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Articles 2101 - 2130 of 2421

Full-Text Articles in Life Sciences

Use Of Reovirus Monoreassortants To Define Lysis Of Transfomed Cells, Christine Nora Mutsoli Aug 2005

Use Of Reovirus Monoreassortants To Define Lysis Of Transfomed Cells, Christine Nora Mutsoli

Biology Theses - Archive

Reovirus is known to selectively destroy transformed cells while establishing a persistent infection in normal cells. For this study the transformed cell lines used were L929, WI-38 VA13 2RA, T1, N1, and MYC-3. Additionally, the normal cells WI-38 and MMEC were used to examine differential sensitivity to reovirus serotypes 1, 2, and 3. Reovirus is able to replicate efficiently in L929 cells because it induces a transition from capped to uncapped translation of viral mRNA. Reovirus maintains a persistent infection in WI-38 cells, but lyses WI-38 VA13 2RA cells. Reovirus has also been demonstrated to lyse and produce more virus …

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Microencapsulating Properties Of Trehalose And Of Its Blends With Sucrose And Fructose, Marina Cerdeira, Silvana Martini, Maria L. Herrera Aug 2005

Microencapsulating Properties Of Trehalose And Of Its Blends With Sucrose And Fructose, Marina Cerdeira, Silvana Martini, Maria L. Herrera

Nutrition, Dietetics, and Food Sciences Faculty Publications

A low melting fraction of milk fat (LMF), with a dropping point (MDP) of 16.7 °C, was encapsulated by freeze-drying emulsions formulated with trehalose or its blends with 30 wt% lactose or sucrose as hydrophilic phase, and with a mixed of 50 wt% of the palmitic sucrose esters (SE) β-170 and β-1670 as emulsifiers. Trehalose or trehalose/sucrose matrices were very efficient to encapsulate LMF (retention values were 82.8%± 3.2% and 90.5%± 3.7%, dry basis, respectively), whereas trehalose/lactose showed a significant decline in initial retention (42.5%± 2.5%, dry basis). The role of emulsion stability, water content, physical state of the matrix, …

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Generalism Versus Specialism: Responses Of Diadegma Mollipla (Holmgren) And Diadegma Semiclausum (Hellen), To The Host Shift Of The Diamondback Moth (Plutella Xylostella L.) To Peas, A. Roßbach, B. Löhr, S. Vidal Jul 2005

Generalism Versus Specialism: Responses Of Diadegma Mollipla (Holmgren) And Diadegma Semiclausum (Hellen), To The Host Shift Of The Diamondback Moth (Plutella Xylostella L.) To Peas, A. Roßbach, B. Löhr, S. Vidal

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A population of the diamondback moth Plutella xylostella (L.) (Lepidoptera: Plutellidae) (DBM) was recently found to infest sugar snap- and snowpeas in the Rift Valley in Kenya, causing heavy damage. The influence of this host shift on host location preferences of two parasitoids was investigated: The indigenous Diadegma mollipla (Holmgren) regarded as a relative generalist, and Diadegma semiclausum(Hellen), regarded as highly specific to DBM. The attractiveness of different odour sources was compared for the two parasitoid species using a Y-tube olfactometer using naïve females. D. mollipla was not significantly attracted to any cabbage related odours but showed a significant preference …

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Time And Frequency Of Applications Of Entomopathogenic Nematodes And Their Persistence For Control Of Western Flower Thrips Frankliniella Occidentalis, Difabachew Belay, Lemma Ebssa, Christian Borgemeister Jul 2005

Time And Frequency Of Applications Of Entomopathogenic Nematodes And Their Persistence For Control Of Western Flower Thrips Frankliniella Occidentalis, Difabachew Belay, Lemma Ebssa, Christian Borgemeister

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Post application persistence of two entomopathogenic nematode (EPN) species, Heterorhabditis bacteriophora strain HK3 and Steinernema carpocapsae strain DD136, was studied against soil-dwelling late second instar larvae (L2) of western flower thrips (WFT) Frankliniella occidentalis (Thysanoptera: Thripidae). The nematodes were applied at 200 and 400 infective juveniles (IJ) cm-2, and L2 WFT were introduced at 0 (same day), 3, 6, 9 or 12 days after nematode application (DANA). Heterorhabditis bacteriophora caused higher thrips mortality than S. carpocapsae in most of the tests and both species persisted for at least 6 days, causing WFT mortality of up to 76 and 37.8%, respectively. …

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Effects Of Grain Legumes And Cover Crops On Maize Yield And Plant Damage By Busseola Fusca (Fuller) (Lepidoptera: Noctuidae) In The Humid Forest Of Southern Cameroon, A. Chabi-Olaye, C. Nolte, F. Schulthess, C. Borgemeister Jun 2005

Effects Of Grain Legumes And Cover Crops On Maize Yield And Plant Damage By Busseola Fusca (Fuller) (Lepidoptera: Noctuidae) In The Humid Forest Of Southern Cameroon, A. Chabi-Olaye, C. Nolte, F. Schulthess, C. Borgemeister

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Field trials were run in the humid forest zone of Cameroon to investigate the effects of crop rotation, cover crops and bush fallow on infestations by the noctuid stemborer Busseola fusca (Fuller) and on yield of maize. A continuous maize production system was compared with crop sequence systems, in which maize followed a grain legume (cowpea, soybean), cover crop (mucuna, pigeon pea) or a bush fallow. Compared to the continuous maize cropping system, maize in the crop sequence with legume and fallow systems had significantly higher leaf and stem nitrogen content at 35 and 63 days after planting (DAP), respectively. …

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Environmental, Genetic, And Maternal Effects On Life-History Traits Of The Striped Ground Cricket, Allonemobius Socius, Diana Lea Huestis Jun 2005

Environmental, Genetic, And Maternal Effects On Life-History Traits Of The Striped Ground Cricket, Allonemobius Socius, Diana Lea Huestis

Biology Theses - Archive

Organismal fitness is affected by environmental and genetic factors. More importantly, an interaction between an individual's genotype and current environmental conditions influences the success of that individual in its environment. Significant geographic and environmental correlates of allele frequencies at the Idh-1 locus, combined with a significant genotype-by-environment (GxE) interaction between Idh-1 genotype and temperature that affected fitness of Allonemobius socius, support the hypothesis that allele distributions in this species are the result of natural selection on performance of different genotypes at different temperatures. Additionally, I found that an interaction between parental diapause history and egg-incubation temperature affected the proportion of …

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Life Tables, Key Factor Analysis And Density Relations Of Natural Populations Of The Spotted Maize Stemborer, Chilo Partellus (Lepidoptera: Crambidae), Under Different Cropping Systems At The Kenyan Coast, C. A.O. Midega, C. K.P.O. Ogol, W. A. Overholt Jun 2005

Life Tables, Key Factor Analysis And Density Relations Of Natural Populations Of The Spotted Maize Stemborer, Chilo Partellus (Lepidoptera: Crambidae), Under Different Cropping Systems At The Kenyan Coast, C. A.O. Midega, C. K.P.O. Ogol, W. A. Overholt

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Studies were conducted at Mtwapa, in the coastal area of Kenya, during the long and short rains of 1999 and 2000 to evaluate interaction of mortality factors in lowering Chilo partellus (Swinhoe) populations in diverse agroecosystems. Treatments consisted of hedgerows of leucaena only, gliricidia only, alternating rows of leucaena and gliricidia, and three plots without trees. During the cropping seasons, maize was planted between the hedgerows while a row of cowpea was planted between the rows of maize. One of the plots without trees was planted to an intercrop of maize and cowpea. The remaining two plots without trees were …

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Spider Heuristics, Fiona R. Cross, Robert R. Jackson May 2005

Spider Heuristics, Fiona R. Cross, Robert R. Jackson

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Simple heuristics may help explain how even a spider, despite its minute brain, can be disturbingly intelligent. Hutchinson and Gigerenzer suggest that the generalist-specialist distinction (or more accurately the predictability-unpredictability distinction) may be related to a species' level of reliance on simple heuristics, and spider behaviour may present some especially instructive opportunities for investigating these ideas. Daniel Dennett's distinction between Darwinian, Skinnerian and Popperian animals might be useful for discerning the different contexts in which optimality considerations and individual decision making are relevant. © 2005 Elsevier B.V. All rights reserved.

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In-Situ Monitoring Of Solid Fat Content By Means Of P-Nmr And Ultrasonics, Silvana Martini, Constantin Bertoli, Maria Lidia Herrera, Ian Neeson, Alejandro Marangoni May 2005

In-Situ Monitoring Of Solid Fat Content By Means Of P-Nmr And Ultrasonics, Silvana Martini, Constantin Bertoli, Maria Lidia Herrera, Ian Neeson, Alejandro Marangoni

Nutrition, Dietetics, and Food Sciences Faculty Publications

An ultrasonic technique was developed to study the crystallization process of edible fats on-line. A chirp wave was used instead of the conventional pulser signal, thus achieving a higher signal-to-noise ratio. This enabled measurements to be made in concentrated systems [≈20% solid fat content (SFC)] through a 8.11-cm thick sample without significant signal loss. Fat samples were crystallized at 20, 25, and 30°C at a constant agitation rate of 400 rpm for 90 min. The crystallization process was followed by ultrasonic spectroscopy and a low-resolution pulsed nuclear magnetic resonance spectrometer. Specific relationships were found between ultrasonic parameters [integrated response, time …

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New Technologies To Determine Solid Fat Content On-Line, Silvana Martini, Maria Lidia Herrera, Alejandro Marangoni May 2005

New Technologies To Determine Solid Fat Content On-Line, Silvana Martini, Maria Lidia Herrera, Alejandro Marangoni

Nutrition, Dietetics, and Food Sciences Faculty Publications

The determination of solid fat content (SFC) is an important analytical procedure in the food industry. The most common way to determine SFC is by low-resolution pulsed NMR (p-NMR). Although this technique is very sensitive and easy to use, it has the disadvantage that it cannot be used for on-line measurements. The present work compares new technologies to determine SFC on-line. On-line ultrasonic spectroscopy and NMR-MOUSE (NMR mobile universal surface explorer) techniques were compared with off-line p-NMR measurements and there was a good correlation between the values obtained. Ultrasonic measurements accurately described the SFC variation, whereas NMR-MOUSE determinations need to …

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Attenuation Of Ultrasonic Waves: Influence Of Microstructure And Solid Fat Content, Silvana Martini, Constantin Bertoli, Maria Lidia Herrera, Ian Neeson, Alejandro Marangoni May 2005

Attenuation Of Ultrasonic Waves: Influence Of Microstructure And Solid Fat Content, Silvana Martini, Constantin Bertoli, Maria Lidia Herrera, Ian Neeson, Alejandro Marangoni

Nutrition, Dietetics, and Food Sciences Faculty Publications

Ultrasonic technology can be used to monitor the crystallization of fats and determine solid fat content (SFC) online. Ultrasonic waves are attenuated as crystals form and grow, and this attenuation occurs first at higher frequencies. The attenuation of the ultrasonic signal does not depend on the induction times of crystallization of the systems, or on their thermal behavior; but it does depend on SFC and on microstructure, particularly on the crystal size. At low SFC values (≈5%), bigger crystals generate more attenuation. At intermediate SFC values (≈10%), crystal size does not affect signal attenuation and SFC is the key factor …

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Rhabditis (Oscheius) Colombiana N. Sp. (Nematoda: Rhabditidae), A Necromenic Associate Of The Subterranean Burrower Bug Cyrtomenus Bergi (Hemiptera: Cydnidae) From The Cauca Valley, Colombia, S. Patricia Stock, Ana M. Caicedo, Paul A. Calatayud May 2005

Rhabditis (Oscheius) Colombiana N. Sp. (Nematoda: Rhabditidae), A Necromenic Associate Of The Subterranean Burrower Bug Cyrtomenus Bergi (Hemiptera: Cydnidae) From The Cauca Valley, Colombia, S. Patricia Stock, Ana M. Caicedo, Paul A. Calatayud

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Rhabditis (Oscheius) colombiana n. sp. is described as a necromenic associate of the burrower bug Cyrtomenus bergi (Hemiptera: Cydnidae) collected in the Cauca Valley, Colombia. The new species resembles others of the insectivora-group, viz, Rhabditis (O.) insectivora Körner, 1954 and Rhabditis (O.) lucianii Maupas, 1919, in a number of morphological and life history traits, but can be separated by a combination of morphological and morphometric characters. The most distinctive morphological features that separate R. (O.) colombiana n. sp. from these two Rhabditis species are the total size of both males and females, which are much shorter and slimmer in the …

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Fumigant Toxicity Of The Essential Oils Of Some African Plants Against Anopheles Gambiae Sensu Stricto, M. O. Omolo, D. Okinyo, I. O. Ndiege, W. Lwande, A. Hassanali Mar 2005

Fumigant Toxicity Of The Essential Oils Of Some African Plants Against Anopheles Gambiae Sensu Stricto, M. O. Omolo, D. Okinyo, I. O. Ndiege, W. Lwande, A. Hassanali

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The essential oils from 15 species of African plants selected by ethnobotanical considerations and field inspection (odour and presence of insects) were screened for fumigant toxicity to Anopheles gambiae s.s. in the laboratory. Essential oils from 6 species showed varying levels of toxicity, with Conyza newii (Compositae) and Plectranthus marruboides (Labiateae) being the most potent. Fifty compounds representing ∼74% of the essential oil of C. newii were identified by GC-MS and GC-coinjection (for available standards). The major and some of the minor constituents of the two oils were assayed at different doses. Two compounds, from C. newii, perillaldehyde and perillyl …

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Close-Range Host Searching Behavior Of The Stemborer Parasitoids Cotesia Sesamiae And Dentichasmias Busseolae: Influence Of A Non-Host Plant Melinis Minutiflora, Linnet S. Gohole, William A. Overholt, Zeyaur R. Khan, Louise E.M. Vet Mar 2005

Close-Range Host Searching Behavior Of The Stemborer Parasitoids Cotesia Sesamiae And Dentichasmias Busseolae: Influence Of A Non-Host Plant Melinis Minutiflora, Linnet S. Gohole, William A. Overholt, Zeyaur R. Khan, Louise E.M. Vet

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Studies were conducted on the host searching behavior of the larval parasitoid Cotesia sesamiae (Cameron) (Hymenoptera: Braconidae) and the pupal parasitoid Dentichasmias busseolae Heinrich (Hymenoptera: Ichneumonidae), both of which attack lepidopteran (Crambidae, Noctuidae) cereal stemborers. The behavior of D. busseolae was observed in a diversified habitat that consisted of stemborer host plants (maize, Zea mays L. and sorghum, Sorghum bicolor (L). Moench (Poaceae)) and a non-host plant (molasses grass, Melinis minutiflora Beauv. (Poaceae)), while C. sesamiae was observed separately on host plants and molasses grass. In previous olfactometer studies, C. sesamiae was attracted to molasses grass volatiles while D. busseolae …

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Location Of Stemborer Pupae In Various Host Plants And Implications For The Performance Of Natural Enemies With Emphasis On The Pupal Parasitoid Xanthopimpla Stemmator (Hymenoptera: Ichneumonidae), J. J. Muturi, A. J. Ngi-Song, F. Schulthess, J. M. Mueke, M. Sétamou Mar 2005

Location Of Stemborer Pupae In Various Host Plants And Implications For The Performance Of Natural Enemies With Emphasis On The Pupal Parasitoid Xanthopimpla Stemmator (Hymenoptera: Ichneumonidae), J. J. Muturi, A. J. Ngi-Song, F. Schulthess, J. M. Mueke, M. Sétamou

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In order to predict host accessibility by the pupal parasitoid Xanthopimpla stemmator (Thunberg), four grass species (Sorghum bicolor, Pennisetum purpureum, Sorghum arundinaceum and Zea mays) were sampled for stemborer pupae in Kwale, in the low altitudes of southern Kenya, and in Trans-Nzoia, in the high altitudes of western Kenya. The pupal position of Chilo orichalcociliellus (Strand), Chilo partellus (Swinhoe), Sesamia calamistis Hampson, Sesamia sp. nr oriaula (Tams and Bowden) and Busseola fusca (Fuller) in the plant were determined in relation to (a) the distance of pupae from the edge of the stem (depth), (b) the distance between the moth-exit hole …

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Storage Of Sunflower-Seeds: Variation On The Wax Content Of The Oil, Silvana Martini, Maria Cristina Anon Feb 2005

Storage Of Sunflower-Seeds: Variation On The Wax Content Of The Oil, Silvana Martini, Maria Cristina Anon

Nutrition, Dietetics, and Food Sciences Faculty Publications

Storage conditions of oil seeds before industrial extraction might influence the quality of the crude oil. The objective of this work was to study the influence of sunflower seed storage conditions (temperature and time) on the quality of the resulting oil in terms of its wax content and composition. Sunflower seeds were stored under different conditions, 10, 21 and 37 °C, in sealed recipients. Extractions of the seeds with hexane were made to obtain the oil at different storage times. The amount of oil extracted (25–40%) showed no significant differences with storage conditions. Wax content of the samples was determined …

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Comparative Performance Of The Mbita Trap, Cdc Light Trap And The Human Landing Catch In The Sampling Of Anopheles Arabiensis, An. Funestus And Culicine Species In A Rice Irrigation In Western Kenya, Evan M. Mathenge, Gedion O. Misiani, David O. Oulo, Lucy W. Irungu, Paul N. Ndegwa, Tom A. Smith, Gerry F. Killeen, Bart G.J. Knols Jan 2005

Comparative Performance Of The Mbita Trap, Cdc Light Trap And The Human Landing Catch In The Sampling Of Anopheles Arabiensis, An. Funestus And Culicine Species In A Rice Irrigation In Western Kenya, Evan M. Mathenge, Gedion O. Misiani, David O. Oulo, Lucy W. Irungu, Paul N. Ndegwa, Tom A. Smith, Gerry F. Killeen, Bart G.J. Knols

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Background: Mosquitoes sampling is an important component in malaria control. However, most of the methods used have several shortcomings and hence there is a need to develop and calibrate new methods. The Mbita trap for capturing host-seeking mosquitoes was recently developed and successfully tested in Kenya. However, the Mbita trap is less effective at catching outdoor-biting Anopheles funestus and Anopheles arabiensis in Madagascar and, thus, there is need to further evaluate this trap in diverse epidemiological settings. This study reports a field evaluation of the Mbita trap in a rice irrigation scheme in Kenya. Methods: The mosquito sampling efficiency of …

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Host Genotype By Parasite Genotype Interactions Underlying The Resistance Of Anopheline Mosquitoes To Plasmodium Falciparum, Louis Lambrechts, Jean Halbert, Patrick Durand, Louis C. Gouagna, Jacob C. Koella Jan 2005

Host Genotype By Parasite Genotype Interactions Underlying The Resistance Of Anopheline Mosquitoes To Plasmodium Falciparum, Louis Lambrechts, Jean Halbert, Patrick Durand, Louis C. Gouagna, Jacob C. Koella

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Background: Most studies on the resistance of mosquitoes to their malaria parasites focus on the response of a mosquito line or colony against a single parasite genotype. In natural situations, however, it may be expected that mosquito-malaria relationships are based, as are many other host-parasite systems, on host genotype by parasite genotype interactions. In such systems, certain hosts are resistant to one subset of the parasite's genotypes, while other hosts are resistant to a different subset. Methods: To test for genotype by genotype interactions between malaria parasites and their anopheline vectors, different genetic backgrounds (families consisting of the F1 offspring …

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An Str Forensic Typing System For Genetic Individualization Of Domestic Cat (Felis Catus) Samples, Marilyn A. Menotti-Raymond, Victor A. David, Leslie L. Wachter, John M. Butler, Stephen J. O'Brien Jan 2005

An Str Forensic Typing System For Genetic Individualization Of Domestic Cat (Felis Catus) Samples, Marilyn A. Menotti-Raymond, Victor A. David, Leslie L. Wachter, John M. Butler, Stephen J. O'Brien

Biology Faculty Articles

A forensic genotyping panel of 11 tetranucleotide STR loci from the domestic cat was characterized and evaluated for genetic individualization of cat tissues. We first examined 49 candidate STR loci and their frequency assessment in domestic cat populations. The STR loci (3-4 base pair repeat motifs), mapped in the cat genome relative to 579 coding loci and 255 STR loci, are well distributed across the 18 feline autosomes. All loci exhibit Mendelian inheritance in a multi-generation pedigree. Eleven loci that were unlinked and were highly heterozygous in cat breeds were selected for a forensic panel. Heterozygosity values obtained for the …

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Functional Response Of Six Indigenous Trichogrammatid Egg Parasitoids (Hymenoptera: Trichogrammatidae) In Kenya: Influence Of Temperature And Relative Humidity, Andrew Kalyebi, W. A. Overholt, F. Schulthess, J. M. Mueke, S. A. Hassan, S. Sithanantham Jan 2005

Functional Response Of Six Indigenous Trichogrammatid Egg Parasitoids (Hymenoptera: Trichogrammatidae) In Kenya: Influence Of Temperature And Relative Humidity, Andrew Kalyebi, W. A. Overholt, F. Schulthess, J. M. Mueke, S. A. Hassan, S. Sithanantham

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Laboratory tests were conducted to evaluate the functional responses of six species/strains of native Kenyan trichogrammatids using the factitious pyralid host, Corcyra cephalonica, under different temperature and relative humidity regimes. The objective was to identify promising species/strains for controlling the noctuid Helicoverpa armigera, a serious pest of vegetables in Kenya. The six species/strains of Trichogramma and Trichogrammatoidea represented collections from low (<700 m), mid (between 700 and 1200 m) and high (>1200 m) altitude locations. They were compared for parasitisation rates at six temperatures (10, 15, 20, 25, 30 and 35°C) and two relative humidity levels (40-50% and 70-80%), at five host egg densities (6, 12, 18, 24, and …

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The Presence Of Plasmodium Falciparum Gametocytes In Human Blood Increases The Gravidity Of Anopheles Gambiae Mosquitoes, Heather M. Ferguson, Louis C. Gouagna, Peter Obare, Andrew F. Read, Hamza Babiker, John Githure, John C. Beier Jan 2005

The Presence Of Plasmodium Falciparum Gametocytes In Human Blood Increases The Gravidity Of Anopheles Gambiae Mosquitoes, Heather M. Ferguson, Louis C. Gouagna, Peter Obare, Andrew F. Read, Hamza Babiker, John Githure, John C. Beier

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We conducted a field study in an area of endemic malaria transmission in western Kenya to determine whether mosquitoes that feed on gametocyte-infected blood but do not become infected have reduced or enhanced fecundity in comparison to mosquitoes fed on uninfected blood. Fifteen paired membrane-feeding experiments were conducted in which two strains of Anopheles gambiae mosquitoes were simultaneously fed on either Plasmodium falciparum-infected blood from children or uninfected control blood from adults. The presence of noninfecting gametocytes in blood increased the probability that An. gambiae would produce eggs after one blood meal by sixfold (odds ratio for control relative to …

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El Niño Causes Dramatic Outbreak Of Paederus Dermatitis In East Africa, Ingeborg M.C.J. Van Schayk, Ruben O. Agwanda, John I. Githure, John C. Beier, Bart G.J. Knols Jan 2005

El Niño Causes Dramatic Outbreak Of Paederus Dermatitis In East Africa, Ingeborg M.C.J. Van Schayk, Ruben O. Agwanda, John I. Githure, John C. Beier, Bart G.J. Knols

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An outbreak of Paederus sabaeus rove beetles in Kenya during the 1997-1998 El Niño resulted in a dramatic increase of vesicular dermatitis in its capital Nairobi. The beetle, popularly called ‘Nairobi Fly’, contains a potent toxic fluid that causes epidermolysis and acute conjunctivitis. A cross-sectional epidemiological study involving 1,208 Nairobi residents was conducted to determine the health impact of this outbreak. The results showed that one-third of the Nairobi population were infected during this period. The majority of the respondents reported lesions on exposed body parts above the shoulders. Disfiguring, painful blisters and skin rashes in and around the facial …

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Planting Date Effects On The Germinability And Seedling Vigor Of Abutilon Theophrasti Seeds, R E. Nurse, A Ditommaso, Ricardo A. Ramirez Dec 2004

Planting Date Effects On The Germinability And Seedling Vigor Of Abutilon Theophrasti Seeds, R E. Nurse, A Ditommaso, Ricardo A. Ramirez

Biology Faculty Publications

Abutilon theophrasti (Malvaceae) is a troublesome annual weed in many maize and soybean cropping systems of Canada and the United States. Seeds of A. theophrasti exhibit physical dormancy. Differences in the growing environment of parent plants may influence the germinability of seeds and vigour of seedlings produced by this species because of variation in resource allocation to seed development. Thus, the germinability of seeds and subsequent seedling vigour were examined for A. theophrasti plants grown in monoculture at a density of 4.2 plants m -2 under varying natural photoperiods in central New York State. Treatments were established by transplanting A. …

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Effect Of Agroecosystem Diversity On Natural Enemies Of Maize Stemborers In Coastal Kenya, C. A.O. Midega, C. K.P.O. Ogol, W. A. Overholt Dec 2004

Effect Of Agroecosystem Diversity On Natural Enemies Of Maize Stemborers In Coastal Kenya, C. A.O. Midega, C. K.P.O. Ogol, W. A. Overholt

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A study was conducted at Mtwapa in the northern coastal area of Kenya during the long and short rainy seasons of 1999 and 2000 to assess the benefits of agroecosystem diversification-through agroforestry and intercropping-on the activity of natural enemies of maize stemborers. Treatments consisted of maize and cowpea intercrops or maize monocrops planted within hedgerows of Leucaena leucocephala and Gliricidia sepium. The plots were mulched or unmulched and insecticide-treated or not. The maize stemborers encountered, in order of abundance, were Chilo partellus, Chilo orichalcociliellus and Sesamia calamistis. The egg parasitoids Trichogramma spp. and Telenomus spp. were recovered from stemborer eggs. …

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Laboratory Evaluation Of Some Eastern African Meliaceae As Sources Of Larvicidal Botanicals For Anopheles Gambiae, Mary Ndung'u, Baldwyn Torto, Bart G.J. Knols, Ahmed Hassanali Dec 2004

Laboratory Evaluation Of Some Eastern African Meliaceae As Sources Of Larvicidal Botanicals For Anopheles Gambiae, Mary Ndung'u, Baldwyn Torto, Bart G.J. Knols, Ahmed Hassanali

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Root bark extracts of five Meliaceae species (Turraea abyssinica Hochst., Turraea wakefeldii Oliv., Turraea mombassana Hiern ex C.DC., Trichilia roka (Forsk) Chiov. and Melia volkensii Guerke.) and different fractions thereof (following chloroform extraction and column chromatographic separation) were compared for their immediate toxicity and long-term effects on Anopheles gambiae Giles sensu stricto (Diptera: Culicidae). Larvicidal effects of the extracts appeared to be largely associated with limonoids of medium polarity with M. volkensii and T. mombassana extracts being more potent than those of the other Meliaceae. Long-term (6-8 days post-exposure) observations at lower doses showed that 100% cumulative mortality can be …

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Phlebotomine Sandflies (Diptera: Psychodidae) Collected In Mukusu, Machakos District, Kenya And Their Nocturnal Flight Activity, Eiko Kan, Christopher O. Anjili, Rajindar K. Saini, Toshitaka Hidaka, John I. Githure Nov 2004

Phlebotomine Sandflies (Diptera: Psychodidae) Collected In Mukusu, Machakos District, Kenya And Their Nocturnal Flight Activity, Eiko Kan, Christopher O. Anjili, Rajindar K. Saini, Toshitaka Hidaka, John I. Githure

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This is the first report on the nocturnal flight activity of the phlebotomine sandflies in the field by trap collection in Mukusu, Masinga, the kala-azar (visceral leishmaniasis in humans) area in Kenya. A total of 514 sandflies were collected with three different types of traps (sticky traps, CDC light traps and a goat-baited trap), and seven species of two genera (Sergentomyia and Phlebotomus) were identified. The number of Sergentomyia bedfordi Newstead individuals captured was the largest among these seven species. This suggests that S. bedfordi is the most common among the seven species in Mukusu. The result of the sticky …

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Performance Of Cotesia Flavipes (Hymenoptera: Braconidae) In Parasitizing Chilo Partellus (Lepidoptera: Crambidae) As Affected By Temperature And Host Stage, Nanqing Jiang, Mamoudou Sétamou, Adèle J. Ngi-Song, Charles O. Omwega Oct 2004

Performance Of Cotesia Flavipes (Hymenoptera: Braconidae) In Parasitizing Chilo Partellus (Lepidoptera: Crambidae) As Affected By Temperature And Host Stage, Nanqing Jiang, Mamoudou Sétamou, Adèle J. Ngi-Song, Charles O. Omwega

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The braconid larval parasitoid, Cotesia flavipes, is used as a biological control agent against the crambid Chilo partellus, a serious pest of cereal crops in eastern and southern Africa. We examined the survival, development parameters, and body growth patterns of the host and its parasitoid at different temperatures (22, 26, and 30°C) using third and fourth instars of Ch. partellus. For non-parasitized hosts, larval mortality tended to be highest at lowest temperature and for parasitized at third host instars only at highest temperature. Development time of Co. flavipes immatures significantly decreased with host instar and with temperature. Sex ratio of …

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The Development Of Plasmodium Falciparum In Experimentally Infected Anopheles Gambiae (Diptera: Culicidae) Under Ambient Microhabitat Temperature In Western Kenya, Bernard A. Okech, Louis C. Gouagna, Elizabeth Walczak, Ephantus W. Kabiru, John C. Beier, Guiyun Yan, John I. Githure Oct 2004

The Development Of Plasmodium Falciparum In Experimentally Infected Anopheles Gambiae (Diptera: Culicidae) Under Ambient Microhabitat Temperature In Western Kenya, Bernard A. Okech, Louis C. Gouagna, Elizabeth Walczak, Ephantus W. Kabiru, John C. Beier, Guiyun Yan, John I. Githure

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The effect of microhabitat temperature variation on the early development of Plasmodium falciparum in experimentally infected Anopheles gambiae s.s. (Diptera: Culicidae) was studied. Batches of mosquitoes were fed artificially on gametocyteamic blood obtained from human volunteers and then held in five environmental conditions described as: (1) incubator maintained at constant temperature of 28 ± 1°C as control; (2) temperature unregulated laboratory environment; (3) screen house; (4) grass thatched mud house and (5) corrugated iron roofed mud house. Both the grass and iron roofed mud houses were real houses found in the village communities around the ICIPE Research Centre in Mbita …

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Repellency Of Essential Oils Of Some Kenyan Plants Against Anopheles Gambiae, Maurice O. Omolo, Denis Okinyo, Isaiah O. Ndiege, Wilber Lwande, Ahmed Hassanali Oct 2004

Repellency Of Essential Oils Of Some Kenyan Plants Against Anopheles Gambiae, Maurice O. Omolo, Denis Okinyo, Isaiah O. Ndiege, Wilber Lwande, Ahmed Hassanali

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Five mosquito repellents have been identified from the essential oils of 6 plants growing in Kenya. These include (S)-(-)-cis-perillyl alcohol, (S)-(-)-cis-verbenol, (S)-(-)-cis-carveol, (S)-(-)-perillaldehyde, caryophyllene oxide and (S)-(-)-cis-perillyl alcohol. (S)-(-)-cis-perillyl alcohol and (S)-(-)-cis-verbenol were the most potent. Essential oils of six plants growing in Kenya were screened for repellent activities against Anopheles gambiae sensu stricto. The oils of Conyza newii (Compositeae) and Plectranthus marrubioides (Labiateae) were the most repellent (RD 50 = 8.9 × 10 -5 mg cm -2, 95% CI) followed by Lippia javanica (Verbenaceae), Lippia ukambensis (Verbenaceae), Tetradenia riparia, (Iboza multiflora) (Labiateae) and Tarchonanthus camphoratus (Compositeae). Eight constituents of …

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Influence Of Indoor Microclimate And Diet On Survival Of Anopheles Gambiae S.S. (Diptera: Culicidae) In Village House Conditions In Western Kenya, Bernard A. Okech, Louis C. Gouagna, Bart G.J. Knols, Ephantus W. Kabiru, Gerry F. Killeen, John C. Beier, Guiyun Yan, John I. Githure Sep 2004

Influence Of Indoor Microclimate And Diet On Survival Of Anopheles Gambiae S.S. (Diptera: Culicidae) In Village House Conditions In Western Kenya, Bernard A. Okech, Louis C. Gouagna, Bart G.J. Knols, Ephantus W. Kabiru, Gerry F. Killeen, John C. Beier, Guiyun Yan, John I. Githure

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The survival of female Anopheles gambiae s.s. mosquitoes inside two village house types (grass-thatched and iron-roofed) was studied in relation to diet and ambient indoor microclimatic conditions. Two batches of 20-30, 1-day-old laboratory-bred mosquitoes were maintained inside cages in the grass-thatched (n = 2) and iron-roofed (n = 2) houses and fed daily, one group on 10% glucose and the other on human blood. Throughout the experiments, indoor temperature and relative humidity of the houses were recorded, and mortality of mosquitoes monitored daily until all had died. The experiments were replicated thrice. There was no significant variation in the overall …

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