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International Centre of Insect Physiology and Ecology

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Articles 91 - 120 of 147

Full-Text Articles in Animal Sciences

Sheep Skin Odor Improves Trap Captures Of Mosquito Vectors Of Rift Valley Fever, David P. Tchouassi, Rosemary Sang, Catherine L. Sole, Armanda D.S. Bastos, Klaus Mithoefer, Baldwyn Torto Nov 2012

Sheep Skin Odor Improves Trap Captures Of Mosquito Vectors Of Rift Valley Fever, David P. Tchouassi, Rosemary Sang, Catherine L. Sole, Armanda D.S. Bastos, Klaus Mithoefer, Baldwyn Torto

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In recent years, the East African region has seen an increase in arboviral diseases transmitted by blood-feeding arthropods. Effective surveillance to monitor and reduce incidence of these infections requires the use of appropriate vector sampling tools. Here, trapped skin volatiles on fur from sheep, a known preferred host of mosquito vectors of Rift Valley fever virus (RVFV), were used with a standard CDC light trap to improve catches of mosquito vectors. We tested the standard CDC light trap alone (L), and baited with (a) CO2 (LC), (b) animal volatiles (LF), and (c) CO2 plus animal volatiles (LCF) in two highly …

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Genetic Structure And Mating System Of Wild Cowpea Populations In West Africa, Eric B. Kouam, Remy S. Pasquet, Pascal Campagne, Jean Baptiste Tignegre, Kevin Thoen, Remi Gaudin, Jeremy T. Ouedraogo, Abdulai B. Salifu, Geoffrey M. Muluvi, Paul Gepts Jul 2012

Genetic Structure And Mating System Of Wild Cowpea Populations In West Africa, Eric B. Kouam, Remy S. Pasquet, Pascal Campagne, Jean Baptiste Tignegre, Kevin Thoen, Remi Gaudin, Jeremy T. Ouedraogo, Abdulai B. Salifu, Geoffrey M. Muluvi, Paul Gepts

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Background: Cowpea is a highly inbred crop. It is part of a crop-weed complex, whose origin and dynamics is unknown, which is distributed across the African continent. This study examined outcrossing rates and genetic structures in 35 wild cowpea (Vigna unguiculata ssp. unguiculata var. spontanea) populations from West Africa, using 21 isozyme loci, 9 of them showing polymorphism.Results: Outcrossing rates ranged from 1% to 9.5% (mean 3.4%), which classifies the wild cowpea breeding system as primarily selfing, though rare outcrossing events were detected in each population studied. Furthermore, the analyses of both the genetic structure of populations and the relationships …

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Attending To Detail By Communal Spider-Eating Spiders, Robert R. Jackson, Ximena J. Nelson Jul 2012

Attending To Detail By Communal Spider-Eating Spiders, Robert R. Jackson, Ximena J. Nelson

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Communal predators may often need to make especially intricate foraging decisions, as a predator's success may depend on the actions of its neighbours. Here, we consider the decisions made by Portia africana, a jumping spider (Salticidae) that preys on other spiders, including Oecobius amboseli (Oecobiidae), a small prey spider that lives under small sheets of silk (nests) on the walls of buildings. P. africana juveniles settle near oecobiid nests and then ambush oecobiids as they leave or enter the nest. Two or more P. africana juveniles sometimes settle at the same nest and, when an oecobiid is captured, the P. …

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Ethnoknowledge Of Bukusu Community On Livestock Tick Prevention And Control In Bungoma District, Western Kenya, Wycliffe Wanzala, Willem Takken, Wolfgang R. Mukabana, Achola O. Pala, Ahmed Hassanali Mar 2012

Ethnoknowledge Of Bukusu Community On Livestock Tick Prevention And Control In Bungoma District, Western Kenya, Wycliffe Wanzala, Willem Takken, Wolfgang R. Mukabana, Achola O. Pala, Ahmed Hassanali

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Ethnopharmacological relevance: To date, nomadic communities in Africa have been the primary focus of ethnoveterinary research. The Bukusu of western Kenya have an interesting history, with nomadic lifestyle in the past before settling down to either arable or mixed arable/pastoral farming systems. Their collective and accumulative ethnoveterinary knowledge is likely to be just as rich and worth documenting. Aim of the study: The aim of the present study was to document indigenous knowledge of the Bukusu on the effect of livestock ticks and ethnopractices associated with their management. It was envisaged that this would provide a basis for further research …

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Exploitation Of Environmental Noise By An Araneophagic Assassin Bug, Anne E. Wignall, Robert R. Jackson, R. Stimson Wilcox, Phillip W. Taylor Nov 2011

Exploitation Of Environmental Noise By An Araneophagic Assassin Bug, Anne E. Wignall, Robert R. Jackson, R. Stimson Wilcox, Phillip W. Taylor

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Predatory arthropods that specialize in invading webs and preying on the resident spiders ('araneophagic predators') face special challenges. As webs are exceedingly good at transmitting vibrations, it is difficult for a web invader to move through the web and remain undetected by the spider. An araneophagic predator that generates vibrations in the web may risk prey escaping or even counterattacking. To increase the chances of an undetected approach, predators may exploit episodes of environmental noise to approach, while their prey's ability to detect them is compromised ('opportunistic smokescreen behaviour'). Here we provide the first experimental evidence of convergent opportunistic smokescreen …

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Reliance On Trial And Error Signal Derivation By Portia Africana, An Araneophagic Jumping Spider From East Africa, Robert R. Jackson, Ximena J. Nelson May 2011

Reliance On Trial And Error Signal Derivation By Portia Africana, An Araneophagic Jumping Spider From East Africa, Robert R. Jackson, Ximena J. Nelson

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All species from the jumping spider (Salticidae) genus Portia appear to be predators that specialize at preying on other spiders by invading webs and, through aggressive mimicry, gaining dynamic fine control over the resident spider's behavior. From previous research, there is evidence that P. fimbriata, P. labiata and P. schultzi derive signals by trial and error. Here, we demonstrate that P. africana is another species that uses a trial and error, or generate and test, algorithm when deriving the aggressive-mimicry signals that will be appropriate in different predator-prey encounters. We discuss the implications of these new findings and the findings …

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Construction Of A Ssr-Based Genetic Map And Identification Of Qtl For Domestication Traits Using Recombinant Inbred Lines From A Cross Between Wild And Cultivated Cowpea (V. Unguiculata (L.) Walp.), Mebeaselassie Andargie, Remy S. Pasquet, Bhavani S. Gowda, Geoffrey M. Muluvi, Michael P. Timko Jan 2011

Construction Of A Ssr-Based Genetic Map And Identification Of Qtl For Domestication Traits Using Recombinant Inbred Lines From A Cross Between Wild And Cultivated Cowpea (V. Unguiculata (L.) Walp.), Mebeaselassie Andargie, Remy S. Pasquet, Bhavani S. Gowda, Geoffrey M. Muluvi, Michael P. Timko

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Cowpea (Vigna unguiculata (L.) Walp.) is a grain legume commonly grown and consumed in many parts of the tropics and subtropics. A genetic linkage map was constructed using simple sequence repeat (SSR) markers and a recombinant inbred (RI) population of159 individuals derived from a cross between the breeding line 524B, a California Blackeye, and 219-01, a perennial wild cowpea from Kenya. Out of 912 primer combinations predicted to amplify SSRs in cowpea, 639 reliably produced amplification products in PCR assays and 202 (31.6%) were polymorphic between the two parents. These polymorphic SSRs were used to construct a genetic map consisting …

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Repellent Activity Of Catmint, Nepeta Cataria, And Iridoid Nepetalactone Isomers Against Afro-Tropical Mosquitoes, Ixodid Ticks And Red Poultry Mites, Michael A. Birkett, Ahmed Hassanali, Solveig Hoglund, Jan Pettersson, John A. Pickett Jan 2011

Repellent Activity Of Catmint, Nepeta Cataria, And Iridoid Nepetalactone Isomers Against Afro-Tropical Mosquitoes, Ixodid Ticks And Red Poultry Mites, Michael A. Birkett, Ahmed Hassanali, Solveig Hoglund, Jan Pettersson, John A. Pickett

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The repellent activity of the essential oil of the catmint plant, Nepeta cataria (Lamiaceae), and the main iridoid compounds (4aS,7S,7aR) and (4aS,7S,7aS)-nepetalactone, was assessed against (i) major Afro-tropical pathogen vector mosquitoes, i.e. The malaria mosquito, Anopheles gambiae s.s. and the Southern house mosquito, Culex quinquefasciatus, using a World Health Organisation (WHO)-approved topical application bioassay (ii) the brown ear tick, Rhipicephalus appendiculatus, using a climbing repellency assay, and (iii) the red poultry mite, Dermanyssus gallinae, using field trapping experiments. Gas chromatography (GC) and coupled GC-mass spectrometry (GC-MS) analysis of two N. cataria chemotypes (A and B) used in the repellency assays …

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Chemical Ecology Of Animal And Human Pathogen Vectors In A Changing Global Climate, John A. Pickett, Michael A. Birkett, Sarah Y. Dewhirst, James G. Logan, Maurice O. Omolo, Baldwyn Torto, Julien Pelletier, Zainulabeuddin Syed, Walter S. Leal Feb 2010

Chemical Ecology Of Animal And Human Pathogen Vectors In A Changing Global Climate, John A. Pickett, Michael A. Birkett, Sarah Y. Dewhirst, James G. Logan, Maurice O. Omolo, Baldwyn Torto, Julien Pelletier, Zainulabeuddin Syed, Walter S. Leal

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Infectious diseases affecting livestock and human health that involve vector-borne pathogens are a global problem, unrestricted by borders or boundaries, which may be exacerbated by changing global climate. Thus, the availability of effective tools for control of pathogen vectors is of the utmost importance. The aim of this article is to review, selectively, current knowledge of the chemical ecology of pathogen vectors that affect livestock and human health in the developed and developing world, based on key note lectures presented in a symposium on "The Chemical Ecology of Disease Vectors" at the 25th Annual ISCE meeting in Neuchatel, Switzerland. The …

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Geographic And Breed Distribution Patterns Of An A/G Polymorphism Present In The Mx Gene Suggests Balanced Selection In Village Chickens, S. Ommeh, L. N. Jin, H. Eding, F. C. Muchadeyi, S. Sulandari, M. S.A. Zein, G. Danbaro, C. E. Wani, S. G. Zhao, Q. H. Nie, X. Q. Zhang, M. Ndila, R. Preisinger, G. H. Chen, I. A. Yousif, K. N. Heo, S. J. Oh, M. Tapio, D. Masiga, O. Hanotte, H. Jianlin, S. Weigend Jan 2010

Geographic And Breed Distribution Patterns Of An A/G Polymorphism Present In The Mx Gene Suggests Balanced Selection In Village Chickens, S. Ommeh, L. N. Jin, H. Eding, F. C. Muchadeyi, S. Sulandari, M. S.A. Zein, G. Danbaro, C. E. Wani, S. G. Zhao, Q. H. Nie, X. Q. Zhang, M. Ndila, R. Preisinger, G. H. Chen, I. A. Yousif, K. N. Heo, S. J. Oh, M. Tapio, D. Masiga, O. Hanotte, H. Jianlin, S. Weigend

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An A/G Single Nucleotide Polymorphism (SNP) at position 1,892 of the Mx gene coding sequence has been linked to susceptibility/resistance to avian viral infection in vitro. Using PCR-RFLP and sequencing methods, 1,946 samples from 109 populations from Asia, Africa and Europe; grouped as indigenous village, commercial, fancy chicken as well as wild junglefowl were genotyped for the polymorphism. Allele and genotype frequencies were calculated. Only the G allele was present in Ceylon junglefowl Gallus lafayetti. Using the wild red junglefowl G. gallus population as reference, we assessed if the A/G alleles and genotypes frequencies have been affected by the breeding …

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Mate-Odour Identification By Both Sexes Of Evarcha Culicivora, An East African Jumping Spider, Fiona R. Cross, Robert R. Jackson May 2009

Mate-Odour Identification By Both Sexes Of Evarcha Culicivora, An East African Jumping Spider, Fiona R. Cross, Robert R. Jackson

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Evarcha culicivora is an unusual salticid spider because each sex actively courts the other and both sexes make distinctive mate-choice decisions. Here we use olfactometer experiments for investigating the ability of each sex to identify potential mates on the basis of odour alone. Test spiders spent more time in the vicinity of opposite-sex conspecific source spiders, regardless of whether or not these source spiders had previously mated, when the alternatives were conspecific individuals of the same sex, juveniles or a control (no odour source). This trend held regardless of the test spider's and source spider's age after reaching maturity and, …

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Unforeseen Misuses Of Bed Nets In Fishing Villages Along Lake Victoria, Noboru Minakawa, Gabriel O. Dida, Gorge O. Sonye, Kyoko Futami, Satoshi Kaneko Sep 2008

Unforeseen Misuses Of Bed Nets In Fishing Villages Along Lake Victoria, Noboru Minakawa, Gabriel O. Dida, Gorge O. Sonye, Kyoko Futami, Satoshi Kaneko

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Background. To combat malaria, the Kenya Ministry of Health and nongovernmental organizations (NGOs) have distributed insecticide-treated nets (ITNs) for use over beds, with coverage for children under five years of age increasing rapidly. Nevertheless, residents of fishing villages have started to use these bed nets for drying fish and fishing in Lake Victoria. This study investigated the extent of bed net misuse in fishing villages. Methods. Seven fishing villages along the lake were surveyed to estimate how widely bed nets were being used for fishing and drying fish. Villagers were asked why they used the bed nets for such purposes. …

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Eco-Social Analysis Of An East African Agro-Pastoral System: Management Of Tsetse And Bovine Trypanosomiasis, Johann Baumgärtner, Gianni Gilioli, Getachew Tikubet, Andrew Paul Gutierrez Mar 2008

Eco-Social Analysis Of An East African Agro-Pastoral System: Management Of Tsetse And Bovine Trypanosomiasis, Johann Baumgärtner, Gianni Gilioli, Getachew Tikubet, Andrew Paul Gutierrez

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A key constraint for development of many East African agro-pastoral communities is African animal trypanosomiasis or nagana caused by Trypanosoma spp. and vectored by species of tsetse flies (Glossina spp.). Suppression of trypanosomiasis through trapping of tsetse fly populations was conducted from 1995 to 2005 at and near Luke, Southwest Ethiopia. Odor baited mass trapping technology was used to suppress adult fly populations to very low levels while tryponocidal drugs were used to treat trypanosome infections in cattle. Data on ecological, economic and social variables were collected and analyzed in the context of eco-social dynamics in the community. The bio-economic …

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Livestock Farmers' Perception And Epidemiology Of Bovine Trypanosomosis In Kwale District, Kenya, S. O. Ohaga, E. D. Kokwaro, I. O. Ndiege, A. Hassanali, R. K. Saini Jun 2007

Livestock Farmers' Perception And Epidemiology Of Bovine Trypanosomosis In Kwale District, Kenya, S. O. Ohaga, E. D. Kokwaro, I. O. Ndiege, A. Hassanali, R. K. Saini

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We did cross-sectional surveys in Kwale District, Kenya to determine the epidemiology of bovine trypanosomosis and livestock owners' perceptions of the disease. The surveys involved relative importance of trypanosomosis, examination of the current disease constraints, current control practices and drug-use patterns. Informal meetings were held with farmers and cattle census undertaken. Tsetse-fly densities and trypanosomosis prevalences in cattle were determined. A total of 132 farmers were interviewed. Trypanosomosis, anaplasmosis, East Coast fever, foot-and-mouth diseases were reported to be the major constraints to livestock production. Trypanosomosis was the most important compared to other diseases. Chemotherapy was the most widely used method …

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Plant Growth-Promoting Rhizobacteria Do Not Pose Any Deleterious Effect On Cowpea And Detectable Amounts Of Ethylene Are Produced, Olubukola O. Babalola, Abiodun I. Sanni, George D. Odhiambo, Baldwyn Torto Jun 2007

Plant Growth-Promoting Rhizobacteria Do Not Pose Any Deleterious Effect On Cowpea And Detectable Amounts Of Ethylene Are Produced, Olubukola O. Babalola, Abiodun I. Sanni, George D. Odhiambo, Baldwyn Torto

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The use of trap crops such as cowpea could reduce the effects of the root parasitic weed, Striga hermonthica and its subsequent constraints on the growth of cereals. Certain bacteria could augment the trap crop stimulatory effect. We studied the effect of three bacteria introduced to the rhizosphere of three cowpea varieties at planting. Number of days to cowpea flowering was noted and at harvest, data were collected on pod characteristics and biomass. Means of data subjected to ANOVA were compared using Tukey's Studentized Range Test. We analysed bacterial headspace volatiles for ethylene by gas chromatography and gas chromatography-mass spectrometry. …

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Development Of Pcr-Based Chloroplast Dna Markers That Characterize Domesticated Cowpea (Vigna Unguiculata Ssp. Unguiculata Var. Unguiculata) And Highlight Its Crop-Weed Complex, Y. Feleke, R. S. Pasquet, P. Gepts Nov 2006

Development Of Pcr-Based Chloroplast Dna Markers That Characterize Domesticated Cowpea (Vigna Unguiculata Ssp. Unguiculata Var. Unguiculata) And Highlight Its Crop-Weed Complex, Y. Feleke, R. S. Pasquet, P. Gepts

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In 1992, Vaillancourt and Weeden discovered a very important mutation for studying cowpea evolution and domestication. A loss of a BamHI restriction site in chloroplast DNA characterized all domesticated accessions and a few wild (Vigna unguiculata ssp. unguiculata var. spontanea) accessions. In order to screen a larger number of accessions, primers were designed to check this mutation using PCR RFLP or direct PCR methods. Using these new primers, 54 domesticated cowpea accessions and 130 accessions from the wild progenitor were screened. The absence of haplotype 0 was confirmed within domesticated accessions, including primitive landraces from cultivar-groups Biflora and Textilis, suggesting …

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Combined Control Of Striga Hermonthica And Stemborers By Maize-Desmodium Spp. Intercrops, Zeyaur R. Khan, John A. Pickett, Lester J. Wadhams, Ahmed Hassanali, Charles A.O. Midega Sep 2006

Combined Control Of Striga Hermonthica And Stemborers By Maize-Desmodium Spp. Intercrops, Zeyaur R. Khan, John A. Pickett, Lester J. Wadhams, Ahmed Hassanali, Charles A.O. Midega

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The African witchweed (Striga spp.) and lepidopteran stemborers are two major biotic constraints to the efficient production of maize in sub-Saharan Africa. Previous studies had shown the value of intercropping maize with Desmodium uncinatum in the control of both pests. The current study was conducted to assess the potential role of other Desmodium spp., adapted to different agro-ecologies, in combined control of both pests in Kenya. Treatments consisted of intercropped plots of a Striga hermonthica- and stemborer-susceptible maize variety and one Desmodium sp. or cowpea, with a maize monocrop plot included as a control. S. hermonthica counts and stemborer damage …

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Relationships Of Intercropped Maize, Stem Borer Damage To Maize Yield And Land-Use Efficiency In The Humid Forest Of Cameroon, A. Chabi-Olaye, C. Nolte, F. Schulthess, C. Borgemeister Oct 2005

Relationships Of Intercropped Maize, Stem Borer Damage To Maize Yield And Land-Use Efficiency In The Humid Forest Of Cameroon, A. Chabi-Olaye, C. Nolte, F. Schulthess, C. Borgemeister

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Stem borers are the most important maize pests in the humid forest zone of Cameroon. Field trials were conducted in the long and short rainy seasons of 2002 and 2003 to assess the level of damage and yield reductions caused by stem borers in monocropped maize and in maize intercropped with non-host plants such as cassava, cowpea and soybean. The intercrops were planted in two spatial arrangements, i.e. alternating hills or alternating rows. All intercrops and the maize monocrop were grown with and without insecticide treatment for assessment of maize yield loss due to borer attacks. The land-use efficiency of …

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Genetic Diversity In Cowpea [Vigna Unguiculata (L.) Walp.] As Revealed By Rapd Markers, Fana Sylla Ba, Remy S. Pasquet, Paul Gepts Aug 2004

Genetic Diversity In Cowpea [Vigna Unguiculata (L.) Walp.] As Revealed By Rapd Markers, Fana Sylla Ba, Remy S. Pasquet, Paul Gepts

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The present study, using RAPD analysis, was undertaken to characterize genetic variation in domesticated cowpea and its wild progenitor, as well as their relationships. The materials used consisted of 26 domesticated accessions, including accessions from each of the five cultivar-group, and 30 wild/weedy accessions, including accessions from West, East and southern Africa. A total of 28 primers generated 202 RAPD bands. One hundred and eight bands were polymorphic among the domesticated compared to 181 among wild/weedy cowpea accessions. Wild accessions were more diverse in East Africa, which is the likely area of origin of V. unguiculata var. spontanea. Var. spontanea …

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Comparative Studies On The Infectivity Of Theileria Parva In Ticks Fed In Vitro And Those Fed On Cattle, Joseph M. Musyoki, Ellie O. Osir, Henry K. Kiara, Elizabeth D. Kokwaro Apr 2004

Comparative Studies On The Infectivity Of Theileria Parva In Ticks Fed In Vitro And Those Fed On Cattle, Joseph M. Musyoki, Ellie O. Osir, Henry K. Kiara, Elizabeth D. Kokwaro

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Nymphs of the brown ear tick, Rhipicephalus appendiculatus, were fed on heparinised bovine blood infected with Theileria parva parasites in an in vitro feeding system consisting of rabbit skin membranes. The main feeding and development parameters such as the mean attachment rate, feeding duration and engorgement weights of membrane-fed ticks were not significantly different from nymphs fed on cattle. The moulting rate was also comparable although a slight significant difference was observed. Assessment of infection prevalence and abundance with T. parva in adults indicated that the membrane-fed ticks acquired infection to the same level as those fed on cattle. Stabilates …

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Integrated Arthropod Pest Management Systems For Human Health Improvement In Africa, Johann Baumgärtner, Fritz Schulthess, Yunlong Xia Jan 2003

Integrated Arthropod Pest Management Systems For Human Health Improvement In Africa, Johann Baumgärtner, Fritz Schulthess, Yunlong Xia

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In a sub-Saharan African context, limited natural resources, infectious diseases, including those transmitted by arthropod vectors, and chronic exposure to food contaminated with mycotoxin-producing fungi which, among others, are vectored by insects, are among the major constraints to human health. Thus, pest control should be an important component in human health improvement projects. It appears that the advantages of preventive over curative methods are rarely recognised in Africa, with more emphasis being given to the search for the 'silver bullet' than to integrated control approaches. Integrated pest management (IPM) systems can be assigned to different decision-making levels as well as …

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Pathogenicity And Antifeedant Activity Of Entomopathogenic Hyphomycetes To The Cowpea Leaf Beetle, Ootheca Mutabilis Shalberg, S. Ekesi Jan 2001

Pathogenicity And Antifeedant Activity Of Entomopathogenic Hyphomycetes To The Cowpea Leaf Beetle, Ootheca Mutabilis Shalberg, S. Ekesi

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Conidial suspensions of four isolates each of Bcauvcria bassiana and Melnrhizhtm anisopliae were evaluated in the laboratory for their virulence to adult Ootlicca mntabilis. All the isolates tested were pathogenic to the beetle, but to varying degrees. Three of them, B. bassiana CPD 3 and CPD10 and M. anisopliae CPD 6 were superior to all other isolates in terms of mortality induced on adult beetle, LT50 and LC50, with B. bnssiana CPD 3 having the lowest LC50 value. In feeding assayi consumption by beetles treated with B. bnssiana CPD 3 was significantly reduced within 2 days treatment (DAT) and the …

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Cattle And Amblyomma Variegatum Odors Used In Host Habitat And Host Finding By The Tick Parasitoid, Ixodiphagus Hookeri, Fanuel A. Demas, Ahmed Hassanali, Esther N. Mwangi, Edna C. Kunjeku, Audrey R. Mabveni Jan 2000

Cattle And Amblyomma Variegatum Odors Used In Host Habitat And Host Finding By The Tick Parasitoid, Ixodiphagus Hookeri, Fanuel A. Demas, Ahmed Hassanali, Esther N. Mwangi, Edna C. Kunjeku, Audrey R. Mabveni

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The response of mated naive Ixodiphagus hookeri females to cattle and Amblyomma variegatum nymphal odors was tested in a Y-tube olfactometer. I. hookeri females were attracted to cattle urine, dung, and odors from tick- free feeding sites of A. variegatum nymphs on cattle, e.g., dewlaps, front heels, and hind heels. Tick-free scrotal odors did not attract the parasitoids. Furthermore, odors from off-host unfed and fed A. variegatum nymphs did not attract the parasitoids, despite an increase in the number of the nymphs to amplify any odor signal. A blend of odors from feeding on-host nymphs and cattle scrota attracted the …

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Susceptibility Of The Legume Flower Thrips To Metarhizium Anisopliae On Different Varieties Of Cowpea, S. Ekesi, N. K. Maniania, W. Lwande Jan 2000

Susceptibility Of The Legume Flower Thrips To Metarhizium Anisopliae On Different Varieties Of Cowpea, S. Ekesi, N. K. Maniania, W. Lwande

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The susceptibility of Megalurothrips sjostedti to Metarhizium anisopliae when reared on susceptible, tolerant, and moderately resistant varieties of cowpea at different constant temperatures was evaluated in the laboratory. Insects were exposed either to direct spray of the conidia or to fungus-treated floral tissues. Mortality was significantly higher on the moderately resistant variety at all temperatures compared to the susceptible and tolerant varieties. Correspondingly, lethal time and lethal concentration values were significantly shorter and lower, respectively, on the moderately resistant variety compared to the other varieties, thus indicating that the two control methods are compatible as part of an integrated pest …

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Selection Of Virulent Isolates Of Entomopathogenic Hyphomycetes Against Clavigralla Tomentosicollis Stål. And Evaluation In Cage Experiment Using Three Cowpea Varieties, S. Ekesi Dec 1999

Selection Of Virulent Isolates Of Entomopathogenic Hyphomycetes Against Clavigralla Tomentosicollis Stål. And Evaluation In Cage Experiment Using Three Cowpea Varieties, S. Ekesi

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The virulence of 8 isolates of entomopathogenic hyphomycetes against adult and 5th instar nymph of Clavigralla tomentosicollis was evaluated in the laboratory at 4 different concentrations of inoculum. At all concentrations, Beauveria bassiana CPD 9 and Metarhizium anisopliae CPD 5 caused the highest mortality in adult bug ranging from 58 to 97% and 53 to 100%, respectively at 7 days post inoculation. The same isolates had the shortest LT50 (3.5 and 4.1 days, respectively) and the lowest LC50 (1.8 × 105 and 9.8 × 104 conidia ml-1) values in adult insects. In nymphs, M. anisopliae CPD 5 was the most …

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Cleome Hirta Essential Oil As Livestock Tick (Rhipicephalus Appendiculatus) And Maize Weevil (Sitophilus Zeamais) Repellent, M. W. Ndungu, S. C. Chhabra, W. Lwande Oct 1999

Cleome Hirta Essential Oil As Livestock Tick (Rhipicephalus Appendiculatus) And Maize Weevil (Sitophilus Zeamais) Repellent, M. W. Ndungu, S. C. Chhabra, W. Lwande

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The repellency of the essential oil of the shrub Cleome hirta and of three identified constituents (phytol, (+)-cedrol, n-octacosane) was evaluated against the livestock tick, Rhipicephalus appendiculatus and the maize weevil, Sitophillus zeamais. In a tick climbing repellency bioassay, the oil exhibited repellency which, at the highest dose, was comparable to that of the commercial arthropod repellent N,N-diethyltoluamide (DEET). In a Y-tube olfactometer bioassay, the oil showed higher or comparable repellency against S. zeamais relative to DEET at all the doses tested. The potential of C. hirta in livestock tick and maize weevil control is discussed. Copyright (C) 1999 Elsevier …

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Trypanosome Infection Rate In Cattle At Nguruman, Kenya, R. A. Tarimo-Nesbitt, T. K. Golder, R. D. Dransfield, M. F. Chaudhury, R. Brightwell Feb 1999

Trypanosome Infection Rate In Cattle At Nguruman, Kenya, R. A. Tarimo-Nesbitt, T. K. Golder, R. D. Dransfield, M. F. Chaudhury, R. Brightwell

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Trypanosome infection rate in cattle at Nguruman was investigated in a study conducted in 1984-1986. Shifting pastoralism significantly reduced trypanosome infections in cattle. The cattle were more heavily infected with Trypanosoma congolense (16.5%) than Trypanosoma vivax (4.95%) and Trypanosoma brucei (0.19%). Trypanosoma theileri was observed only once among the cattle examined. Mixed trypanosome infections in cattle were observed to be 2.75% and 0.014% for T. congolense/T. vivax and T. congolense/T. brucei, respectively. The duration of infection in the cattle was 55 days for T. congolense and 79 days for T. vivax. High infections in cattle were observed 2 months after …

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Genetic Relationships Among Subspecies Of Vigna Unguiculata (L.) Walp. Based On Allozyme Variation, R. S. Pasquet Jan 1999

Genetic Relationships Among Subspecies Of Vigna Unguiculata (L.) Walp. Based On Allozyme Variation, R. S. Pasquet

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The cowpea [Vigna unguiculata (L.) Walp.] is a morphologically and genetically variable species composed of wild perennial, wild annual, and cultivated forms that are mainly used for edible seeds and pods. In this study, genetic variation in 199 germplasm accessions of wild and cultivated cowpea was evaluated using an allozyme analysis. The results from this survey showed that wild cowpea exhibits genetic variation perfectly fitted with the existing morphological classification. The cowpea gene-pool is characterized by its unusually large size. It encompasses taxa (ranked as subspecies) that could be considered as different species considering the high genetic distances observed between …

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Potential Of The Entomopathogenic Fungus, Metarhizium Anisopliae (Metsch.) Sorokin For Control Of The Legume Flower Thrips, Megalurothrips Sjostedti (Trybom) On Cowpea In Kenya, S. Ekesi, N. K. Maniania, K. Ampong-Nyarko, I. Onu Nov 1998

Potential Of The Entomopathogenic Fungus, Metarhizium Anisopliae (Metsch.) Sorokin For Control Of The Legume Flower Thrips, Megalurothrips Sjostedti (Trybom) On Cowpea In Kenya, S. Ekesi, N. K. Maniania, K. Ampong-Nyarko, I. Onu

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Field experiments were conducted at Mbita, western Kenya for two seasons to evaluate the potential of the entomopathogenic fungus, Metarhizium anisopliae (Metsh.) Sorokin, for biological control of the legume flower thrips, Megalurothrips sjostedti (Trybom), on cowpea. An ultra-low-volume (ULV) oil/aqueous formulation and a high-volume (HV) aqueous formulation of conidia were applied three times each at two concentrations of 1 x 1011 and 1 x 1013 conidia ha-1. Compared with the untreated controls, both formulations significantly reduced thrips populations and plant damage in both seasons. Adult insects collected from fungal-treated plots and reared in the laboratory showed a high mortality due …

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Morphological Study Of Cultivated Cowpea Vigna Unguiculata (L.) Walp. Importance Of Ovule Number And Definition Of Cv Gr Melanophthalmus, Rémy Stéphane Pasquet Jan 1998

Morphological Study Of Cultivated Cowpea Vigna Unguiculata (L.) Walp. Importance Of Ovule Number And Definition Of Cv Gr Melanophthalmus, Rémy Stéphane Pasquet

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More than 400 cultivated cowpea accessions were studied using 29 morphophysiological characters. The analysis of data contrasts evolved cultivars and more primitive cultivars (and wild forms) according to seed size on the one hand and early and late flowering (under inductive conditions) on the other hand. The latter character is markedly correlated with ovule number. Photosensitive and early-flowering photoindependent cultivars have 11-17 ovules per pod and late flowering photoindependent cultivars have 16-25 ovules per pod. The analysis leads to assigning the accessions studied to the following different cultigroups: cv gr Unguiculata, cv gr Sesquipedalis, cv gr Biflora and cv gr …

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