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Articles 2311 - 2340 of 2421

Full-Text Articles in Life Sciences

Physiological Responses And Central Nervous Projections Of Antennal Olfactory Receptor Neurons In The Adult Desert Locust, Schistocerca Gregaria (Orthoptera: Acrididae), B. S. Hansson, S. A. Ochieng, X. Grosmaitre S Anton, P. G.N. Njagi Jan 1996

Physiological Responses And Central Nervous Projections Of Antennal Olfactory Receptor Neurons In The Adult Desert Locust, Schistocerca Gregaria (Orthoptera: Acrididae), B. S. Hansson, S. A. Ochieng, X. Grosmaitre S Anton, P. G.N. Njagi

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Olfactory receptor neurons present in two morphological sensillum types on the male Schistocerca gregaria antenna were for the first time investigated physiologically when stimulated with behaviourally relevant odours. Neurons present in trichoid/basiconic sensilla showed clear excitatory responses to compounds present in the male-produced aggregation pheromone and also to a plant produced compound. Sensilla could be categorised physiologically according to the responses of their receptor neurons to the tested stimuli. Also receptor neurons present in sensilla coeloconica responded to aggregation pheromone components, but always in an inhibitory fashion. These neurons could, however, be excited by a plant produced compound and by …

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Prospects For Biological Control Of Livestock Ticks, Rhipicephalus Appendiculatus And Amblyomma Variegatum, Using The Entomogenous Fungi Beauveria Bassiana And Metarhizium Anisopliae, Godwin P. Kaaya, Esther N. Mwangi, Elizabeth A. Ouna Jan 1996

Prospects For Biological Control Of Livestock Ticks, Rhipicephalus Appendiculatus And Amblyomma Variegatum, Using The Entomogenous Fungi Beauveria Bassiana And Metarhizium Anisopliae, Godwin P. Kaaya, Esther N. Mwangi, Elizabeth A. Ouna

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Both Beauveria bassiana and Metarhizium anisopliae induced, approximately 30% mortalities in adult Rhipicephalus appendiculatus feeding on rabbits while M. anisopliae induced a mortality of 37% in adult Amblyomma variegatum. Both fungal species induced reductions in engorgement weights, fecundity, and egg hatchability in adult A. variegatum. M. anisopliae reduced fecundity by 94% in A. variegatum. Furthermore, B. bassiana reduced egg hatchability to 0%, while 11% of the infected females failed to lay eggs. In Zebu cattle naturally infested, with R. appendiculatus in the field, both B. bassiana and M. anisopliae induced high mortalities ranging from 76-85%, a remarkable reduction in fecundity …

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Reproductive Responses Of Iphiseius Degenerans And Neoseiulus Teke (Acari: Phytoseiidae) To Changes In The Density Of The Cassava Green Mite, Mononychellus Tanajoa (Acari: Tetranychidae), F. E. Nwilene, G. Nachman Jan 1996

Reproductive Responses Of Iphiseius Degenerans And Neoseiulus Teke (Acari: Phytoseiidae) To Changes In The Density Of The Cassava Green Mite, Mononychellus Tanajoa (Acari: Tetranychidae), F. E. Nwilene, G. Nachman

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We assessed the reproductive responses of adult female Iphiseius degenerans and Neoseiulus teke to increasing density of three stages of their prey, Mononychellus tanajoa, on cassava leaf discs under laboratory conditions. The oviposition rates increased with number of prey consumed per predator per day with a maximum of approximately two eggs per day for I. degenerans and four eggs per day for N. teke. The oviposition rate of N. teke was higher when consuming eggs than other prey stages. Neoseiulus teke was more efficient than I. degenerans in converting consumed prey into egg production. The data were adequately described by …

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Suitability Of Graminaceous Weed Species As Host Plants For Rice Leaffolders, Cnaphalocrocis Medinalis And Marasmia Patnalis, Z. R. Khan, M. L.P. Abenes, N. J. Fernandez Jan 1996

Suitability Of Graminaceous Weed Species As Host Plants For Rice Leaffolders, Cnaphalocrocis Medinalis And Marasmia Patnalis, Z. R. Khan, M. L.P. Abenes, N. J. Fernandez

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The suitability of 12 graminaceous weeds of ricefields as host plants for two rice leaffolders, Cnaphalocrocis medinalis (Guenée) and Marasmia patnalis Bradley (Lepidoptera: Pyralidae) was compared to a susceptible (IR36) and a moderately resistant (TKM6) rice variety in laboratory and greenhouse tests. Although rice was the most preferred host of the two leaffolder species, their responses to the test weeds varied significantly. Cnaphalocrocis medinalis responded better to most of the test weeds than did M. patnalis, suggesting a wider host range for C. medinalis. Third instar larval orientation and settling, and food consumption and assimilation of C. medinalis on Leersia …

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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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