surveys were conducted during 2014/15 and 2015/16 austral summer to determine species diversity …

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Lateral Eyes Direct Principal Eyes As Jumping Spiders Track Objects, Elizabeth M. Jakob, Skye M. Long, Duane P. Harland, Robert R. Jackson, Ashley Carey, Mary Emma Searles, Adam H. Porter, Cristina Canavesi, Jannick P. Rolland Sep 2018

Lateral Eyes Direct Principal Eyes As Jumping Spiders Track Objects, Elizabeth M. Jakob, Skye M. Long, Duane P. Harland, Robert R. Jackson, Ashley Carey, Mary Emma Searles, Adam H. Porter, Cristina Canavesi, Jannick P. Rolland

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One way of circumventing the functional tradeoffs on eye design [1,2] is to have different eyes for different tasks. For example, jumping spiders (Salticidae), known for elaborate, visually guided courtship and predatory behavior [3], view the same object simultaneously with two of their four pairs of eyes: the antero-lateral eyes (ALEs) and the principal eyes (reviewed in [2]; Figure 1A). The ALEs, with immobile lenses and retinas, wide fields of view, and hyperacute sensitivity to moving stimuli [4], are structurally distinct from the principal eyes, which have the best spatial acuity known for terrestrial invertebrates and can discern fine details …

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Endophytic Effects Of Aspergillus Oryzae On Radish (Raphanus Sativus) And Its Herbivore, Plutella Xylostella, Bo Tong Sun, Komivi Senyo Akutse, Xiao Feng Xia, Jun Hui Chen, Xin Ai, Yang Tang, Qian Wang, Bo Wen Feng, Mark S. Goettel, Min Sheng You Sep 2018

Endophytic Effects Of Aspergillus Oryzae On Radish (Raphanus Sativus) And Its Herbivore, Plutella Xylostella, Bo Tong Sun, Komivi Senyo Akutse, Xiao Feng Xia, Jun Hui Chen, Xin Ai, Yang Tang, Qian Wang, Bo Wen Feng, Mark S. Goettel, Min Sheng You

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Main conclusion: We provide evidence that Aspergillus oryzae not only acts as an endophyte in Raphanus sativus, but also works as a plant growth promoter and provides some protection against its herbivore, Plutella xylostella affecting its feeding rate, mortality and fitness parameters, thereby contributing to the pest population suppression. Seed inoculation of radish seeds with the fungus Aspergillus oryzae allowed its establishment as an endophyte promoting plant growth and negatively affecting fitness parameters of its major herbivore, diamondback moth, Plutella xylostella. Endophytic fungi may contribute to the growth of their host plants and enhance resistance to herbivores and diseases. We …

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Push–Pull Farming System In Kenya: Implications For Economic And Social Welfare, Menale Kassie, Jesper Stage, Gracious Diiro, Beatrice Muriithi, Geoffrey Muricho, Samuel T. Ledermann, Jimmy Pittchar, Charles Midega, Kahn Zeyaur Sep 2018

Push–Pull Farming System In Kenya: Implications For Economic And Social Welfare, Menale Kassie, Jesper Stage, Gracious Diiro, Beatrice Muriithi, Geoffrey Muricho, Samuel T. Ledermann, Jimmy Pittchar, Charles Midega, Kahn Zeyaur

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This study examines the farm-level economic benefits and aggregate welfare impacts of adopting push–pull technology (PPT)—an innovative, integrated pest and soil-fertility management strategy—with a set of household- and plot-level data collected in western Kenya. The evaluation is based on a combination of econometric and economic surplus analysis. Treatment effect estimates are used to assess the technology-induced shift in the maize supply curve, which is then used as an input to the economic surplus analysis. Finally, the aggregate poverty impact is computed using the economic surplus estimates. We observe that the adoption of PPT led to significant increases in maize yield …

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Effects Of Flower Thrips (Thysanoptera: Thripidae) On Nutritional Quality Of Banana (Zingiberales: Musaceae) Buds, Deyi Yu, Peng Huang, Yong Chen, Yongwen Lin, Komivi Senyo Akutse, Yanyang Lan, Hui Wei Aug 2018

Effects Of Flower Thrips (Thysanoptera: Thripidae) On Nutritional Quality Of Banana (Zingiberales: Musaceae) Buds, Deyi Yu, Peng Huang, Yong Chen, Yongwen Lin, Komivi Senyo Akutse, Yanyang Lan, Hui Wei

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The abundance of banana flower thrips (Thrips hawaiiensis Morgan) in a banana (Musa acuminata Colla "Williams" cultivar) plantation was investigated using yellow sticky traps (29.70 cm × 21.00 cm) in 2015. Banana flower thrips occurred throughout the year with monthly variation, and the maximum occurrence was observed in October and November during the bud burst (73.80 ± 6.32 adults/trap) and young fruit (70.06 ± 5.69 adults/trap) periods. The damage rates were as follows: interior flowers >3rd-layer flowers > 2nd-layer flowers > 1st-layer flowers > young fruits. This result indicates that thrips migrated to lower bracts, young fruits, and other flower buds as bracts …

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Maize Chlorotic Mottle Virus Induces Changes In Host Plant Volatiles That Attract Vector Thrips Species, Nelson L. Mwando, Amanuel Tamiru, Johnson O. Nyasani, Meshack A.O. Obonyo, John C. Caulfield, Toby J.A. Bruce, Sevgan Subramanian Aug 2018

Maize Chlorotic Mottle Virus Induces Changes In Host Plant Volatiles That Attract Vector Thrips Species, Nelson L. Mwando, Amanuel Tamiru, Johnson O. Nyasani, Meshack A.O. Obonyo, John C. Caulfield, Toby J.A. Bruce, Sevgan Subramanian

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Maize lethal necrosis is one of the most devastating diseases of maize causing yield losses reaching up to 90% in sub-Saharan Africa. The disease is caused by a combination of maize chlorotic mottle virus (MCMV) and any one of cereal viruses in the Potyviridae group such as sugarcane mosaic virus. MCMV has been reported to be transmitted mainly by maize thrips (Frankliniella williamsi) and onion thrips (Thrips tabaci). To better understand the role of thrips vectors in the epidemiology of the disease, we investigated behavioral responses of F. williamsi and T. tabaci, to volatiles collected from maize seedlings infected with …

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Varroa-Specific Hygienic Behavior Of Apis Mellifera Scutellata In Kenya, Sammy Kiprotich Cheruiyot, H. Michael G. Lattorff, Ruth Kahuthia-Gathu, Jenard Patrick Mbugi, Elliud Muli Aug 2018

Varroa-Specific Hygienic Behavior Of Apis Mellifera Scutellata In Kenya, Sammy Kiprotich Cheruiyot, H. Michael G. Lattorff, Ruth Kahuthia-Gathu, Jenard Patrick Mbugi, Elliud Muli

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Varroa-specific hygienic behavior is a hereditary trait of honey bee (Apis mellifera), which supports resistance to Varroa destructor. This study investigated the response of Apis mellifera scutellata to Varroa-infested worker brood cells in Kenya, East Africa. Uncapping, removal of the brood, and disappearance of the introduced mite were recorded in a total of 690 cells into which live mites were introduced. We recorded a high proportion of untouched cells in controls (median, 80%) compared to manipulated cells in which mites had been introduced (median, 12.5%) with a significant difference (GLMM, p < 0.001). Mites were removed and cells were recapped in about 26% of the artificially infested brood cells. When ten, eight, and five mites were singly introduced in closely neighboring brood cells, hygienic bees were more responsive in the high mite density regime of eight and ten mites, an indication of a possibility that chemicals play a role in identification of Varroa-infested brood cells.

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Genotypic Response Of Brachiaria (Urochloa Spp.) To Spider Mite (Oligonychus Trichardti) (Acari: Tetranychidae) And Adaptability To Different Environments, Duncan Cheruiyot, Charles A.O. Midega, Edward A. Ueckermann, Johnnie Van Den Berg, John A. Pickett, Zeyaur R. Khan Aug 2018

Genotypic Response Of Brachiaria (Urochloa Spp.) To Spider Mite (Oligonychus Trichardti) (Acari: Tetranychidae) And Adaptability To Different Environments, Duncan Cheruiyot, Charles A.O. Midega, Edward A. Ueckermann, Johnnie Van Den Berg, John A. Pickett, Zeyaur R. Khan

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Grasses in the genus Urochloa, commonly known as brachiaria, are grown as forage crops in sub-Saharan Africa, with some genotypes being used in management of insect pests. However, spider mite, Oligonychus trichardti Meyer (Acari: Tetranychidae), has recently been reported as its major pest in the region. We evaluated 18 brachiaria genotypes to identify sources of resistance to O. trichardti, and to determine their adaptability to different environments in western Kenya. Response to artificial infestation with O. trichardti was evaluated under controlled conditions in a screenhouse while adaptability to different environments and field resistance to mites was evaluated in three locations …

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Integrated Soil Fertility Management Sequences For Reducing Climate Risk In Smallholder Crop Production Systems In Southern Africa, Hatirarami Nezomba, Florence Mtambanengwe, Jairos Rurinda, Paul Mapfumo Jul 2018

Integrated Soil Fertility Management Sequences For Reducing Climate Risk In Smallholder Crop Production Systems In Southern Africa, Hatirarami Nezomba, Florence Mtambanengwe, Jairos Rurinda, Paul Mapfumo

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Climate change, increased climate variability and poor soil fertility are major bio-physical constraints to cropping on smallholder farms in southern Africa. We used the Agricultural Production Systems sIMulator (APSIM) to assess maize yield response to integrated soil fertility management (ISFM) rotational sequences of low-quality organic resources, nitrogen-fixing green manure and grain legumes, and mineral fertilizers under baseline (1960–2005) and projected (2040–2069) climates. APSIM was also employed to evaluate the response of maize yield to the ISFM sequences under a combination of a changing climate, and typical sowing dates and mineral fertilizer application rates for smallholder households of varying resource endowment. …

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Cowpea (Vigna Unguiculata L. Walp) Hosts Several Widespread Bradyrhizobial Root Nodule Symbionts Across Contrasting Agro-Ecological Production Areas In Kenya, Samuel Mathu Ndungu, Monika M. Messmer, Dominik Ziegler, Hannes A. Gamper, Éva Mészáros, Moses Thuita, Bernard Vanlauwe, Emmanuel Frossard, Cécile Thonar Jul 2018

Cowpea (Vigna Unguiculata L. Walp) Hosts Several Widespread Bradyrhizobial Root Nodule Symbionts Across Contrasting Agro-Ecological Production Areas In Kenya, Samuel Mathu Ndungu, Monika M. Messmer, Dominik Ziegler, Hannes A. Gamper, Éva Mészáros, Moses Thuita, Bernard Vanlauwe, Emmanuel Frossard, Cécile Thonar

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Cowpea (Vigna unguiculata L. Walp.) is an important African food legume suitable for dry regions. It is the main legume in two contrasting agro-ecological regions of Kenya as an important component of crop rotations because of its relative tolerance to unpredictable drought events. This study was carried out in an effort to establish a collection of bacterial root nodule symbionts and determine their relationship to physicochemical soil parameters as well as any geographical distributional patterns. Bradyrhizobium spp. were found to be widespread in this study and several different types could be identified at each site. Unique but rare symbionts were …

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Sustainable Intensification Through Rotations With Grain Legumes In Sub-Saharan Africa: A Review, A. C. Franke, G. J. Van Den Brand, B. Vanlauwe, K. E. Giller Jul 2018

Sustainable Intensification Through Rotations With Grain Legumes In Sub-Saharan Africa: A Review, A. C. Franke, G. J. Van Den Brand, B. Vanlauwe, K. E. Giller

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We conducted a systematic review of literature on the residual effects of grain legumes in cereal-based systems of sub-Saharan Africa (SSA) to quantify the magnitude and variability of rotational effects, to explore the importance of environmental and management factors in determining variability and to evaluate the evidence of the different mechanisms that explain rotational effects. We retrieved 44 unique publications providing 199 observations comparing continuous cereal performance with that of a grain legume-cereal rotation. The overall mean yield increase of 0.49 t grain ha−1, equal to an increase of 41% of the continuous cereal yield, is highly significant, but the …

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Spatial Distribution Of Bactrocera Dorsalis And Thaumatotibia Leucotreta In Smallholder Avocado Orchards Along Altitudinal Gradient Of Taita Hills And Mount Kilimanjaro, James J. Odanga, Samira Mohamed, Sizah Mwalusepo, Florence Olubayo, Richard Nyankanga, Fathiya Khamis, Ivan Rwomushana, Tino Johansson, Sunday Ekesi Jun 2018

Spatial Distribution Of Bactrocera Dorsalis And Thaumatotibia Leucotreta In Smallholder Avocado Orchards Along Altitudinal Gradient Of Taita Hills And Mount Kilimanjaro, James J. Odanga, Samira Mohamed, Sizah Mwalusepo, Florence Olubayo, Richard Nyankanga, Fathiya Khamis, Ivan Rwomushana, Tino Johansson, Sunday Ekesi

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Avocado (Persea americana) fruits are an important source of income and a nutritious food for small-scale growers and other stakeholders involved in farming along the Afrotropical highlands of Taita Hills and Mount Kilimanjaro in Kenya and Tanzania, respectively. Avocado fruits are infested by several insect pests, namely the Asian invasive fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), and the false codling moth, Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortricidae). However, there is inadequate information on the distribution patterns of these pests in small-scale avocado cropping systems in the East African highlands. This study was initiated to generate a spatial distribution map of …

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Expression Of Resistance In Amaranthus Spp. (Caryophyllales: Amaranthaceae): Effects Of Selected Accessions On The Behaviour And Biology Of The Amaranth Leaf-Webber, Spoladea Recurvalis (Lepidoptera: Crambidae), Stephen T.O. Othim, Srinivasan Ramasamy, Ruth Kahuthia-Gathu, Thomas Dubois, Sunday Ekesi, Komi K.M. Fiaboe Jun 2018

Expression Of Resistance In Amaranthus Spp. (Caryophyllales: Amaranthaceae): Effects Of Selected Accessions On The Behaviour And Biology Of The Amaranth Leaf-Webber, Spoladea Recurvalis (Lepidoptera: Crambidae), Stephen T.O. Othim, Srinivasan Ramasamy, Ruth Kahuthia-Gathu, Thomas Dubois, Sunday Ekesi, Komi K.M. Fiaboe

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Spoladea recurvalis F. is a major pest moth of amaranth (Amaranthus spp.) flowers worldwide, with a potential of causing complete foliage loss under severe outbreaks. Chemical insecticides are uneconomical for resource-poor farmers and pose health and environmental risks. Host plant resistance (HPR) to insects is an effective, economical and environmentally friendly alternative that is poorly understood and largely unexploited among traditional leafy vegetables. A total of 35 amaranth accessions were evaluated for the expression of their antixenotic and antibiotic traits against S. recurvalis, focusing on their effects on the biology of the pest in comparison with a susceptible accession. The …

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Prediction Of Insect Pest Distribution As Influenced By Elevation: Combining Field Observations And Temperature-Dependent Development Models For The Coffee Stink Bug, Antestiopsis Thunbergii (Gmelin), Abdelmutalab G.A. Azrag, Christian W.W. Pirk, Abdullahi A. Yusuf, Fabrice Pinard, Saliou Niassy, Gladys Mosomtai, Régis Babin Jun 2018

Prediction Of Insect Pest Distribution As Influenced By Elevation: Combining Field Observations And Temperature-Dependent Development Models For The Coffee Stink Bug, Antestiopsis Thunbergii (Gmelin), Abdelmutalab G.A. Azrag, Christian W.W. Pirk, Abdullahi A. Yusuf, Fabrice Pinard, Saliou Niassy, Gladys Mosomtai, Régis Babin

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The antestia bug, Antestiopsis thunbergii (Gmelin 1790) is a major pest of Arabica coffee in Africa. The bug prefers coffee at the highest elevations, contrary to other major pests. The objectives of this study were to describe the relationship between A. thunbergii populations and elevation, to elucidate this relationship using our knowledge of the pest thermal biology and to predict the pest distribution under climate warming. Antestiopsis thunbergii population density was assessed in 24 coffee farms located along a transect delimited across an elevation gradient in the range 1000–1700 m asl, on Mt. Kilimanjaro, Tanzania. Density was assessed for three …

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