Environmental & Physical Sciences

Environmental & Physical Sciences Research Papers/Topics

Attraction response of adult Rhipicephalus appendiculatus and Rhipicephalus pulchellus (Acari: Ixodidae) ticks to extracts from Calpurnia aurea (Fabaceae)

Abstract: Experiments were carried out to investigate the response of two tick species Rhipicephalus pulchellus Gerstaker, 1873 and Rhipicephalus appendiculatus Neumann, 1901 to three different extracts (acetone, aqueous and oil) of the dried leaves of Calpurnia aurea (Aiton)Benth in both an inverted glass tube and a dual choice T-olfactometer. The oil extract at 50 and 100 mg/ml attracted 46.7% and 65.9% of R. appendiculatus, respectively, in the inverted glass tube assay, which was compara...

On the Occurrence of Bistrispinaria, Grass-breeding Fruit Flies (Diptera: Tephritidae) in Kenya, with an Addition to the Tephritid Checklist of Kakamega Forest.

Abstract: Identification of specimens from Malaise trap collections and rearings of tephritids from native and cereal grasses confirm the presence in Kenya of Bistrispinaria magniceps, B. fortis, and B. woodi, of which the latter two species are recorded for the first time. Including an earlier, but uncertain, record of B. atlas, all four species of Bistrispinaria, the only genus of Tephritidae in the Afrotropical region known to breed in grass stems, have now been recorded from Kenya. Infor...

Adaptation to and Small-Scale Rearing of Invasive Fruit Fly Bactrocera invadens (Diptera: Tephritidae) on Artificial Diet

Abstract: Larval rearing of Bactrocera invadens Drew, Tsuruta & White (Diptera: Tephritidae) on artiÞcial diet is described. The adaptation process for this insect, when moved from whole mango, Mangifera indica L., fruit rearing to artiÞcial diet based on wheat bran, took between three and Þve generations to reach the plateau of quality control parameters observed for rearing the insect on whole mango fruit. Small-scale rearing on wheat, Triticum aestivum L.-, or carrot, Daucus corata-bas...

Varroa-specific hygienic behaviour of Apis mellifera scutellata in Kenya.

Abstract: Varroa-specific hygienic behavior is a hereditary trait of honey bee (Apis mellifera), which supports resistance to Varroa destructor. This study investigated the response of Apis mellifera scutellata to Varroa-infested worker brood cells in Kenya, East Africa. Uncapping, removal of the brood, and disappearance of the introduced mite were recorded in a total of 690 cells into which live mites were introduced. We recorded a high proportion of untouched cells in controls (median, 80%...

Threshold temperatures and thermal requirements of black soldier fly Hermetia illucens: Implications for mass production.

Abstract: Efforts to recycle organic wastes using black soldier fly (BSF) Hermetia illucens into high-nutrient biomass that constitutes a sustainable fat (biodiesel) and high-quality protein ingredient in animal feeds have recently gained momentum worldwide. However, there is little information on the most suitable rearing conditions for growth, development and survivorship of these flies, which is a prerequisite for mass production technologies. We evaluated the physiological requirements f...

Transdisciplinary Research: Collaborative Leadership and Empowerment Towards Sustainability of Push–Pull Technology

Abstract: A transdisciplinary research approach requires that different scientists with their discipline-specific theories, concepts and methods find ways to work together with other societal players to address a real-life problem. In this study, the push–pull technology (PPT) was used as a boundary object to enable interactions among stakeholders across science-practice boundaries engaged in the control of stemborer pest in maize crops in Bako Tibe, Jimma Arjo and Yayu Woredas in Ethiopia...

Expression of Resistance in Amaranthus spp. (Caryophyllales: Amaranthaceae): Effects of Selected Accessions on the Behaviour and Biology of the Amaranth Leaf-Webber, Spoladea recurvalis (Lepi

Abstract: Abstract: Spoladea recurvalis F. is a major pest moth of amaranth (Amaranthus spp.) flowers worldwide,with a potential of causing complete foliage loss under severe outbreaks. Chemical insecticides are uneconomical for resource-poor farmers and pose health and environmental risks. Host plant resistance (HPR) to insects is an effective, economical and environmentally friendly alternative that is poorly understood and largely unexploited among traditional leafy vegetables. A total of...

Spatial Distribution of Bactrocera dorsalis and Thaumatotibia leucotreta in Smallholder Avocado Orchards along Altitudinal Gradient of Taita Hills and Mount Kilimanjaro

Abstract: Avocado (Persea americana) fruits are an important source of income and a nutritious food for small-scale growers and other stakeholders involved in farming along the Afrotropical highlands of Taita Hills and Mount Kilimanjaro in Kenya and Tanzania, respectively. Avocado fruits are infested by several insect pests, namely the Asian invasive fruit fly, Bactrocera dorsalis (Hendel) (Diptera:Tephritidae), and the false codling moth, Thaumatotibia leucotreta Meyrick (Lepidoptera: Tortr...

The Role of Intercropping Different Cereal Species in Controlling Lepidopteran Stemborers on Maize in Kenya

Abstract: The effects of mixed cropping systems containing maize, sorghum, millet and beans on infestations of cereals by lepidopteran stemborers and on associated parasitoids, as well as on yields and land equivalent ratios (LER) were assessed during four consecutive rainy seasons at two sites in the semi-arid eastern region of Kenya. Systems containing the non-host bean were more efficient in reducing pest densities than those with millet or sorghum only. Higher parasitism in diversified s...

Host recognition and acceptance behaviour in Cotesia sesamiae and C. flavipes (Hymenoptera: Braconidae), parasitoids of gramineous stemborers in Africa

Abstract: The host recognition and acceptance behaviour of two braconid larval parasitoids (Cotesia sesamiae and C. flavipes) were studied using natural stemborer hosts (i.e., the noctuid Busseola fusca for C. sesamiae, and the crambid Chilo partellus for C. flavipes) and a non-host (the pyralid Eldana saccharina). A single larva was introduced into an arena together with a female parasitoid and the behaviour of the wasp recorded until it either stung the larva or for a maximum of 5 min if i...

First report of a phytoplasma associated with Bermuda grass white leaf disease in Kenya

Abstract: Bermuda grass (=Star grass), Cynodon dactylon, is a perennial plant of the family Poaceae that is native to the African Savannah but is now widely distributed over many warm countries of the world (Marcone et al., 1997). C. dactylon plants were observed at five locations in Mbita and two locations in Bungoma areas of western Kenya showing symptoms similar to Bermuda grass white leaf (BGWL) disease, caused by a phytoplasma (Marcone et al., 1997). Affected grasses exhibited whitening...

Importance of contact chemical cues in host recognition and acceptance by the braconid larval endoparasitoids Cotesia sesamiae and Cotesia flavipes

Abstract: The ability of the congeneric braconid parasitoids Cotesia sesamiae (Cameron) and Cotesia flavipes Cameron to discriminate between stemborer larval cues upon contact was studied using their natural hosts,namely the noctuid Busseola fusca (Fuller) and the crambid Chilo partellus (Swinhoe), respectively, and the pyralid non-host Eldana saccharina (Walker). When the natural host larvae were washed in distilled water, parasitoid behavior was similar to that displayed when in contact wi...

Acceptability and Suitability of six Fruit Fly species (Diptera: Tephritidae) for Kenyan Strains of Psyttalia concolor (Hymenoptera: Braconidae)

Abstract: Host acceptability and suitability Psyttalia concolor (Sze´pligeti) is a koinobiont, larval parasitoid of tephritid fruit flies. Individuals of P. concolor were field-collected from coffee in the central highlands of Kenya, and cultured initially on editerranean fruit fly (medfly), Ceratitis capitata (Wiedemann). They were then examined for their ability to oviposit in and develop on five other tephritid species that are pests in Kenya. In addition to the medfly, acceptability for...

Salivary α-amylase of stem borer hosts determines host recognition and acceptance for oviposition by Cotesia spp. (Hymenoptera, Braconidae).

Abstract: Foraging insect parasitoids use specific chemical cues to discriminate between host and non-host species. Several compounds have been identified in “host location and acceptance.” However, nothing is known about the molecular variations in these compounds that could account for host-range differences between parasitoid species. In a previous study, it was shown that during the host-finding process, contact between the braconid Cotesia flavipes and its host is crucial, and that ...

Host Preference of Xanthopimpla Stemmator (Hymenoptera: Ichneumonidae) and its Reproductive Performance on Selected African Lepidopteran Stem borers

Abstract: The Asian pupal parasitoid, Xanthopimpla stemmator Thunberg, was imported into East Africa as a classical biological agent of lepidopteran cereal stem borers. Preference of X. stemmator females for four common borers of maize and sorghum; the crambid Chilo partellus (Swinhoe), the pyralid, Eldana saccharina Walker, and the noctuids, Busseola fusca Fuller and Sesamia calamistis Hampson, was investigated. Pre-adult experience of X. stemmator females did not influence choice of host. ...


421 - 435 Of 2180 Results