Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons™

Open Access. Powered by Scholars. Published by Universities.®

All Peer-Reviewed Publications

Discipline
Keyword
Publication Year
File Type

Articles 901 - 930 of 1443

Full-Text Articles in Life Sciences

Chemosensory Receptors In Tsetse Flies Provide Link Between Chemical And Behavioural Ecology, Daniel Masiga, George Obiero, Rosaline Macharia, Paul Mireji, Alan Christoffels Jan 2014

Chemosensory Receptors In Tsetse Flies Provide Link Between Chemical And Behavioural Ecology, Daniel Masiga, George Obiero, Rosaline Macharia, Paul Mireji, Alan Christoffels

All Peer-Reviewed Publications

Tsetse flies survive in a variety of environments across tropical Africa, often rising to large numbers, despite their low birth rate of one offspring every seven to nine days. They use olfactory receptors to process chemical signals in their environments to find food, escape from predators, and locate suitable larviposition sites. We discuss the identification of odorant and gustatory receptors in Glossina morsitans morsitans and the role genomics could play in management of nuisance insects. © 2014 Elsevier Ltd.

Go to article

Storage Of Mung Bean (Vigna Radiata [L.] Wilczek) And Pigeonpea Grains (Cajanus Cajan [L.] Millsp) In Hermetic Triple-Layer Bags Stops Losses Caused By Callosobruchus Maculatus (F.) (Coleoptera: Bruchidae), C. M. Mutungi, H. Affognon, A. W. Njoroge, D. Baributsa, L. L. Murdock Jan 2014

Storage Of Mung Bean (Vigna Radiata [L.] Wilczek) And Pigeonpea Grains (Cajanus Cajan [L.] Millsp) In Hermetic Triple-Layer Bags Stops Losses Caused By Callosobruchus Maculatus (F.) (Coleoptera: Bruchidae), C. M. Mutungi, H. Affognon, A. W. Njoroge, D. Baributsa, L. L. Murdock

All Peer-Reviewed Publications

Dry mung bean and pigeonpea grains that had sustained some insect damage but fumigated before the start of the experiment were stored in triple-layer hermetic bags (Purdue Improved Crop Storage (PICS™ bags) or woven polypropylene (PP) bags for 6 months. Some of the bags were artificially infested with cowpea bruchid Callosobruchus maculatus (F.) (PICS1, PP1) while others were not (PICS0, PP0). In an additional trial, PP bags containing the grains were treated with Actellic Super® dust before being artificially infested (PP1Ac). Moisture content, live adult C.maculatus count, grain damage, weight loss, and seed germination were determined on a monthly basis. …

Go to article

Cumulative Effects And Economic Benefits Of Intercropping Maize With Food Legumes On Striga Hermonthica Infestation, Charles A.O. Midega, Daisy Salifu, Toby J. Bruce, Jimmy Pittchar, John A. Pickett, Zeyaur R. Khan Jan 2014

Cumulative Effects And Economic Benefits Of Intercropping Maize With Food Legumes On Striga Hermonthica Infestation, Charles A.O. Midega, Daisy Salifu, Toby J. Bruce, Jimmy Pittchar, John A. Pickett, Zeyaur R. Khan

All Peer-Reviewed Publications

The parasitic weed Striga hermonthica, commonly known as striga, is a major biotic constraint to maize production in sub-Saharan Africa (SSA) where it causes serious food insecurity and poverty in smallholder farming communities. We previously discovered an effective control method for it involving intercropping cereals with fodder legumes in the genus Desmodium, commonly known as desmodium. The objectives of the current study were to evaluate cumulative effects of intercropping maize with the commonly grown food legumes on striga infestation, and to establish any economic benefits of the same. Treatments comprised maize plots planted in monocrop stands or intercropped with five …

Go to article

Aquaporins Are Critical For Provision Of Water During Lactation And Intrauterine Progeny Hydration To Maintain Tsetse Fly Reproductive Success, Joshua B. Benoit, Immo A. Hansen, Geoffrey M. Attardo, Veronika Michalková, Paul O. Mireji, Joel L. Bargul, Lisa L. Drake, Daniel K. Masiga, Serap Aksoy Jan 2014

Aquaporins Are Critical For Provision Of Water During Lactation And Intrauterine Progeny Hydration To Maintain Tsetse Fly Reproductive Success, Joshua B. Benoit, Immo A. Hansen, Geoffrey M. Attardo, Veronika Michalková, Paul O. Mireji, Joel L. Bargul, Lisa L. Drake, Daniel K. Masiga, Serap Aksoy

All Peer-Reviewed Publications

Tsetse flies undergo drastic fluctuations in their water content throughout their adult life history due to events such as blood feeding, dehydration and lactation, an essential feature of the viviparous reproductive biology of tsetse. Aquaporins (AQPs) are transmembrane proteins that allow water and other solutes to permeate through cellular membranes. Here we identify tsetse aquaporin (AQP) genes, examine their expression patterns under different physiological conditions (blood feeding, lactation and stress response) and perform functional analysis of three specific genes utilizing RNA interference (RNAi) gene silencing. Ten putative aquaporins were identified in the Glossina morsitans morsitans (Gmm) genome, two more than …

Go to article

Integrative Taxonomy Of Acrapex Stem Borers (Lepidoptera: Noctuidae: Apameini): Combining Morphology And Poisson Tree Process Analyses, Bruno P. Le Ru, Claire Capdevielle-Dulac, Emmanuel F.A. Toussaint, Desmond Conlong, Johnnie Van Den Berg, Beatrice Pallangyo, George Ong'amo, Gilson Chipabika, Richard Molo, William A. Overholt, James P. Cuda, Gael J. Kergoat Jan 2014

Integrative Taxonomy Of Acrapex Stem Borers (Lepidoptera: Noctuidae: Apameini): Combining Morphology And Poisson Tree Process Analyses, Bruno P. Le Ru, Claire Capdevielle-Dulac, Emmanuel F.A. Toussaint, Desmond Conlong, Johnnie Van Den Berg, Beatrice Pallangyo, George Ong'amo, Gilson Chipabika, Richard Molo, William A. Overholt, James P. Cuda, Gael J. Kergoat

All Peer-Reviewed Publications

Ten morphologically similar species of Acrapex from eastern and south-eastern Africa belonging to the A. stygiata and A. albivena groups are reviewed. Six species are described as new: A. brunneella, A. mitiwa, A. mpika, A. salmona, A. sporobola and A. yakoba. The Poaceae host plants of eight species are recorded; four species, A. mitiwa. A. subalbissima, A. syscia and A. yakoba, were found developing exclusively on Imperata cylindrica (L.) Beauv., (Andropogoneae); two species, A. sporobola and A. salmona, on I. cylindrica and Sporobolus macranthelus Chiov. (Zoysieae); and A. albivena on I. cylindrica, Miscanthus capensis (Nees) Andersson (Andropogoneae) and Cymbopogon sp. …

Go to article

Volatile Phytochemicals As Mosquito Semiochemicals, Vincent O. Nyasembe, Baldwyn Torto Jan 2014

Volatile Phytochemicals As Mosquito Semiochemicals, Vincent O. Nyasembe, Baldwyn Torto

All Peer-Reviewed Publications

Plant biochemical processes result in the release of an array of volatile chemical substances into the environment, some of which are known to play important plant fitness enhancing functions, such as attracting pollinators, thermal tolerance of photosynthesis, and defense against herbivores. Cunningly, phytophagous insects have evolved mechanisms to utilize these volatiles to their own advantage, either to colonize a suitable host for feeding, reproduction and oviposition or avoid an unsuitable one. The volatile compounds involved in plant-insect chemical interactions have been widely exploited in the management of agricultural pests. On the other hand, use of plant volatiles in the management …

Go to article

Laboratory Colonisation And Genetic Bottlenecks In The Tsetse Fly Glossina Pallidipes, Marc Ciosi, Daniel K. Masiga, Charles M.R. Turner Jan 2014

Laboratory Colonisation And Genetic Bottlenecks In The Tsetse Fly Glossina Pallidipes, Marc Ciosi, Daniel K. Masiga, Charles M.R. Turner

All Peer-Reviewed Publications

Background:The IAEA colony is the only one available for mass rearing of Glossina pallidipes, a vector of human and animal African trypanosomiasis in eastern Africa. This colony is the source for Sterile Insect Technique (SIT) programs in East Africa. The source population of this colony is unclear and its genetic diversity has not previously been evaluated and compared to field populations.Methodology/Principal Findings:We examined the genetic variation within and between the IAEA colony and its potential source populations in north Zimbabwe and the Kenya/Uganda border at 9 microsatellites loci to retrace the demographic history of the IAEA colony. We performed classical …

Go to article

Resistance To Iris Yellow Spot Virus And Onion Thrips Among Onion Varieties Grown In Kenya, R. K. Birithia, S. Subramanian, J. W. Muthomi, R. D. Narla Jan 2014

Resistance To Iris Yellow Spot Virus And Onion Thrips Among Onion Varieties Grown In Kenya, R. K. Birithia, S. Subramanian, J. W. Muthomi, R. D. Narla

All Peer-Reviewed Publications

Iris yellow spot virus (IYSV) vectored by Thrips tabaci threatens profitable onion production in eastern Africa. Host plant resistance is considered to be the first line of defence against insect-transmitted virus diseases. Hence, information on resistance to IYSV and T. tabaci among common onion cultivars in Kenya is crucial for the development of integrated pest management strategies. This study evaluated the resistance to thrips and IYSV among widely grown onion cultivars in Kenya, viz. Red Pinoy, Red Creole, Bombay Red, Green Bunching and Texas Grano, over two growing seasons. Straw-coloured, diamond-shaped necrotic lesions typical of IYSV infection were observed 2 …

Go to article

Whole Genome Phylogenetic Investigation Of A West Nile Virus Strain Isolated From A Tick Sampled From Livestock In North Eastern Kenya, Olivia Wesula Lwande, Marietjie Venter, Joel Lutomiah, George Michuki, Cecilia Rumberia, Francis Gakuya, Vincent Obanda, Caroline Tigoi, Collins Odhiambo, Fredrick Nindo, Samwel Symekher, Rosemary Sang Jan 2014

Whole Genome Phylogenetic Investigation Of A West Nile Virus Strain Isolated From A Tick Sampled From Livestock In North Eastern Kenya, Olivia Wesula Lwande, Marietjie Venter, Joel Lutomiah, George Michuki, Cecilia Rumberia, Francis Gakuya, Vincent Obanda, Caroline Tigoi, Collins Odhiambo, Fredrick Nindo, Samwel Symekher, Rosemary Sang

All Peer-Reviewed Publications

Background: West Nile virus (WNV) has a wide geographical distribution and has been associated to cause neurological disease in humans and horses. Mosquitoes are the traditional vectors for WNV; however, the virus has also been isolated from tick species in North Africa and Europe which could be a means of introduction and spread of the virus over long distances through migratory birds. Although WNV has been isolated in mosquitoes in Kenya, paucity of genetic and pathogenicity data exists. We previously reported the isolation of WNV from ticks collected from livestock and wildlife in Ijara District of Kenya, a hotspot for …

Go to article

Molecular Markers Reveal Narrow Genetic Base And Culturing-Associated Genetic Drift In Teretrius Nigrescens Lewis Populations Released For The Biological Control Of The Larger Grain Borer In Africa, B. A. Omondi, J. Van Den Berg, D. Masiga, F. Schulthess Jan 2014

Molecular Markers Reveal Narrow Genetic Base And Culturing-Associated Genetic Drift In Teretrius Nigrescens Lewis Populations Released For The Biological Control Of The Larger Grain Borer In Africa, B. A. Omondi, J. Van Den Berg, D. Masiga, F. Schulthess

All Peer-Reviewed Publications

In biological control, successful establishment of a natural enemy species depends on its adaptability in the introduced range including its ability to re-establish desired ecological interactions with the pest. These are affected by genetic parameters hitherto largely unresolved in biological control. The larger grain borer (LGB), Prostephanus truncatus, an invasive species from meso-America, is the most important post-harvest pest of maize in Africa. We studied the genetic structure of Teretrius nigrescens, a predatory beetle previously released for the control of the pest in Africa, to test the hypothesis that establishment patterns were a result of ecotype-environment mismatch and to follow …

Go to article

Scattered Shade Trees Improve Low-Input Smallholder Arabica Coffee Productivity In The Northern Lake Kivu Region Of Rwanda, F. Pinard, J. M. Boffa, E. Rwakagara Jan 2014

Scattered Shade Trees Improve Low-Input Smallholder Arabica Coffee Productivity In The Northern Lake Kivu Region Of Rwanda, F. Pinard, J. M. Boffa, E. Rwakagara

All Peer-Reviewed Publications

In suboptimal conditions for coffee growth, the use of shade tree is usually considered beneficial to production. This study aimed to evaluate this benefit in the poorly documented East African smallholder Arabica coffee systems in optimal climatic but suboptimal management conditions. In a 4 year observational trial in 50 coffee farms, the association of shade trees and coffee generated an average 55 % cherry production increase. Neither delay in berry maturation nor buffer in alternate bearing patterns were observed, probably due to the low productivity of unfertilized coffee plants. Quality wise, the presence of shade trees did not result in …

Go to article

Effects Of Anticancer Drug Docetaxel On The Structure And Function Of The Rabbit Olfactory Mucosa, Boniface M. Kavoi, Johanna Plendl, Andrew N. Makanya, Shem Ochieng', Stephen G. Kiama Jan 2014

Effects Of Anticancer Drug Docetaxel On The Structure And Function Of The Rabbit Olfactory Mucosa, Boniface M. Kavoi, Johanna Plendl, Andrew N. Makanya, Shem Ochieng', Stephen G. Kiama

All Peer-Reviewed Publications

Docetaxel (DCT) is an anticancer drug which acts by disrupting microtubule dynamics in the highly mitotic cancer cells. Thus, this drug has a potential to affect function and organization of tissues exhibiting high cellular turnover. We investigated, in the rabbit, the effects of a single human equivalent dose (6.26. mg/kg, i.v.) of DCT on the olfactory mucosa (OM) through light and electron microscopy, morphometry, Ki-67 immunostaining, TUNEL assay and the buried food test for olfactory sensitivity. On post-exposure days (PED) 5 and 10, there was disarrangement of the normal cell layering in the olfactory epithelium (OE), apoptotic death of cells …

Go to article

Integrated Decision Support For Sustainable And Profitable Land Management In The Lowlands Of Central Asia, Nodir Djanibekov, Rolf Sommer Jan 2014

Integrated Decision Support For Sustainable And Profitable Land Management In The Lowlands Of Central Asia, Nodir Djanibekov, Rolf Sommer

All Peer-Reviewed Publications

Land use and crop production in the Khorezm region in western Uzbekistan, exemplarily for the irrigated lowlands of Central Asia, are challenged by the excessive, non-sustainable use of irrigation water and repeated water shortages on one hand, and soil degradation by secondary salinization on the other hand. One of the research objectives of the German-Uzbek Khorezm project, funded by the German Ministry for Education and Research (BMBF) and led by Center of Development Research (ZEF) of Bonn University, was to better understand options for land use and choice of technology at the farm level in order to evaluate and propose …

Go to article

Biology Of The Coconut Bug, Pseudotheraptus Wayi, On French Beans, James Peter Egonyu, Sunday Ekesi, Jacques Kabaru, Lucy Irungu Jan 2014

Biology Of The Coconut Bug, Pseudotheraptus Wayi, On French Beans, James Peter Egonyu, Sunday Ekesi, Jacques Kabaru, Lucy Irungu

All Peer-Reviewed Publications

The coconut bug, Pseudotheraptus wayi Brown (Heteroptera: Coreidae), is a major pest of a wide range of economically important crops in Eastern and Southern Africa. The suitability of French beans, Phaseolus vulgaris L. (Fabales: Fabaceae) as an alternative food for mass rearing of P. wayi was determined by elucidating its development, survival, and reproduction on French bean pods in the laboratory. Development and survival of immatures on French beans was comparable to what is reported with two hosts previously used for rearing this species, namely coconut and cashew. Adults survived thrice longer and laid almost twice more eggs on the …

Go to article

Triple Bag Hermetic Storage Delivers A Lethal Punch To Prostephanus Truncatus (Horn) (Coleoptera: Bostrichidae) In Stored Maize, A. W. Njoroge, H. D. Affognon, C. M. Mutungi, J. Manono, P. O. Lamuka, L. L. Murdock Jan 2014

Triple Bag Hermetic Storage Delivers A Lethal Punch To Prostephanus Truncatus (Horn) (Coleoptera: Bostrichidae) In Stored Maize, A. W. Njoroge, H. D. Affognon, C. M. Mutungi, J. Manono, P. O. Lamuka, L. L. Murdock

All Peer-Reviewed Publications

Clean shelled maize was stored in woven polypropylene (PP) or triple layer polyethylene (PICS™) bags in the presence of Prostephanus truncatus Horn (PP1; PICS1) or absence of it (PP0; PICS0) at ambient conditions for six months. Moisture content, live insect population, grain damage, weight loss, and germination were analyzed on a monthly basis. Temperature and relative humidity in both PICS- and PP-bag setups were monitored, as well as the oxygen and carbon dioxide levels in the PICS bags. Overall, maize stored in PICS bags had significantly lower (P<0.05) moisture content than maize stored in PP bags. Storage in PICS bag slowed growth of P.truncatus populations and blocked infestation from the surrounding storage environment. On the contrary, PP bags permitted profuse build-up of insect population and cross-infestation. At six months, grain damage was 0.0%, 3.4%, 50.5% and 73.9%, corresponding to weight loss of 0.0%, 2.0%, 36.3%, and 47.7% in PICS0, PICS1, PP0 and PP1, respectively. Germination of maize stored in PP bags dropped from 91.1% to 37.0% and 12.7% in PP0 and PP1, respectively, whereas germination of maize stored in PICS bags dropped only marginally and reached 78.1% and 71.0% in PICS0 and PICS1, respectively, in six months. Without extreme loss of grain viability, a huge decrease in insect infestation, grain damage and weight loss is achieved by storing maize in PICS bag even under P.truncatus endemic conditions. © 2014 Elsevier Ltd.

Go to article

Odorant And Gustatory Receptors In The Tsetse Fly Glossina Morsitans Morsitans, George F.O. Obiero, Paul O. Mireji, Steven R.G. Nyanjom, Alan Christoffels, Hugh M. Robertson, Daniel K. Masiga Jan 2014

Odorant And Gustatory Receptors In The Tsetse Fly Glossina Morsitans Morsitans, George F.O. Obiero, Paul O. Mireji, Steven R.G. Nyanjom, Alan Christoffels, Hugh M. Robertson, Daniel K. Masiga

All Peer-Reviewed Publications

Tsetse flies use olfactory and gustatory responses, through odorant and gustatory receptors (ORs and GRs), to interact with their environment. Glossina morsitans morsitans genome ORs and GRs were annotated using homologs of these genes in Drosophila melanogaster and an ab initio approach based on OR and GR specific motifs in G. m. morsitans gene models coupled to gene ontology (GO). Phylogenetic relationships among the ORs or GRs and the homologs were determined using Maximum Likelihood estimates. Relative expression levels among the G. m. morsitans ORs or GRs were established using RNA-seq data derived from adult female fly. Overall, 46 and …

Go to article

Evaluation Of Acaricide-Treated String Curtains For Control Of Two-Spotted Spider Mite Tetranychus Urticae Koch (Acari: Tetranychidae) On Greenhouse Roses And Impact Of The String Curtain On The Predatory Mite Phytoseiulus Persimilis Athias-Henriot (Acari: Phytoseiidae), Emilie M. Deletre, Romain Bonafos, Thibaud Martin Jan 2014

Evaluation Of Acaricide-Treated String Curtains For Control Of Two-Spotted Spider Mite Tetranychus Urticae Koch (Acari: Tetranychidae) On Greenhouse Roses And Impact Of The String Curtain On The Predatory Mite Phytoseiulus Persimilis Athias-Henriot (Acari: Phytoseiidae), Emilie M. Deletre, Romain Bonafos, Thibaud Martin

All Peer-Reviewed Publications

Foliar sprays of pesticides are frequently used to control two-spotted mites on rose flowers, but these also destroy predatory mites and pose a high risk of contamination for humans and the environment. Using a novel approach to avoid spray applications on rose plants, modified acaricide-treated string curtains were adapted to control the pest. Two main aims of this study were: (i) to identify the lethal concentration of string curtains treated with propargite, dicofol, flufenoxuron, acrinathrin or tau-fluvalinate (τ-fluvalinate) on Tetranychus urticae, and (ii) to test the design (feasibility) and efficiency of the string curtains to trap the phytophagous mites on …

Go to article

Integrated Soil Fertility Management: Aggregate Carbon And Nitrogen Stabilization In Differently Textured Tropical Soils, R. M. Gentile, B. Vanlauwe, J. Six Dec 2013

Integrated Soil Fertility Management: Aggregate Carbon And Nitrogen Stabilization In Differently Textured Tropical Soils, R. M. Gentile, B. Vanlauwe, J. Six

All Peer-Reviewed Publications

Soil organic matter is important to improve and sustain soil fertility in tropical agroecosystems. The combined use of organic residue and fertilizer inputs is advocated for its positive effects on short-term nutrient supply, but the effect of the integrated use on long-term stabilization of soil organic C and N is still unclear. We conducted a 1.5-y soil incubation experiment with maize (Zea mays) residue and urea fertilizer to examine the stabilization of C and N in four Sub-Saharan African soils differing in texture (sand, sandy loam, clay loam, and clay). The inputs were enriched with 13C and 15N in a …

Go to article

Comparative Diagnostic And Analytical Performance Of Pcr And Lamp-Based Trypanosome Detection Methods Estimated Using Pooled Whole Tsetse Flies And Midguts, Imna I. Malele, Johnson O. Ouma, John C.K. Enyaru, Enock Matovu, Vincent Alibu, Joanna E. Auma, Samuel G. Onyoyo, Rosemary Bateta, Robert E. Changasi, Phoebe W. Mukiria, Kariuki Ndung'u, Purity K. Gitonga, Lilian M. Mwaniki, Hamisi S. Nyingilili, Eugene A. Lyaruu, Lupakisyo A. Kapange, Peter Kuria Kamau, Daniel K. Masiga Oct 2013

Comparative Diagnostic And Analytical Performance Of Pcr And Lamp-Based Trypanosome Detection Methods Estimated Using Pooled Whole Tsetse Flies And Midguts, Imna I. Malele, Johnson O. Ouma, John C.K. Enyaru, Enock Matovu, Vincent Alibu, Joanna E. Auma, Samuel G. Onyoyo, Rosemary Bateta, Robert E. Changasi, Phoebe W. Mukiria, Kariuki Ndung'u, Purity K. Gitonga, Lilian M. Mwaniki, Hamisi S. Nyingilili, Eugene A. Lyaruu, Lupakisyo A. Kapange, Peter Kuria Kamau, Daniel K. Masiga

All Peer-Reviewed Publications

Detection of trypanosomes that cause disease in human beings and livestock within their tsetse fly hosts is an essential component of vector and disease control programmes. Several molecular-based diagnostic tests have been developed for this purpose. Many of these tests, while sensitive, require analysis of trypanosome DNA extracted from single flies, or from pooled tsetse fly heads and amplified trypanosome DNA. In this study, we evaluated the relative analytical and diagnostic sensitivities of two PCR-based tests (ITS and TBR) and a Trypanozoon specific LAMP assay using pooled whole tsetse flies and midguts spiked with serially diluted procyclics of a laboratory …

Go to article

Differential Attractiveness Of Human Foot Odours To Anopheles Gambiae Giles Sensu Stricto (Diptera: Culicidae) And Variation In Their Chemical Composition, M. O. Omolo, B. Njiru, I. O. Ndiege, R. M. Musau, A. Hassanali Oct 2013

Differential Attractiveness Of Human Foot Odours To Anopheles Gambiae Giles Sensu Stricto (Diptera: Culicidae) And Variation In Their Chemical Composition, M. O. Omolo, B. Njiru, I. O. Ndiege, R. M. Musau, A. Hassanali

All Peer-Reviewed Publications

Counter flow geometry (CFG) traps (American Biophysics) baited with foot odours (adsorbed overnight on a combination of a nylon and a cotton socks) from 4 groups of 4 male volunteers were initially used in a screen-house to compare and grade the attractiveness of Anopheles gambiae Giles sensu stricto to these odours. Ten individuals were then selected from the 4 groups for further grading in which mosquito attractiveness to odours adsorbed on socks worn by each of the individuals was compared against a control (clean, un-worn cotton and nylon socks). A gradation of attractiveness was found, with the most attractive foot …

Go to article

Coffee Berry Borer Joins Bark Beetles In Coffee Klatch, Juliana Jaramillo, Baldwyn Torto, Dickson Mwenda, Armin Troeger, Christian Borgemeister, Hans Michael Poehling, Wittko Francke Sep 2013

Coffee Berry Borer Joins Bark Beetles In Coffee Klatch, Juliana Jaramillo, Baldwyn Torto, Dickson Mwenda, Armin Troeger, Christian Borgemeister, Hans Michael Poehling, Wittko Francke

All Peer-Reviewed Publications

Unanswered key questions in bark beetle-plant interactions concern host finding in species attacking angiosperms in tropical zones and whether management strategies based on chemical signaling used for their conifer-attacking temperate relatives may also be applied in the tropics. We hypothesized that there should be a common link in chemical signaling mediating host location by these Scolytids. Using laboratory behavioral assays and chemical analysis we demonstrate that the yellow-orange exocarp stage of coffee berries, which attracts the coffee berry borer, releases relatively high amounts of volatiles including conophthorin, chalcogran, frontalin and sulcatone that are typically associated with Scolytinae chemical ecology. The …

Go to article

Seasonal Abundance Of Western Flower Thrips And Its Natural Enemies In Different French Bean Agroecosystems In Kenya, J. O. Nyasani, R. Meyhöfer, S. Subramanian, H. M. Poehling Sep 2013

Seasonal Abundance Of Western Flower Thrips And Its Natural Enemies In Different French Bean Agroecosystems In Kenya, J. O. Nyasani, R. Meyhöfer, S. Subramanian, H. M. Poehling

All Peer-Reviewed Publications

The seasonal abundance of western flower thrips (WFT) [Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)] and its natural enemies on French beans in two agro-ecological zones (AEZs) (high and mid altitude) in Kenya, was studied in three growing cycles from January to December 2009. French beans were sampled every 2 weeks for WFT and natural enemies. Results show that colonization of French beans with WFT in both farm scales studied in the two AEZs started at 2- to 3-leaf stage. There was an increase in the population density of WFT from budding stage to podding/flowering stage, and it declined at crop senescence. …

Go to article

Phosphorus Agronomic Efficiency In Maize-Based Cropping Systems: A Focus On Western Kenya, J. Kihara, S. Njoroge Aug 2013

Phosphorus Agronomic Efficiency In Maize-Based Cropping Systems: A Focus On Western Kenya, J. Kihara, S. Njoroge

All Peer-Reviewed Publications

Phosphorus (P) is facing a quantity and quality supply issue and increasing its use efficiency is important for its continued use and profitability in crop production. The objective of this study was to determine how agronomic efficiency of P (PAE) in different environments and management systems in western Kenya is affected by N application, inherent soil fertility and organic resources. We used data constituting over 2700 data points from 126 farm fields of 25 different studies conducted from 1996 to 2009. Potassium (K) deficiency is negligible in western Kenya while ommission of P and N result in a 50% and …

Go to article

Effect Of Leaf Type And Pesticide Exposure On Abundance Of Bacterial Taxa In Mosquito Larval Habitats, Ephantus J. Muturi, Benedict O. Orindi, Chang Hyun Kim Aug 2013

Effect Of Leaf Type And Pesticide Exposure On Abundance Of Bacterial Taxa In Mosquito Larval Habitats, Ephantus J. Muturi, Benedict O. Orindi, Chang Hyun Kim

All Peer-Reviewed Publications

Lentic freshwater systems including those inhabited by aquatic stages of mosquitoes derive most of their carbon inputs from terrestrial organic matter mainly leaf litter. The leaf litter is colonized by microbial communities that provide the resource base for mosquito larvae. While the microbial biomass associated with different leaf species in container aquatic habitats is well documented, the taxonomic composition of these microbes and their response to common environmental stressors is poorly understood. We used indoor aquatic microcosms to determine the abundances of major taxonomic groups of bacteria in leaf litters from seven plant species and their responses to low concentrations …

Go to article

Endophytic Colonization Of Vicia Faba And Phaseolus Vulgaris (Fabaceae) By Fungal Pathogens And Their Effects On The Life-History Parameters Of Liriomyza Huidobrensis (Diptera: Agromyzidae), K. S. Akutse, N. K. Maniania, K. K.M. Fiaboe, J. Van Den Berg, S. Ekesi Aug 2013

Endophytic Colonization Of Vicia Faba And Phaseolus Vulgaris (Fabaceae) By Fungal Pathogens And Their Effects On The Life-History Parameters Of Liriomyza Huidobrensis (Diptera: Agromyzidae), K. S. Akutse, N. K. Maniania, K. K.M. Fiaboe, J. Van Den Berg, S. Ekesi

All Peer-Reviewed Publications

Ten fungal isolates belonging to the genera Beauveria (3), Hypocrea (1), Gibberella (1), Metarhizium (2), Trichoderma (1) and Fusarium (2) were evaluated in the laboratory to determine whether they could become endophytic in two pea leafminer (Liriomyza huidobrensis) host plants (Vicia faba and Phaseolus vulgaris), and to assess their possible negative effects on leafminers. Beauveria (ICIPE279), Hypocrea, Gibberella, Fusarium and Trichoderma isolates colonized roots, stems and leaves of both host plant species. Beauveria isolates G1LU3 and S4SU1 colonized roots, stems, and leaves of P. vulgaris but only the root and stem of V. faba. Isolates of Metarhizium failed to colonize …

Go to article

Gene Expression-Based Biomarkers For Anopheles Gambiae Age Grading, Mei Hui Wang, Osvaldo Marinotti, Daibin Zhong, Anthony A. James, Edward Walker, Tom Guda, Eliningaya J. Kweka, John Githure, Guiyun Yan Jul 2013

Gene Expression-Based Biomarkers For Anopheles Gambiae Age Grading, Mei Hui Wang, Osvaldo Marinotti, Daibin Zhong, Anthony A. James, Edward Walker, Tom Guda, Eliningaya J. Kweka, John Githure, Guiyun Yan

All Peer-Reviewed Publications

Information on population age structure of mosquitoes under natural conditions is fundamental to the understanding of vectorial capacity and crucial for assessing the impact of vector control measures on malaria transmission. Transcriptional profiling has been proposed as a method for predicting mosquito age for Aedes and Anopheles mosquitoes, however, whether this new method is adequate for natural conditions is unknown. This study tests the applicability of transcriptional profiling for age-grading of Anopheles gambiae, the most important malaria vector in Africa. The transcript abundance of two An. gambiae genes, AGAP009551 and AGAP011615, was measured during aging under laboratory and field conditions …

Go to article

Dominant Inheritance Of Field-Evolved Resistance To Bt Corn In Busseola Fusca, Pascal Campagne, Marlene Kruger, Rémy Pasquet, Bruno Le Ru, Johnnie Van Den Berg Jul 2013

Dominant Inheritance Of Field-Evolved Resistance To Bt Corn In Busseola Fusca, Pascal Campagne, Marlene Kruger, Rémy Pasquet, Bruno Le Ru, Johnnie Van Den Berg

All Peer-Reviewed Publications

Transgenic crops expressing Bacillus thuringiensis (Bt) toxins have been adopted worldwide, notably in developing countries. In spite of their success in controlling target pests while allowing a substantial reduction of insecticide use, the sustainable control of these pest populations is threatened by the evolution of resistance. The implementation of the "high dose/refuge" strategy for managing insect resistance in transgenic crops aims at delaying the evolution of resistance to Bt crops in pest populations by promoting survival of susceptible insects. However, a crucial condition for the "high dose/refuge" strategy to be efficient is that the inheritance of resistance should be functionally …

Go to article

Candidate Chemosensory Genes In The Stemborer Sesamia Nonagrioides, Nicolas Glaser, Aurore Gallot, Fabrice Legeai, Nicolas Montagné, Erwan Poivet, Myriam Harry, Paul André Calatayud, Emmanuelle Jacquin-Joly Jun 2013

Candidate Chemosensory Genes In The Stemborer Sesamia Nonagrioides, Nicolas Glaser, Aurore Gallot, Fabrice Legeai, Nicolas Montagné, Erwan Poivet, Myriam Harry, Paul André Calatayud, Emmanuelle Jacquin-Joly

All Peer-Reviewed Publications

The stemborer Sesamia nonagrioides is an important pest of maize in the Mediterranean Basin. Like other moths, this noctuid uses its chemosensory system to efficiently interact with its environment. However, very little is known on the molecular mechanisms that underlie chemosensation in this species. Here, we used next-generation sequencing (454 and Illumina) on different tissues from adult and larvae, including chemosensory organs and female ovipositors, to describe the chemosensory transcriptome of S. nonagrioides and identify key molecular components of the pheromone production and detection systems. We identified a total of 68 candidate chemosensory genes in this species, including 31 candidate …

Go to article

Horizontal Transmission Of Metarhizium Anisopliae In Fruit Flies And Effect Of Fungal Infection On Egg Laying And Fertility, Susan Dimbi, Nguya K. Maniania, Sunday Ekesi Jun 2013

Horizontal Transmission Of Metarhizium Anisopliae In Fruit Flies And Effect Of Fungal Infection On Egg Laying And Fertility, Susan Dimbi, Nguya K. Maniania, Sunday Ekesi

All Peer-Reviewed Publications

Fly-to-fly transmission of conidia of the entomopathogenic fungus Metarhizium anisopliae and the effect of fungal infection on the reproductive potential of females surviving infection were investigated in three fruit fly species, Ceratitis cosyra, C. fasciventris, and C. capitata. The number of conidia picked up by a single fruit fly was determined in C. cosyra. The initial uptake (Day 0) of conidia by a single fly was approx. 1.1 × 106 conidia after exposure to the treated substrate. However, the number of conidia dropped from 7.2 × 105 to 4.1 × 105 conidia after 2 and 8 h post-exposure, respectively. The …

Go to article

Pushing The Envelope? Maize Production Intensification And The Role Of Cattle Manure In Recovery Of Degraded Soils In Smallholder Farming Areas Of Zimbabwe, Leonard Rusinamhodzi, Marc Corbeels, Shamie Zingore, Justice Nyamangara, Ken E. Giller Jun 2013

Pushing The Envelope? Maize Production Intensification And The Role Of Cattle Manure In Recovery Of Degraded Soils In Smallholder Farming Areas Of Zimbabwe, Leonard Rusinamhodzi, Marc Corbeels, Shamie Zingore, Justice Nyamangara, Ken E. Giller

All Peer-Reviewed Publications

Soil fertility decline is a major constraint to crop productivity on smallholder farms in Africa. The objective of this study was to evaluate the long-term (up to nine years) impacts of nutrient management strategies and their local feasibility on crop productivity, soil fertility status and rainfall infiltration on two contrasting soil types and different prior management regimes in Murehwa, Zimbabwe. The nutrient management strategies employed in the study were: a control with no fertiliser, amendments of 100kg Nha-1, 100kg N+lime, three rates of manure application (5, 15 and 25tha-1) in combination with 100kg Nha-1, and three rates of P fertiliser …

Go to article

First Prev Next Last