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International Centre of Insect Physiology and Ecology

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Articles 331 - 360 of 429

Full-Text Articles in Agricultural Science

Bed Net Use And Associated Factors In A Rice Farming Community In Central Kenya, Peter N. Ng'ang'a, Gayathri Jayasinghe, Violet Kimani, Josephat Shililu, Charity Kabutha, Lucy Kabuage, John Githure, Clifford Mutero May 2009

Bed Net Use And Associated Factors In A Rice Farming Community In Central Kenya, Peter N. Ng'ang'a, Gayathri Jayasinghe, Violet Kimani, Josephat Shililu, Charity Kabutha, Lucy Kabuage, John Githure, Clifford Mutero

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Background. Use of insecticide-treated nets (ITNs) continues to offer potential strategy for malaria prevention in endemic areas. However their effectiveness, sustainability and massive scale up remain a factor of socio-economic and cultural variables of the local community which are indispensable during design and implementation stages. Methods. An ethnographic household survey was conducted in four study villages which were purposefully selected to represent socio-economic and geographical diversity. In total, 400 households were randomly selected from the four study villages. Quantitative and qualitative information of the respondents were collected by use of semi-structured questionnaires and focus group discussions. Results. Malaria was reported …

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Evaluation Of Farmers' Field Days As A Dissemination Tool For Push-Pull Technology In Western Kenya, David M. Amudavi, Zeyaur R. Khan, Japhether M. Wanyama, Charles A.O. Midega, Jimmy Pittchar, Ahmed Hassanali, John A. Pickett Mar 2009

Evaluation Of Farmers' Field Days As A Dissemination Tool For Push-Pull Technology In Western Kenya, David M. Amudavi, Zeyaur R. Khan, Japhether M. Wanyama, Charles A.O. Midega, Jimmy Pittchar, Ahmed Hassanali, John A. Pickett

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Our earlier study on farmers' adoption of 'Push-pull' technology (PPT) for management of cereal stemborers and Striga weed showed that field days (FDs) could be effective in technology dissemination. Hence, in an effort to utilize effective and economical dissemination strategies, we undertook a detailed study in 2007 to assess their effectiveness in PPT dissemination by interviewing 1492 participants randomly selected during participation in FDs. A majority (80%) of the respondents learnt about the biology and damage caused by stemborers and Striga, how PPT works, how to implement PPT and utilize its products, among others. Consequently, over 70% of them favoured …

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Spatiotemporal Dynamics Of Immature Culicines (Subfamily Culicinae) And Their Larval Habitats In Mwea Rice Scheme, Kenya, Ephantus J. Muturi, Joseph M. Mwangangi, Benjamin G. Jacob, Josephat I. Shililu, Charles M. Mbogo, John I. Githure, Robert J. Novak Mar 2009

Spatiotemporal Dynamics Of Immature Culicines (Subfamily Culicinae) And Their Larval Habitats In Mwea Rice Scheme, Kenya, Ephantus J. Muturi, Joseph M. Mwangangi, Benjamin G. Jacob, Josephat I. Shililu, Charles M. Mbogo, John I. Githure, Robert J. Novak

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An ecological study was conducted at three study sites in Mwea Rice Scheme, Kenya to identify the diverse aquatic habitats in which culicine mosquitoes thrived and to explore the best strategies for mosquito control in the area. During the 11-month study period, ten habitat categories and 11 culicine species mainly dominated by Culex quinquefasciatus (72.0%) and Culex annulioris (17.9%) were identified from pupae and late instars larval samples. Two of the 11 culicine species, Ficalbia (Mimomyia) plumosa and Uranotaenia spp., have not been reported previously in the study area. Rurumi had more habitat types than either of the other study …

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Field Release Of A Non-Toxigenic Aspergillus Flavus L Strain In Central Benin, A. M. Klueken, C. Borgemeister, B. Hau Jan 2009

Field Release Of A Non-Toxigenic Aspergillus Flavus L Strain In Central Benin, A. M. Klueken, C. Borgemeister, B. Hau

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Non-toxigenic strains of Aspergillus flavus (Link) can be used as biological control agents to reduce the contamination of grains such as maize with carcinogenic and immunotoxic aflatoxins. Based on its sclerotial morphology, A. flavus is commonly divided into two types: L strains and S strains. In this study, we applied the non-toxigenic A. flavus L strain BN030D to the soil of five maize fields in Djidja, central Benin, to investigate its effects on the composition of the prevailing fungal communities, on the ratio of A. flavus L strains and S strains, and on the vegetative compatibility of L strains with …

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Economic Performance Of The 'Push-Pull' Technology For Stemborer And Striga Control In Smallholder Farming Systems In Western Kenya, Zeyaur R. Khan, Charles A.O. Midega, Esther M. Njuguna, David M. Amudavi, Japhether M. Wanyama, John A. Pickett Jul 2008

Economic Performance Of The 'Push-Pull' Technology For Stemborer And Striga Control In Smallholder Farming Systems In Western Kenya, Zeyaur R. Khan, Charles A.O. Midega, Esther M. Njuguna, David M. Amudavi, Japhether M. Wanyama, John A. Pickett

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The 'push-pull' technology (PPT), developed in Africa, offers effective control of cereal stemborers and Striga weed in maize-based cropping systems. It involves intercropping maize with desmodium, Desmodium uncinatum, with Napier grass, Pennisetum purpureum, planted as border around this intercrop. Desmodium repels the stemborer moths (push) that are subsequently attracted to the Napier grass (pull). Desmodium also suppresses and eliminates Striga. We assessed economic performance of this technology compared to the conventional maize mono- and maize-bean intercropping systems in six districts in western Kenya over 4-7 years. Ten farmers were randomly recruited in each district and each planted three plots representing …

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Farmers' Perceptions Of A 'Push-Pull' Technology For Control Of Cereal Stemborers And Striga Weed In Western Kenya, Zeyaur R. Khan, David M. Amudavi, Charles A.O. Midega, Japhether M. Wanyama, John A. Pickett Jun 2008

Farmers' Perceptions Of A 'Push-Pull' Technology For Control Of Cereal Stemborers And Striga Weed In Western Kenya, Zeyaur R. Khan, David M. Amudavi, Charles A.O. Midega, Japhether M. Wanyama, John A. Pickett

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Striga and cereal stemborers are major constraints to cereal production in sub-Saharan Africa causing serious food security concerns. The International Centre of Insect Physiology and Ecology (ICIPE) and partners have developed a novel integrated management system called the 'push-pull' technology (PPT) in mitigation. This involves inter-cropping maize with a stemborer moth-repellent forage legume, silverleaf desmodium (push), and planting an attractive trap crop, Napier grass (pull), around the intercrop. Additionally, chemicals produced from desmodium roots inhibit Striga. We evaluated farmers' perceptions of the pests, PPT attributes and factors influencing the likelihood of its adoption in 15 districts in western Kenya. A …

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Potential Of Improved Fallows To Increase Household And Regional Fuelwood Supply: Evidence From Western Kenya, B. A. Jama, J. K. Mutegi, A. N. Njui Jun 2008

Potential Of Improved Fallows To Increase Household And Regional Fuelwood Supply: Evidence From Western Kenya, B. A. Jama, J. K. Mutegi, A. N. Njui

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Fuelwood is the main energy source for households in rural Africa, but its supply is rapidly declining especially in the densely populated areas. Short duration planted tree fallows, an agroforestry technology widely promoted in sub-Sahara Africa for soil fertility improvement may offer some remedy. Our objective was to determine the fuelwood production potential of 6, 12 and 18 months (the common fallow rotation periods) old Crotalaria grahamiana, Crotalaria paulina, Tephrosia vogelli and Tephrosia candida fallows under farmer-managed conditions in western Kenya. Based on plot-level yields, we estimated the extent to which these tree fallows would meet household and sub-national fuelwood …

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Integrated Management Of Striga Hermonthica, Stemborers, And Declining Soil Fertility In Western Kenya, B. Vanlauwe, F. Kanampiu, G. D. Odhiambo, H. De Groote, L. J. Wadhams, Z. R. Khan May 2008

Integrated Management Of Striga Hermonthica, Stemborers, And Declining Soil Fertility In Western Kenya, B. Vanlauwe, F. Kanampiu, G. D. Odhiambo, H. De Groote, L. J. Wadhams, Z. R. Khan

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Striga hermonthica (Delile) Benth., stemborers, and declining soil fertility are serious threats to sustainable food production in the Lake Victoria zone of Kenya. To address these constraints, promising integrated crop management technologies were evaluated, using a multi-locational design in four sub-locations in Siaya and Vihiga district (western Kenya) for six cropping seasons. Technologies evaluated consisted of the traditional maize (Zea mays L.) - bean (Phaseolus vulgaris L.) intercrop, maize - Desmodium (Desmodium uncinatum (Jacq.) DC.) push-pull intercrop, Crotalaria (Crotalaria ochroleuca G. Don) - maize rotation, and soybean (Glycine max (L.) Merr) - maize rotation. Within each of these systems, imazapyr-coated …

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Blood-Feeding Patterns Of Culex Quinquefasciatus And Other Culicines And Implications For Disease Transmission In Mwea Rice Scheme, Kenya, Ephantus J. Muturi, Simon Muriu, Josephat Shililu, Joseph M. Mwangangi, Benjamin G. Jacob, Charles Mbogo, John Githure, Robert J. Novak May 2008

Blood-Feeding Patterns Of Culex Quinquefasciatus And Other Culicines And Implications For Disease Transmission In Mwea Rice Scheme, Kenya, Ephantus J. Muturi, Simon Muriu, Josephat Shililu, Joseph M. Mwangangi, Benjamin G. Jacob, Charles Mbogo, John Githure, Robert J. Novak

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Studies were conducted in Mwea Rice Scheme, Kenya during the period April 2005 and January 2007 to determine the host-feeding pattern of culicine mosquitoes. Mosquitoes were collected indoors and outdoors and tested for human, bovine, goat, and donkey blood meals by an Enzyme-Linked Immunosorbent Assay. A total of 1,714 blood-engorged samples comprising Culex quinquefasciatus Say (96.1%), Culex annulioris Theobald (1.8%), Culex poicilipes Theobald (0.9%), Aedes cuminsi Theobald (1.0%), Aedes taylori Edwards (0.1%), and Mansonia africana Theobald (0.1%) were tested. Except for A. taylori, in which the single blood meal tested was of bovine origin, the other species fed mostly on …

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Location, Acceptance And Suitability Of Lepidopteran Stemborers Feeding On A Cultivated And Wild Host-Plant To The Endoparasitoid Cotesia Flavipes Cameron (Hymenoptera: Braconidae), Meshack Obonyo, Fritz Schulthess, Juma Gerald, Onesmus Wanyama, Bruno Le Rü, Paul André Calatayud Apr 2008

Location, Acceptance And Suitability Of Lepidopteran Stemborers Feeding On A Cultivated And Wild Host-Plant To The Endoparasitoid Cotesia Flavipes Cameron (Hymenoptera: Braconidae), Meshack Obonyo, Fritz Schulthess, Juma Gerald, Onesmus Wanyama, Bruno Le Rü, Paul André Calatayud

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Maize fields in Africa are usually surrounded by land occupied by wild plants many of which harbor lepidopteran stemborer species not found on crops. It is not known if the exotic braconid parasitoid Cotesia flavipes, which was released in Kenya in 1993 against the invasive crambid Chilo partellus, searches for and attacks these borers in their natural habitats and whether they are suitable for parasitoid development. The objective of this study was to assess the relationship between acceptance and suitability of six stemborer species attacking cultivated sorghum (C. partellus, Busseola fusca, Sesamia calamistis, and S. nonagrioides) or Napier grass (Busseola …

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On-Farm Evaluation Of The 'Push-Pull' Technology For The Control Of Stemborers And Striga Weed On Maize In Western Kenya, Zeyaur R. Khan, Charles A.O. Midega, David M. Amudavi, Ahmed Hassanali, John A. Pickett Mar 2008

On-Farm Evaluation Of The 'Push-Pull' Technology For The Control Of Stemborers And Striga Weed On Maize In Western Kenya, Zeyaur R. Khan, Charles A.O. Midega, David M. Amudavi, Ahmed Hassanali, John A. Pickett

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The 'push-pull' technology is a novel pest management strategy developed for control of stemborers and striga weed, Striga hermonthica, in maize-based farming systems in eastern Africa, where maize is intercropped with desmodium, a forage legume, and Napier grass is planted as a border crop. Desmodium repels stemborer moths while Napier grass attracts them. Desmodium also suppresses the parasitic striga weed through a series of mechanisms ranging from shading to allelopathy through the root system. The technology is currently being disseminated among smallholder farmers in eastern Africa and adoption rates are rising. Our on-station studies have reported efficacy of this technology …

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Release And Establishment Of Cotesia Flavipes For Biological Control Of Maize Stemborers In Zimbabwe, P. Chinwada, F. Schulthess, W. A. Overholt, P. Jowah, C. O. Omwega Mar 2008

Release And Establishment Of Cotesia Flavipes For Biological Control Of Maize Stemborers In Zimbabwe, P. Chinwada, F. Schulthess, W. A. Overholt, P. Jowah, C. O. Omwega

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Five populations of the crambid stemborer Chilo partellus (Swinhoe) and one of the noctuid borer Busseola fusca (Fuller) from Zimbabwe were evaluated for their suitability for immature development of the exotic braconid larval parasitoid Cotesia flavipes Cameron. Successful parasitoid development occurred only on C. partellus but parasitism as well as egg-to-adult development time did not vary among the five populations. Smallest parasitoid broods, and sex ratios as the proportion of female offspring, however, were produced with C. partellus from the Muzarabani area of Zimbabwe. Co. flavipes became successfully established in five out of eight locations, where it had been released …

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Potential Of Sequential Cropping In The Management Of Root-Knot Nematodes In Okra, A. N. Mweke, J. W. Kimenju, A. A. Seif, E. W. Mutitu, G. K. Mutua Jan 2008

Potential Of Sequential Cropping In The Management Of Root-Knot Nematodes In Okra, A. N. Mweke, J. W. Kimenju, A. A. Seif, E. W. Mutitu, G. K. Mutua

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The response of different crops to a mixed population of root-knot nematodes, Meloidogyne javanica and M. incognita and their potential as suppressants in sequential cropping systems was evaluated in greenhouse and field experiments. Crops rated as resistant were five maize cultivars, four sorghum cultivars, two millet varieties, guwar and two pigeonpea cultivars which had galling indices ranging between 1.4-3.6. cowpea cv. K80 was rated as moderately resistant with a galling index of 4 while greengram and cowpea cv. KKI were rated as susceptible with galling indices ranging from 5.6 to 7.4. Four crops namely sweetcorn, babycorn, maize cv. Pioneer (Ph3253) …

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Differential Expression Of The Crv1 Haemocyte Inactivation-Associated Polydnavirus Gene In The African Maize Stem Borer Busseola Fusca (Fuller) Parasitized By Two Biotypes Of The Endoparasitoid Cotesia Sesamiae (Cameron), C. W. Gitau, D. Gundersen-Rindal, M. Pedroni, P. J. Mbugi, S. Dupas Jul 2007

Differential Expression Of The Crv1 Haemocyte Inactivation-Associated Polydnavirus Gene In The African Maize Stem Borer Busseola Fusca (Fuller) Parasitized By Two Biotypes Of The Endoparasitoid Cotesia Sesamiae (Cameron), C. W. Gitau, D. Gundersen-Rindal, M. Pedroni, P. J. Mbugi, S. Dupas

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Polydnaviruses are rarely studied for their natural variation in immune suppressive abilities. The polydnavirus harboring braconid Cotesia sesamiae, a widespread endoparasitoid of Busseola fusca and Sesamia calamistis in sub-Saharan Africa exists as two biotypes. In Kenya, the western biotype completes development in B. fusca larvae. However, eggs of the coastal C. sesamiae are encapsulated in this host and ultimately, no parasitoids emerge from parasitized B. fusca larvae. Both biotypes develop successfully in S. calamistis larvae. Encapsulation activity by B. fusca larvae towards eggs of the avirulent C. sesamiae was detectable six hours post-parasitization. The differences in encapsulation of virulent and …

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Cross-Modality Effects During Male-Male Interactions Of Jumping Spiders, Fiona R. Cross, Robert R. Jackson, Simon D. Pollard, Mark W. Walker Jul 2007

Cross-Modality Effects During Male-Male Interactions Of Jumping Spiders, Fiona R. Cross, Robert R. Jackson, Simon D. Pollard, Mark W. Walker

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An important prediction from game theory is that the value of a resource influences the level to which male-male conflict escalates. Earlier experimental studies have shown that the seven salticid species we study here (Bavia aericeps, Euryattus sp., Hypoblemum albovittatum, Jacksonoides queenslandicus, Marpissa marina, Portia africana and Simaetha paetula) determine by sight whether a female is a conspecific or a heterospecific and then escalate the intensity with which they interact (i.e., they adopt behaviour that is likely to put them at greater risk of injury after detecting the presence of a conspecific female). Here the earlier studies are extended by …

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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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C-Methylated And C-Prenylated Isoflavonoids From Root Extract Of Desmodium Uncinatum, Salome M. Guchu, Abiy Yenesew, Muniru K. Tsanuo, Nicholas K. Gikonyo, John A. Pickett, Antony M. Hooper, Ahmed Hassanali Mar 2007

C-Methylated And C-Prenylated Isoflavonoids From Root Extract Of Desmodium Uncinatum, Salome M. Guchu, Abiy Yenesew, Muniru K. Tsanuo, Nicholas K. Gikonyo, John A. Pickett, Antony M. Hooper, Ahmed Hassanali

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A pterocarpan, 1,9-dihydroxy-3-methoxy-2-methylpterocarpan (named uncinacarpan) and two isoflavanones, 5,7-dihydroxy-2′,3′,4′-trimethoxy-6-(3-methylbut-2-enyl)isoflavanone (named uncinanone D) and 5,4′-dihydroxy-7,2′-dimethoxy-6-methylisoflavanone (named uncinanone E), were isolated from the CH2Cl2 root extract of Desmodium uncinatum (Jacq.) DC and characterised by spectroscopic methods. In addition, a rare pterocarpan edudiol and two known abietane diterpenes, 7-oxo-15-hydroxydehydroabietic acid and 7-hydroxycallitrisic acid were identified. The fraction of the root extract that was analysed induced germination of Striga hermonthica seeds, but none of the isolated compounds showed this activity. © 2006 Elsevier Ltd. All rights reserved.

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Distribution And Relative Importance Of Lepidopteran Cereal Stemborers And Their Parasitoids In Uganda, T. Matama-Kauma, F. Schulthess, J. A. Ogwang, J. M. Mueke, C. O. Omwega Jan 2007

Distribution And Relative Importance Of Lepidopteran Cereal Stemborers And Their Parasitoids In Uganda, T. Matama-Kauma, F. Schulthess, J. A. Ogwang, J. M. Mueke, C. O. Omwega

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Infestation levels and parasitism of lepidopteran stemborers on maize were assessed in four agroecological zones (AEZ) in Uganda. The indigenous noctuid Busseola fusca Fuller (Noctuidae) and the invasive Chilo partellus Swinhoe (Crambidae) were the most important stemborers recorded. C. partellus represented 77% of the stemborers in the Eastern AEZ while B. fusca was dominant in the other AEZs, accounting for 60-79%. The proportion of infested plants was between 16% and 45% and borer density between 0.2 and 1.0 borers per plant. There was no clear relationship between damage and stem tunneling, which is often used to estimate yield loss. Telenomus …

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Larval Habitat Dynamics And Diversity Of Culex Mosquitoes In Rice Agro-Ecosystem In Mwea, Kenya, Ephantus J. Muturi, Josephat I. Shililu, Weidong Gu, Benjamin G. Jacob, John I. Githure, Robert J. Novak Jan 2007

Larval Habitat Dynamics And Diversity Of Culex Mosquitoes In Rice Agro-Ecosystem In Mwea, Kenya, Ephantus J. Muturi, Josephat I. Shililu, Weidong Gu, Benjamin G. Jacob, John I. Githure, Robert J. Novak

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Introduction of irrigation projects in developing nations has often been blamed for aggravating the problem of mosquito-borne diseases by creating ideal larval habitats for vector mosquitoes. However, whereas several studies have demonstrated the relationship between malaria vectors and irrigation, little work has been done on culicine mosquitoes despite their potential in transmission of filariasis and arboviruses and their significant biting nuisance in these areas. This study examined the diversity of Culex mosquito fauna and their larval habitats at two sites (Murinduko and Kiamachiri) in Mwea, Kenya over a 12-month period. The habitat types present at each site within a 200-meter …

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Antibacterial Activity Of Apis Mellifera L. Propolis Collected In Three Regions Of Kenya, Elliud M. Muli, J. M. Maingi Jan 2007

Antibacterial Activity Of Apis Mellifera L. Propolis Collected In Three Regions Of Kenya, Elliud M. Muli, J. M. Maingi

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The present study aimed at investigating the susceptibility of the microorganisms Pseudomonas aeruginosa, Salmonella typhi, Escherichia coli, Staphylococcus aureus, and Bacillus subtilis to ethanolic extracts of propolis (EEP) from three regions of Kenya (Taita, Tana and Samburu). Propolis was extracted using four different concentrations of ethanol: pure, 70%, 50%, and 30%. Ethanol (70%) and Streptomycin were used as controls. The agar diffusion method using filter paper disks was employed. Antibacterial activity was determined as an equivalent of the inhibition zones diameters (in millimeters) after incubation at 37°C for 24h. Significant differences in the antibacterial activities of propolis were observed among …

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Environmental Abundance Of Anopheles (Diptera: Culicidae) Larval Habitats On Land Cover Change Sites In Karima Village, Mwea Rice Scheme, Kenya, Benjamin G. Jacob, Ephantus Muturi, Patrick Halbig, Joseph Mwangangi, R. K. Wanjogu, Enock Mpanga, Jose Funes, Josephat Shililu, John Githure, James L. Regens, Robert J. Novak Jan 2007

Environmental Abundance Of Anopheles (Diptera: Culicidae) Larval Habitats On Land Cover Change Sites In Karima Village, Mwea Rice Scheme, Kenya, Benjamin G. Jacob, Ephantus Muturi, Patrick Halbig, Joseph Mwangangi, R. K. Wanjogu, Enock Mpanga, Jose Funes, Josephat Shililu, John Githure, James L. Regens, Robert J. Novak

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A study was carried out at Karima Village in the Mwea Rice Irrigation Scheme in Kenya to assess the impact of rice husbandry and associated land cover change for mosquito larval abundance. A multi-temporal, land use land cover (LULC) classification dataset incorporating distributions of Anopheles arabiensis aquatic larval habitats was produced in ERDAS Imagine version 8.7 using combined images from IKONOS at 4m spatial resolution from 2005 and Landsat Thematic Mapper (TM)™ classification data at 30-meters spatial resolution from 1988 for Karima. Of 207 larval habitats sampled, most were either canals (53.4%) or paddies (45.9%), and only one habitat was …

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Farmers' Perceptions Of Importance, Control Practices And Alternative Hosts Of Maize Stemborers In Uganda, T. Kalule, Z. R. Khan, G. Bigirwa, J. Alupo, S. Okanya, J. A. Pickett, L. J. Wadhams Dec 2006

Farmers' Perceptions Of Importance, Control Practices And Alternative Hosts Of Maize Stemborers In Uganda, T. Kalule, Z. R. Khan, G. Bigirwa, J. Alupo, S. Okanya, J. A. Pickett, L. J. Wadhams

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A survey was conducted in Tororo, Bugiri and Kapchorwa districts in eastern and northeastern Uganda on farmers' perceptions of constraints in maize production. Farmers in Tororo and Bugiri consistently ranked stemborers and striga as the major production constraints in maize growing, while those in Kapchorwa ranked stemborers and lack of capital as the most important. Approximately 35 and 40% of the farmers in Tororo and Bugiri, respectively, identified stemborers as the 'caterpillar' that destroys their maize. In Kapchorwa, 50% of the farmers identified stemborers. Pesticide application was the most common control measure while the use of indigenous and cultural control …

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Survival Of Immature Anopheles Arabiensis (Diptera: Culicidae) In Aquatic Habitats In Mwea Rice Irrigation Scheme, Central Kenya, Joseph M. Mwangangi, Ephantus J. Muturi, Josephat Shililu, Simon M. Muriu, Benjamin Jacob, Ephantus W. Kabiru, Charles M. Mbogo, John Githure, Robert Novak Nov 2006

Survival Of Immature Anopheles Arabiensis (Diptera: Culicidae) In Aquatic Habitats In Mwea Rice Irrigation Scheme, Central Kenya, Joseph M. Mwangangi, Ephantus J. Muturi, Josephat Shililu, Simon M. Muriu, Benjamin Jacob, Ephantus W. Kabiru, Charles M. Mbogo, John Githure, Robert Novak

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Background: The survivorship and distribution of Anopheles arabiensis larvae and pupae was examined in a rice agroecosystem in Mwea Irrigation Scheme, central Kenya, from August 2005 to April 2006, prior to implementation of larval control programme. Methods: Horizontal life tables were constructed for immatures in semi-field condition. The time spent in the various immature stages was determined and survival established. Vertical life tables were obtained from five paddies sampled by standard dipping technique. Results: Pre-adult developmental time for An. arabiensis in the trays in the experimental set up in the screen house was 11.85 days from eclosion to emergence. The …

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Electrophysiological Responses Of The Lepidopterous Stemborers Chilo Partellus And Busseola Fusca To Volatiles From Wild And Cultivated Host Plants, M. A. Birkett, K. Chamberlain, Z. R. Khan, J. A. Pickett, T. Toshova, L. J. Wadhams, C. M. Woodcock Nov 2006

Electrophysiological Responses Of The Lepidopterous Stemborers Chilo Partellus And Busseola Fusca To Volatiles From Wild And Cultivated Host Plants, M. A. Birkett, K. Chamberlain, Z. R. Khan, J. A. Pickett, T. Toshova, L. J. Wadhams, C. M. Woodcock

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The stemborers Chilo partellus and Busseola fusca are major pests of subsistence cereal farming in Africa. Volatiles released by two cultivated hosts, sorghum and maize (Sorghum bicolor and Zea mays), and two wild grass hosts, Pennisetum purpureum and Hyparrhenia tamba, were collected by air entrainment. Electrophysiologically active components in these samples were detected by coupled gas chromatography-electroantennography (GC-EAG), and the active peaks identified by gas chromatography-mass spectrometry. A total of 41 compounds were identified from the four plant species, all of which, as well as two unidentified compounds, elicited an electrophysiological response from one or both of the stemborers. The …

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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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A Grid-Based Infrastructure For Ecological Forecasting Of Rice Land Anopheles Arabiensis Aquatic Larval Habitats, Benjamin G. Jacob, Ephantus J. Muturi, Jose E. Funes, Josephat I. Shililu, John I. Githure, Ibulaimu I. Kakoma, Robert J. Novak Oct 2006

A Grid-Based Infrastructure For Ecological Forecasting Of Rice Land Anopheles Arabiensis Aquatic Larval Habitats, Benjamin G. Jacob, Ephantus J. Muturi, Jose E. Funes, Josephat I. Shililu, John I. Githure, Ibulaimu I. Kakoma, Robert J. Novak

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Background: For remote identification of mosquito habitats the first step is often to construct a discrete tessellation of the region. In applications where complex geometries do not need to be represented such as urban habitats, regular orthogonal grids are constructed in GIS and overlaid on satellite images. However, rice land vector mosquito aquatic habitats are rarely uniform in space or character. An orthogonal grid overlaid on satellite data of rice-land areas may fail to capture physical or man-made structures, i.e paddies, canals, berms at these habitats. Unlike an orthogonal grid, digitizing each habitat converts a polygon into a grid cell, …

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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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Population Models For Threshold-Based Control Of Tetranychus Urticae In Small-Scale Kenyan Tomato Fields And For Evaluating Weather And Host Plant Species Effects, Markus Knapp, Ibrahima Sarr, Gianni Gilioli, Johann Baumgärtner Aug 2006

Population Models For Threshold-Based Control Of Tetranychus Urticae In Small-Scale Kenyan Tomato Fields And For Evaluating Weather And Host Plant Species Effects, Markus Knapp, Ibrahima Sarr, Gianni Gilioli, Johann Baumgärtner

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The spatial distribution of motile life stages of the two-spotted spider mite Tetranychus urticae Koch in Kenyan small-scale tomato fields was described by Taylor's power law and an enumerative sampling plan was designed for research purposes. The exponential increase of T. urticae populations during three growing seasons permits the development and use of a simple exponential model for the design of a threshold-based chemical control system. For this purpose, a critical threshold of 440 motile mites per sample unit at the end of the growing season (12 weeks after transplanting) was translated into a proportion of 0.83 infested units in …

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Spatially Targeting Culex Quinquefasciatus Aquatic Habitats On Modified Land Cover For Implementing An Integrated Vector Management (Ivm) Program In Three Villages Within The Mwea Rice Scheme, Kenya, Benjamin G. Jacob, Josephat Shililu, Ephantus J. Muturi, Joseph M. Mwangangi, Simon M. Muriu, Jose Funes, John Githure, James L. Regens, Robert J. Novak May 2006

Spatially Targeting Culex Quinquefasciatus Aquatic Habitats On Modified Land Cover For Implementing An Integrated Vector Management (Ivm) Program In Three Villages Within The Mwea Rice Scheme, Kenya, Benjamin G. Jacob, Josephat Shililu, Ephantus J. Muturi, Joseph M. Mwangangi, Simon M. Muriu, Jose Funes, John Githure, James L. Regens, Robert J. Novak

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Background: Continuous land cover modification is an important part of spatial epidemiology because it can help identify environmental factors and Culex mosquitoes associated with arbovirus transmission and thus guide control intervention. The aim of this study was to determine whether remotely sensed data could be used to identify rice-related Culex quinquefasciatus breeding habitats in three rice-villages within the Mwea Rice Scheme, Kenya. We examined whether a land use land cover (LULC) classification based on two scenes, IKONOS at 4 m and Landsat Thematic Mapper at 30 m could be used to map different land uses and rice planted at different …

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