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Articles 1351 - 1380 of 1443

Full-Text Articles in Life Sciences

1,8-Cineole: An Attractant For The Banana Weevil, Cosmopolites Sordidus, Isaiah O. Ndiege, Willam J. Budenberg, Dalmas O. Otieno, Ahmed Hassanali Jan 1996

1,8-Cineole: An Attractant For The Banana Weevil, Cosmopolites Sordidus, Isaiah O. Ndiege, Willam J. Budenberg, Dalmas O. Otieno, Ahmed Hassanali

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1,8-Cineole was identified as one of the electrophysiologically active components of the volatiles from banana cultivars susceptible to the banana weevil. It was also shown to be an attractant for the banana weevil Comopolites sordidus in laboratory behavioural bioassays. The resistant cultivar did not contain 1,8-cineole. β-Phellandrene, which exhibited electrophysiological activity, but did not show any attraction to the banana weevil, was found only in the resistant banana cultivar.

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Volatile Infochemicals Used In Host And Host Habitat Location By Cotesia Flavipes Cameron And Cotesia Sesamiae (Cameron) (Hymenoptera: Braconidae), Larval Parasitoids Of Stemborers On Graminae, Adele J. Ngi-Song, William A. Overholt, Peter G.N. Njagi, Marcel Dicke, Jonathan N. Ayertey, Wilbert Lwande Jan 1996

Volatile Infochemicals Used In Host And Host Habitat Location By Cotesia Flavipes Cameron And Cotesia Sesamiae (Cameron) (Hymenoptera: Braconidae), Larval Parasitoids Of Stemborers On Graminae, Adele J. Ngi-Song, William A. Overholt, Peter G.N. Njagi, Marcel Dicke, Jonathan N. Ayertey, Wilbert Lwande

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Female Cotesia flavipes Cameron and Cotesia sesamiae (Cameron) were attracted to odors in a Y-tube olfactometer from uninfested maize (Zea mays L.), sorghum [Sorghum bicolor (L.)]. and napier grass (Pennisetum purpureum Schumach). In dual choice tests. Cotesia flavipes showed a preference for maize over sorghum, while maize and napier grass were equally attractive. In contrast, Cotesia sesamiae preferred volatiles from sorghum and napier grass over those from maize. The two parasitoids were significantly more attracted to maize infested with the stemborers, Chilo partellus (Swinhoe), Chilo orichalcociliellus Strand, Sesamia calamistis Hampson, and Busseola fusca (Fuller), than uninfested maize. In dual choice …

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Properties Of A Blood-Meal-Induced Midgut Lectin From The Tsetse Fly Glossina Morsitans, L. Abubakar, E. O. Osir, M. O. Imbuga Apr 1995

Properties Of A Blood-Meal-Induced Midgut Lectin From The Tsetse Fly Glossina Morsitans, L. Abubakar, E. O. Osir, M. O. Imbuga

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The properties of a blood-meal-induced lectin (agglutinin) from the midgut of Glossina morsitans capable of agglutinating Trypanosoma brucei were studied in vitro. The midgut homogenate from flies that had been fed twice had the highest agglutination activity, followed by that from the once-fed flies and that from the unfed insects. As compared with the bloodstream-form trypanosomes, a much lower concentration of the midgut homogenate was required for agglutination of the procyclic parasites. Furthermore, the agglutination process was specifically inhibited by D-glucosamine. Soybean trypsin inhibitor abrogated agglutination of the bloodstreamform parasites, whereas the procyclics were unaffected. The agglutination process was temperature-sensitive, …

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Purification And Characterization Of A Midgut Lectin-Trypsin Complex From The Tsetse Fly Glossina Longipennis, E. O. Osir, L. Abubakar, M. O. Imbuga Apr 1995

Purification And Characterization Of A Midgut Lectin-Trypsin Complex From The Tsetse Fly Glossina Longipennis, E. O. Osir, L. Abubakar, M. O. Imbuga

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A blood-meal-induced lectin (agglutinin) with proteolytic activity was isolated from midgut extracts of Glossina longipennis by a two-step procedure involving anion-exchange chromatography. It is a glycoprotein [native molecular weight (Mr, 61000±3000 da) composed of two noncovalently-linked subunits designated α (Mr, ∼27000 da) and β (Mr, ∼33000 da). The trypsin activity and the glycosyl residues were present on the α- and β-subunits, respectively. The native protein was capable of agglutinating both bloodstream-form and procyclic trypanosomes as well as rabbit red blood cells. This activity was strongly inhibited by D-glucosamine and weakly inhibited by N-acetyl-D-glucosamine. Similarly, soybean trypsin inhibitor abrogated agglutination of …

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Identification And Synthesis Of Sordidin, A Male Pheromone Emitted By Cosmopolites Sordidus, Josiane Beauhaire, Paul Henri Ducrot, Christian Malosse, Didier Rochat, Isaiah O. Ndiege, Dalmas O. Otieno Feb 1995

Identification And Synthesis Of Sordidin, A Male Pheromone Emitted By Cosmopolites Sordidus, Josiane Beauhaire, Paul Henri Ducrot, Christian Malosse, Didier Rochat, Isaiah O. Ndiege, Dalmas O. Otieno

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The diastereoselective synthesis of (1S*, 3R*, 5R*, 7S*) 2,8-dioxa 1-ethyl 3,5,7-trimethyl bicylo [3,2,1] octane 1d has been achieved using as key-step the regioselective Baeyer-Villiger reaction of 2,6-disubstituted cyclohexanone. It confirms the identification of a new male pheromone emitted by the banana weevil, Cosmopolites sordidus. The trivial name sordidin is proposed. © 1995.

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Products Derived From The Leaves Of Ocimum Kilimandscharicum (Labiatae) As Post-Harvest Grain Protectants Against The Infestation Of Three Major Stored Product Insect Pests, B. Jembere, D. Obeng-Ofori, A. Hassanali, G. N.N. Nyamasyo Jan 1995

Products Derived From The Leaves Of Ocimum Kilimandscharicum (Labiatae) As Post-Harvest Grain Protectants Against The Infestation Of Three Major Stored Product Insect Pests, B. Jembere, D. Obeng-Ofori, A. Hassanali, G. N.N. Nyamasyo

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The bioactivity of materials from the leaves of Ocimum kilimandscharicum was tested against Sitophilus zeamais Mots chulsky (Coleoptera: Curculionidae), Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae) and Sitotroga cerealella (Olivier) (Lepidoptera: Gelechiidae) in maize and sorghum grains in the laboratory. Exposure of adults of the three insect species to dried ground leaves and essential oil extract of O. kilimandscharicum induced 100% mortality after 48 h. Fresh and dried whole leaves were not toxic to Sitophilus zeamais or R. dominica. Grains treated with dried ground leaves and essential oil extract caused significant reductions in the number of progeny and survival rate of all …

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Linkage Relationships Among Loci Controlling Morphological Traits In Cowpea (Vigna Unguiculata (L.) Walp.), S. M. Githiri, P. M. Kimani, R. S. Pathak Jan 1995

Linkage Relationships Among Loci Controlling Morphological Traits In Cowpea (Vigna Unguiculata (L.) Walp.), S. M. Githiri, P. M. Kimani, R. S. Pathak

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Linkage among loci controlling various morphological traits in cowpea were determined using F2 progenies. Data were collected on individual plants of four crosses segregating for several loci. Recombination estimates between the following pairs of loci were as follows: Sw (swollen vs normal stem base)-Fbc (cream vs green flower buds) (41±4.8%), Pus(purple vs green stems)-Cbr (cocoa-brown vs straw-yellow dry pods) (31±5.7%), Pup(purple vs green immature pods)-Cbr (30±5.7%), Pus-Pup (4±1.5%), Ndt (non-determinate vs determinate)-Pd (peduncle colour) (26±2.8%), Ndt-Hg (semi-erect vs erect plant type) (26±2.8%), Pt(purple vs green pod tips)-Bk (greyish-black vs straw-yellow dry pods) (19±2.4%) and Hg-Bpd (normal vs branching peduncle (24±9.5%). …

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Importance Of Adult Food Sources To Host Searching Of The Larval Parasitoid Microplitis Croceipes, Keiji Takasu, W. J. Lewis Jan 1995

Importance Of Adult Food Sources To Host Searching Of The Larval Parasitoid Microplitis Croceipes, Keiji Takasu, W. J. Lewis

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We conducted field experiments to determine the effects of food availability and parasitoid hunger on the searching behavior of Microplitis croceipes (Cresson) (Braconidae; Hymenoptera) in small corn and soybean plots. In both corn and soybean plots where food was not available, females which were well-fed prior to release parasitized more hosts than unfed females. Well-fed females spent more time hovering and less time searching undamaged leaves than did unfed females. Because hovering time is an indicator of active host searching, the better parasitization rate by well-fed females can be explained by the greater proportion of time spent in active host …

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Limonoids From Turraea Floribunda, Baldwyn Torto, Michael D. Bentley, Barbara J.W. Cole, Ahmed Hassanali, Fu Yung Huang, Leslie Gelbaum, Donald G. Vanderveer Jan 1995

Limonoids From Turraea Floribunda, Baldwyn Torto, Michael D. Bentley, Barbara J.W. Cole, Ahmed Hassanali, Fu Yung Huang, Leslie Gelbaum, Donald G. Vanderveer

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Extracts of the root bark of Turraea floribunda have yielded four new limonoids of the havanensin class: 28-nor-4α-carbomethoxy-11β-acetoxy-12α-(2-methylbutanoyloxy)-14,15-deoxyhavanensin-1,7-diacetate; 28-nor-4α-carbomethoxy-11β-hydroxy-12α-(2-methylbutanoyloxy)-14,15-deoxyhavanensin-1,7-diacetate; 18-nor-4α-carbomethoxy-11β-acetoxy-12α-(2-methylbutanoyloxy)-14,15-deoxyhavanensin-1-acetate; and 28-nor-4α-carbomethoxy-7-deoxy-7-oxo-11β-acetoxy-12α-(2-methylbutanoyloxy)-14,15-deoxyhavanensin-1-acetate. The structures were determined by spectroscopic methods. The structure for the first of these compounds was also confirmed by X-ray diffraction methods. © 1995.

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Lipophorin And Apolipophorin-Iii In Solitary And Gregarious Phases Of Schistocerca Gregaria, Dorington O. Ogoyi, Ellie O. Osir, Norah K. Olembo Jan 1995

Lipophorin And Apolipophorin-Iii In Solitary And Gregarious Phases Of Schistocerca Gregaria, Dorington O. Ogoyi, Ellie O. Osir, Norah K. Olembo

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Lipophorin was isolated from the hemolymph by KBr density gradient ultracentrifugation. Apolipophorin-III (apoLp-III) was isolated from low-density lipophorin (LDLp). High-density lipophorin (HDLp) (Mr ∼-620,000) consisted of two apoproteins, apoLp-I (Mr ∼-224,000) and apoLp-II (Mr ∼-81,000). Isolated apoLp-III (Mr ∼-20,000) had two isoforms in non-denaturing gels. Injection of adipokinetic hormone-I resulted in the formation of LDLp in both locust phases. Lipid content of HDLp was estimated at 48.4% and 51.8% for solitary and gregarious locusts, respectively. In LDLp, lipids constituted 59.8% and 57.1% for gregarious and solitary locusts, respectively. The results suggest that the gregarious locusts were more efficient in the …

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Evidence Of The Establishment Of Cotesia Flavipes (Hymenoptera: Braconidae) In Continental Africa, C. O. Omwega, S. W. Kimani, W. A. Overholt, C. K.P.O. Ogol Jan 1995

Evidence Of The Establishment Of Cotesia Flavipes (Hymenoptera: Braconidae) In Continental Africa, C. O. Omwega, S. W. Kimani, W. A. Overholt, C. K.P.O. Ogol

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Cotesia flavipes Cameron has been released several times in Africa for biological control of gramineous stem borers. Establishment has been reported on the Indian Ocean islands of Mauritius, Réunion and Madagascar, however, several attempts to introduce C. flavipes into continental Africa are reported to have failed. Recently, several cocoon masses of C. flavipes were recovered from south-western Kenya where the parasitoid was never released. Identifications of the parasitoids from south-western Kenya were based on morphological characters, allozyme frequencies, and mating experiments with laboratory populations of C. flavipes. It is hypothesized that C. flavipes became established from individuals escaping from a …

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Semiochemicals From Froth Of Egg Pods Attract Ovipositing Female Schistocerca Gregaria, R. K. Saini, M. M. Rai, A. Hassanali, J. Wawiye, H. Odongo Jan 1995

Semiochemicals From Froth Of Egg Pods Attract Ovipositing Female Schistocerca Gregaria, R. K. Saini, M. M. Rai, A. Hassanali, J. Wawiye, H. Odongo

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A chemical signal, originating from the froth of egg pods attracts gravid female Schistocerca gregaria (Orthoptera: Acrididae) to common egg laying sites. Behavioural experiments indicated that females preferred to oviposit in moist sand contaminated with froth (60% egg laying vs 34% in sterilized sand). Extracts and volatiles collected from froth were also attractive to gravid females. In fact, froth volatiles elicited the strongest egg laying response (80% egg laying). Results with froth extracts obtained by sequential extraction with solvents of increasing polarity suggest that both non-polar and polar compounds are involved in the attraction of gravid females. Electroantennogram recordings with …

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Biosystematics Of The Cotesia Flavipes Complex (Hymenoptera: Braconidae): Interspecific Hybridization, Sex Pheromone And Mating Behaviour Studies, Susan W. Kimani, William A. Overholt Jan 1995

Biosystematics Of The Cotesia Flavipes Complex (Hymenoptera: Braconidae): Interspecific Hybridization, Sex Pheromone And Mating Behaviour Studies, Susan W. Kimani, William A. Overholt

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Mating behaviour, sex pheromone attraction and reciprocal breeding of Cotesia flavipes Cameron (Hymenoptera: Braconidae), C. sesamiae (Cameron) and C. chilonis (Matsumura) were studied. These three putative species comprise the Cotesia flavipes complex. Wing fanning and antennal vibration were the initial courtship signals from the males. Antennal stroking by the male was also an important contact signal and a prerequisite to successful mounting and copulation. Interspecific crosses revealed that males of C. flavipes exhibited courtship behaviour, and mounted and copulated with females of C. chilonis and C. sesamiae; the males transferred sperm but progeny from these crosses did not include females. …

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Effect Of Pubescence In Cowpea Resistance To The Legume Pod Borer Maruca Testulalis (Lepidoptera: Pyralidae), S. Oghiakhe Jan 1995

Effect Of Pubescence In Cowpea Resistance To The Legume Pod Borer Maruca Testulalis (Lepidoptera: Pyralidae), S. Oghiakhe

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Pubescence (trichomes) in wild and cultivated cowpeas, Vigna vexillata and V. unguiculata, adversely affected oviposition, mobility, and food consumption and utilisation by the legume pod borer, Maruca testulalis (Geyer), in tests conducted with TVnu 72 (wild, highly resistant and highly pubescent), TVu 946 (semi-wild, moderately resistant and pubescent) and IT82D-716 (cultivated, highly susceptible and pubescent). In free-choice and no-choice tests, significantly (P < 0.05) fewer eggs were laid on 3-week-old potted plants of TVnu 72, the highly pubescent and wild species; this species also received fewer eggs on abaxial and adaxial leaf surfaces. Ovipositional activity on stipules, stem, branches, terminal shoots, adaxial and abaxial leaf surfaces of the susceptible cultivar, IT82D-716 was higher (P < 0.05) than on TVu 946 and TVnu 72. More eggs were laid on the abaxial surfaces than on the adaxial surfaces of leaves for all tests conducted, except for the TVnu 72 no-choice test. Significant negative correlations (r = -0.99** and r = -0.99**) were found between mean number of eggs laid and length and density of non-glandular trichomes. There was a significant negative correlation (r = -0.99**) between larval velocity and length of non-glandular trichomes on pod surface. Similarly, significant negative correlations (r = -0.85* and -0.89*) were found between larval velocity and density and length of non-glandular trichomes on leaf surface. Pods of IT82D-716 and TVnu 72 were the most - and least - preferred for settling by larvae of M. testulalis, respectively. There was a significant positive correlation (r = 0.99**) between larval penetration time on pods and length of non-glandular trichomes. Weight loss, number of feeding punctures and number of larvae on whole pods of TVnu 72 were lower and significantly different (P < 0.05) from IT82D-716 and TVu 946. This study showed that it would be advantageous to use TVnu 72 in a breeding programme to incorporate pubescence into high-yielding commercial cultivars for resistance against M. testulalis and possibly other major pests. © 1995.

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Proximity Of Release Points Of Pheromone Components As A Factor Confusing Males Of The Spotted Stem Borer, Chilo Partellus, Approaching The Trap, Slawomir A. Lux, Ahmed Hassanali, Wilber Lwande, Florence N. Njogu Aug 1994

Proximity Of Release Points Of Pheromone Components As A Factor Confusing Males Of The Spotted Stem Borer, Chilo Partellus, Approaching The Trap, Slawomir A. Lux, Ahmed Hassanali, Wilber Lwande, Florence N. Njogu

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The effect of proximity of the release points of the two pheromone components (Z)-11-hexadecenal and (Z)-11-hexadecen-1-ol of the spotted stem borer, Chilo partellus (Lepidoptera: Pyralidae) on behavior of the males and on trapping efficiency was investigated. Separating the dispensers of the two components in the trap by a mere 3 cm resulted in a threefold decrease in trap performance, compared to very close release of the components. The result is attributed to possible distortion of the pheromone signal, resulting in confused behavior of C. partellus males in the vicinity of the trap. The ethological and practical implications of the phenomenon …

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Fecal Volatiles As Part Of The Aggregation Pheromone Complex Of The Desert Locust, Schistocerca Gregaria (Forskal) (Orthoptera: Acrididae), Daniel Obeng-Ofori, Baldwin Torto, Peter G.N. Njagi, Ahmed Hassanali, Habert Amiani Aug 1994

Fecal Volatiles As Part Of The Aggregation Pheromone Complex Of The Desert Locust, Schistocerca Gregaria (Forskal) (Orthoptera: Acrididae), Daniel Obeng-Ofori, Baldwin Torto, Peter G.N. Njagi, Ahmed Hassanali, Habert Amiani

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Olfactometric bioassays showed that nymphs of crowded desert locusts, Schistocerca gregaria, aggregated in response to volatiles derived from their feces and to volatiles emitted from the feces of young adults, but were indifferent to volatiles emitted by older adult feces. On the other hand, young and older adults were not only responsive to their own fecal volatiles but also cross-responsive to each other's and that of the nymphs. Charcoal-trapped volatiles from the feces and synthetic blends of the fecal volatiles also elicited similar responses. Young adults responded moderately to a blend of nymphal volatiles and those derived from nymphal feces. …

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Natural Attraction Of Livestock Ticks By The Leaves Of A Shrub, S. M. Hassan, O. O. Dipeolu, M. M. Malonza Jun 1994

Natural Attraction Of Livestock Ticks By The Leaves Of A Shrub, S. M. Hassan, O. O. Dipeolu, M. M. Malonza

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During examination of leaves of different plants on Rusinga Island, Kenya, ticks were commonly found on the leaves of a plant identified as Acalypha fruticosa Forsk. var. villosa Hutch (Euphorbiaceae). Larvae of Rhipicephalus appendiculatus were the predominant ticks encountered, found quiescent on the undersurface of the leaves. Laboratory investigations showed that significant numbers of ticks were attracted by odours from this plant. It was concluded that the leaves of A. fruticosa are attractive to this tick and have potential for use as a trap to control ticks. © 1994 Centre for Tropical Veterinary Medicine.

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Dynamics Of Host Blood Effects In Glossina Morsitans Sspp. Infected With Trypanosoma Congolense And T. Brucei, Reardon O. Olubayo, Steve Mihok, Eli Munyoki, Leonard H. Otieno Mar 1994

Dynamics Of Host Blood Effects In Glossina Morsitans Sspp. Infected With Trypanosoma Congolense And T. Brucei, Reardon O. Olubayo, Steve Mihok, Eli Munyoki, Leonard H. Otieno

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The pattern of infection in Glossina morsitans morsitans and G. m. centralis membrane-fed on eland, buffalo or goat blood mixed with Trypanosoma congolense or T. brucei was studied from day 1 to day 10. Tsetse were initially permissive vectors, with most flies harbouring infections of 104-105 parasites on day 3. However, after a second blood meal on day 3, flies cleared many infections with G. m. morsitans clearing more infections than G. m. centralis. Infective feeds of goat blood consistently increased final infection rates by limiting the number of infections lost between days 3 and 6. In further experiments with …

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Trypanosoma Simiae In The White Rhinoceros (Ceratotherium Simum) And The Dromedary Camel (Camelus Dromedarius), Steve Mihok, Erich Zweygarth, Eli N. Munyoki, John Wambua, Richard Kock Jan 1994

Trypanosoma Simiae In The White Rhinoceros (Ceratotherium Simum) And The Dromedary Camel (Camelus Dromedarius), Steve Mihok, Erich Zweygarth, Eli N. Munyoki, John Wambua, Richard Kock

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Trypanosoma simiae was identified as the cause of a disease outbreak in dromedary camels (Camelus dromedarius) introduced to Tsavo East National Park, confirming the susceptibility of camels to this pathogen. T. simiae was also isolated from a new host, the white rhinoceros (Ceratotherium simum) through xenodiagnosis with a susceptible tsetse species (Glossina morsitans centralis). A white rhinoceros showed some evidence of anaemia and lymphopaenia when harbouring T. simiae, but did not suffer any long-term health effects. © 1994.

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Detection Of Trypanosome Infections In The Saliva Of Tsetse Flies And Buffy-Coat Samples From Antigenaemic But Aparasitaemic Cattle, P. A.O. Majiwa, R. Thatthi, S. K. Moloo, J. H.P. Nyeko Jan 1994

Detection Of Trypanosome Infections In The Saliva Of Tsetse Flies And Buffy-Coat Samples From Antigenaemic But Aparasitaemic Cattle, P. A.O. Majiwa, R. Thatthi, S. K. Moloo, J. H.P. Nyeko

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Relatively simple protocols employing non-radioactive DNA probes have been used for the detection of African trypano-somes in the blood of mammalian hosts and the saliva of live tsetse flies. In combination with the polymerase chain reaction (PCR), the protocols revealed trypanosomes in buffy-coat samples from antigenaemic but aparasitaemic cattle and in the saliva of live, infected tsetse flies. Furthermore, the protocols were used to demonstrate concurrent natural infections of single tsetse flies with different species of African trypanosomes. © 1994, Cambridge University Press. All rights reserved.

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Interrelationship Among Chilo Partellus (Swinhoe) Damage Parameters And Their Contribution To Grain Yield Reduction In Maize (Zea Mays L.), S. O. Ajala, K. N. Saxena Jan 1994

Interrelationship Among Chilo Partellus (Swinhoe) Damage Parameters And Their Contribution To Grain Yield Reduction In Maize (Zea Mays L.), S. O. Ajala, K. N. Saxena

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Understanding the relationship among the spotted stem borer (Chilo partellus) damage parameters and grain yield reduction on maize (Zea mays L.) will aid in elucidation of the most important damage parameters that reduce yield, and may consequently lead to development of functional criteria to quantify tolerance and resistance. Correlations, stepwise multiple regressions and path coefficient analyses were used to study the interrelationship among the three damage parameters (foliar lesions, dead heart and stem tunnelling) and their contribution to grain yield reduction using three separate groups of genotypes in trials conducted between 1990 and 1991. Foliar lesions and stem tunnelling were …

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Effects Of Neem Seed Derivatives On Brown Planthopper Symbiotes, S. Raguraman, R. C. Saxena Jan 1994

Effects Of Neem Seed Derivatives On Brown Planthopper Symbiotes, S. Raguraman, R. C. Saxena

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Populations of intracellular symbiotes declined significantly in brachypterous females of the brown planthopper, Nilaparvata lugens (Stål), which were stressed during nymphal development by caging them on IR20 rice plants treated with 3% neem oil, 5% neem seed kernel aqueous extract, or 10% neem cake aqueous extract. In addition, nymphs grew poorly and symbiote populations in prospective females declined, when reared on rice plants grown in soil treated with neem cake; this indicates systemic action of bioac-tive neem constituents. Addition of custard-apple oil to neem oil did not enhance the inhibitory effects. The effects of neem derivatives on the symbiotes may …

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Isolation Of Trypanosoma Spp. From Wild Tsetse Flies Through Procyclic Expansion In Glossina Morsitans Centralis, Steve Mihok, Eli N. Munyoki, Freddie Masaninga, Paul N. Ndegwa, Reardon O. Olubayo Jan 1994

Isolation Of Trypanosoma Spp. From Wild Tsetse Flies Through Procyclic Expansion In Glossina Morsitans Centralis, Steve Mihok, Eli N. Munyoki, Freddie Masaninga, Paul N. Ndegwa, Reardon O. Olubayo

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Procyclic trypanosomes from wild tsetse flies were membrane-fed to Glossina morsitans centralis in order to develop an optimal technique for propagating field isolates. A 70% success rate was achieved in isolating Trypanosoma simiae and a variety of genotypes of T. congolense originating from G. pallidipes, G. brevipalpis and G. swynnertoni. Parasites matured into forms infective for mammals, and could be maintained by passage of gut forms to new groups of flies. In experiments with laboratory stocks, we also passaged immature gut infections of T. congolense and T. brucei from various tsetse species to G. m. centralis. The optimal technique was …

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Distribution And Sampling Of Chilo Partellus (Lepidoptera: Pyralidae) In Maize And Sorghum On The Kenya Coast, W. A. Overholt, K. Ogedah, P. M. Lammers Jan 1994

Distribution And Sampling Of Chilo Partellus (Lepidoptera: Pyralidae) In Maize And Sorghum On The Kenya Coast, W. A. Overholt, K. Ogedah, P. M. Lammers

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The seasonal occurrence and spatial distribution of the crambine stem borer, Chilo partellus (Swinhoe) were investigated in maize, Zea mays, and sorghum, Sorghum bicolor, fields at the Kenya coast. During the vegetative growth stage, small-sized larvae were typically found behind leaf sheaths and in whorls in maize and sorghum. In reproductive and senescent maize, small-sized larvae were also found feeding in ears. Later immature life stages were located predominantly in stems in sorghum, and in the stems and ears in maize. Density and variance estimates of small, medium-, and large-sized larvae and pupae in maize and sorghum were fitted to …

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Parasitism Of Amblyomma Variegatum By A Hymenopteran Parasitoid In The Laboratory, And Some Aspects Of Its Basic Biology, Esther N. Mwangi, Godwin P. Kaaya, Suliman Essuman, Mark G. Kimondo Jan 1994

Parasitism Of Amblyomma Variegatum By A Hymenopteran Parasitoid In The Laboratory, And Some Aspects Of Its Basic Biology, Esther N. Mwangi, Godwin P. Kaaya, Suliman Essuman, Mark G. Kimondo

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Unfed Amblyomma variegatum F. nymphs were experimentally infected in the laboratory with a hymenopteran parasitoid, Ixodiphagus hookeri (Howard). The parasitoid was originally obtained from ticks collected from cattle in the Trans-Mara area of Kenya where it naturally infects 50% of A. variegatum nymphs. In the field, nymphs collected from cattle were found to be infected, but not those collected from grass. The optimum temperature for emergence of parasitoids from the nymphs in the laboratory was 28°C, but emerged parasitoids were more active and survived longer at 22°C. There was a higher proportion of parasitoid nonemergence from laboratory-infected than from the …

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Grain Yield Losses In Maize (Zea Mays L.) Genotypes In Relation To Their Resistance Against Chilo Partellus (Swinhoe) Infestation At Anthesis, Harish Kumar, Gershon O. Asino Jan 1994

Grain Yield Losses In Maize (Zea Mays L.) Genotypes In Relation To Their Resistance Against Chilo Partellus (Swinhoe) Infestation At Anthesis, Harish Kumar, Gershon O. Asino

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Resistance/susceptibility of 12 maize genotypes to stem borer Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) was measured under artificial infestation at the time of anthesis during the short rainy seasons of 1989/90 and 1990/91. The maize genotypes tested were Inbred A (Kenya), Pwani hybrid (Kenya), Hybrid 511 (Kenya), ICZ2-CM (CIMMYT), MBR-8637 (CIMMYT), MBR-8650 (CIMMYT), MBR-8668 (CIMMYT), Poza Rica 7832 (CIMMYT), Mp704 (USDA), Katumani Composite B (Kenya), Bulk CG 4141 (Zambia), and MMV 400 (Zambia). Under low infestation (50-60 eggs per plant), the differences between susceptible and resistant genotypes in terms of stalk damage or grain damage were not apparent, whereas under high …

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Studies On The Maturation-Accelerating Pheromone Of The Desert Locust Schistocerca Gregaria (Orthoptera: Acrididae), Hassane Mahamat, Ahmed Hassanali, Hezekiel Odongo, Baldwyn Torto, El Sayeed El-Bashir Sep 1993

Studies On The Maturation-Accelerating Pheromone Of The Desert Locust Schistocerca Gregaria (Orthoptera: Acrididae), Hassane Mahamat, Ahmed Hassanali, Hezekiel Odongo, Baldwyn Torto, El Sayeed El-Bashir

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The accelerating effect of mature males of the desert locust, Schistocerca gregaria, on the maturation of immature male and female conspecifics was confirmed. The onset of sexual activity was found to correlate with yellowing of the male insects. Using the colour as an indicator of maturation, the maturation-hastening effect of an hexane extract from mature males was also confirmed. Likewise, volatiles from mature males placed in the upper storey of a two-chamber bioassay system (no visual or tactile contact possible) and charcoal-trapped volatiles from the mature males also induced accelerated maturation in recipient males placed in the lower storey. GC …

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Semiochemicals From Anal Exudate Of Larvae Of Tsetse Flies Glossina Morsitans Morsitans Westwood And G. Morsitans Centralis Machado Attract Gravid Females, David E. Leonard, R. K. Saini Sep 1993

Semiochemicals From Anal Exudate Of Larvae Of Tsetse Flies Glossina Morsitans Morsitans Westwood And G. Morsitans Centralis Machado Attract Gravid Females, David E. Leonard, R. K. Saini

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Tsetse flies (Diptera: Glossinidae:Glossina) mature their offspring in utero, giving birth to mature larvae that burrow into soil and pupariate. During the hot dry seasons, puparia of some species of tsetse are aggregated in areas of deep shade in dense thickets. We have confirmed the presence of a semiochemical from the prepupariation excretions of larvae of Glossina morsitans morsitans Westwood and report a similar semiochemical in Glossina morsitans centralis Machado. These semiochemicals are attractive to gravid females and result in the aggregation of puparia. Behavioral studies with G. m. centralis showed that a higher percentage of females larviposited over moist …

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Evidence For Volatile Male-Produced Pheromone In Banana Weevil Cosmopolites Sordidus, William J. Budenberg, Isaiah O. Ndiege, Florence W. Karago Sep 1993

Evidence For Volatile Male-Produced Pheromone In Banana Weevil Cosmopolites Sordidus, William J. Budenberg, Isaiah O. Ndiege, Florence W. Karago

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Females of the banana weevil, Cosmopolites sordidus, were attracted to and made longer visits to live conspecific males, trapped volatiles from males, and dissected male hindguts in a still-air olfactometer. Male weevils were attracted to volatiles trapped from males and made longer visits to live males and volatiles from males. Live females, collected volatiles from females and female hindguts, elicited small or no behavioral responses from either sex. Electroantennogram (EAG) responses from both male and female antennae were elicited by collected volatiles from males and by dichloromethane extracts of male hindguts and bodies but not by surface washes of males. …

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Evidence For Mediation Of Two Releaser Pheromones In The Aggregation Behavior Of The Gregarious Desert Locust, Schistocerca Gregaria (Forskal) (Orthoptera: Acrididae), Daniel Obeng-Ofori, Baldwyn Torto, Ahmed Hassanali Aug 1993

Evidence For Mediation Of Two Releaser Pheromones In The Aggregation Behavior Of The Gregarious Desert Locust, Schistocerca Gregaria (Forskal) (Orthoptera: Acrididae), Daniel Obeng-Ofori, Baldwyn Torto, Ahmed Hassanali

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The response of nymphal and adult gregarious phase desert locust, Schistocerca gregaria, to a choice of two columns of air, one permeated with airborne volatiles emanating from nymphs or adults and the other untreated, was investigated in a single-chamber bioassay arena. The nymphs, whether released individually or in groups, preferred to be within the precinct of the air column treated with airborne volatiles of the nymphs but were indifferent to volatiles of the adults. Conversely, older adults responded only to their own volatiles but not to those of the nymphs or young adults. The young adults were responsive only to …

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