Abstract: Lepidoperan stemborers are a major constraint to increasing the production of maize and sorghum under subsistence farming conditions in sub-Saharan Africa. Classical biological control is considered as the most cost-effective form of pest management but it has not attained the desired success rate. It has been postulated that one major reason for the failures in classical biological control is related to the genetic diversity of released_ individuals of natural enemies. The aim of ...
Abstract: Liriomyza (Diptera: Agromyzidae) leafminers are pests of economic importance to the production of horticultural crops in East Africa. In the scope of a classical biological control program in East Africa, two parasitoids Halticoptera arduine (Walker) (Hymenoptera: Pteromalidae) and Chrysocharis flacilla Walker (Hymenoptera: Eulophidae) were introduced from Peru. This dissertation aims to assess the performance and impact of the parasitoids in biological control of Liriomyza leafmin...
Abstract: Scanty information is available concerning the identity of the major pests of amaranth and African nightshades in Kenya and associated damage. The natural enemies of these pests have also not been studied in detail. In this PhD study, field survey to identify the major pests of amaranth and nightshades, their abundance, distribution, and damage in six regions in Kenya was conducted. The natural enemies for these pests present in the amaranth and nightshade fields in these regions w...
Abstract: Although it is widely accepted that plant resources play an important role in the biology of mosquito species, the preferred mosquito host plants in the natural habitats remain largely unknown. The persistence of mosquito-borne diseases and the re-emergence of others such as Zika have created the need for novel control strategies with plant feeding becoming a new focus for such strategies. Effective deployment of these new tools requires an accurate identification of preferred host...
Abstract: Malaria continues to be a major cause of morbidity and mortality in Kenya, with the transmission caused by mainly Anopheles gambiae funestus complexes. It is a serious threat to the social and economic advancement of the country. In this study, Field and laboratory studies were used to examine the primary factors responsible for regulating the aquatic stages of malaria vectors and the abundance and diversity of no-mosquito invertebrates in rice fields. The temporal and spatial prod...
Introduction: In Africa, there are two well known subspecies of the desert locust: the sahara subspecies, Schistocerca gregaria gregaria (Forskal) and the southern west subspecies, Schistocerca gregaria flaviventris (Burmeister). The sahara desert area, which is invaded by the S.g. gregaria is divided into three main regions: the north central region, south central and western regions.
Abstract: The sweet potato butterfly (Acraea acerata Hew.) has become an important pest on sweet potato in Southern Ethiopia in the last two decades. This thesis deals with its ecology and economic importance in Southern Ethiopia.The insect is indigenous to this area where it feeds on both native wild lpomoea species and the introduced sweet potato (L batatas). However, its perfonnance was better on the new host, sweet potato. The small A. acerata populations on the scattered patches of the ...
Abstract: Cowpea (Vigna unguiculata (L.) Walp) and common bean (Phaseolus vulgaris (L.)) are major sources of protein for human and animal consumption. Production of these crops is hampered by insect pests, especially the complex of brown spiny bugs of the genus Clavigralla (Hemiptera: Coreidae) which causes yield loss of up to 100% in various parts of Africa. The current practice of pesticide application to control these species is not efficient and has negative impacts on human health and ...
Abstract: Amaranths are African indigenous vegetables (AIVs) that are gaining popularity in several countries around the world due to their nutritional, medicinal and economic values. Insect pests are however a major challenge to optimum production of amaranths. The lepidopteran defoliator moth commonly known as Hawaiian beet webworm/amaranth leaf-webber, Spoladea recurvalis has been reported to be a major pest in amaranth fields, with the potential of causing complete defoliation under seve...
Abstract: Pathological potential of the fungus Beauveria bassiana Balsamo on the desert locust Schistocerca gregaria Forsk was evaluated with an aim to develop a mycoinsecticide as a supplement to the persistent chemical insecticides used for desert locust control in order to min imize the pollution in agroecosystems. Conidial suspension of B. bassiana when topically applied to locusts was found to be effoctive under 27.5 ± 2.50°C and 90% RH. Comparative stage susceptibility studies showed...
Abstract: D’après la FAO, il faudra nourrir 9 milliards de personnes en 2050 ce qui équivaudrait à augmenter de 70% la production actuelle. Une manière simple d’augmenter la production serait de limiter les pertes de rendement et de récolte en luttant contre les insectes. Il faudra donc produire plus mais il faut produire mieux. Les insecticides ont été et sont largement utilisés mais avec l’apparition de résistances, la pollution de l’environnement et l’impact sur la sant...
Abstract: Banana (Musa spp.) is an important food crop of the humid tropical lowland areas of the world. Banana production is beset by several problems, related to crop husbandry, selection of planting material, soils, diseases, and pests. Although more than 25 borers have been recorded on banana, the banana weevil Cosmopolites sordidus (Germar) (Curculionidae) is regarded as the major contributor to the general loss in plant vigour and yield. However, some banana cultivars have been found t...
Abstract: Grasses in the genus Brachiaria, commonly known as brachiaria are grown as a fodder crop in sub-Saharan Africa, with some genotypes being used in management of the spotted stemborer Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) through a habitat management strategy. Stemborer is a major insect pest of sorghum (Sorghum bicolor L. Moench) and maize (Zea mays L.) in Africa. However, utilization of brachiaria in cereal-livestock based farming systems in the region faces several bi...
Abstract: Host-seeking is an important component of mosquito vectorial capacity on which the success of the other behavioural determinants depends. Blood-seeking mosquitoes are mainly guided by chemical cues released by their blood hosts. This thesis describes results of a study that determined the effect of microorganisms – host skin bacteria as well as malaria parasites – on host-seeking behaviour of female Anopheles gambiae sensu stricto and An. arabiensis in Homabay county, western K...
Abstract: Mango, Mangifera indica L (Anacardiaceae) is an important tropical fruit providing opportunities for income generation and improvement of livelihoods of millions of farmers across Africa. However, fruit production is limited by several constraints; ranking high among these is the infestation by Tephritid fruit flies such as Bactrocera invadens and Ceratitis cosyra.