Abstract: Pathogens causing African animal trypanosomiasis (AAT), the major livestock disease in subSaharan Africa, belong to the salivarian group of the African trypanosomes, which are transmitted by the bite of the tsetse fly (Glossina spec.). T. vivax, T. congolense and T. brucei brucei are major pathogens of cattle in particular, causing nagana, with dramatic socio-economic consequences for the affected regions. The parasites additionally have a huge reservoir of other livestock and wild...
Abstract: The thesis answers the general question of whether the quality of artificially reared insect species should be based on performance tests for intended use or whether quality should be based on a more holistic biological approach. The empirical research is carried out using the lepidopteran leafroller 'Cnephasia' jactatana (Walker). The thesis defines biological performance and quality in terms of the success of an insect population in survival and reproduction and regards the labor...
Abstract: The maize stalk borer Busseola fusca Fuller is a serious pest of maize in the highland areas of Kenya. In an effort to generate information that could be useful for integrated management of the pest, the main factors studied in the current investigations were its biology and ecology. Other studies involved its population patterns in relation to planting dates, crop losses caused by the pest and evaluation of crop loss assessment techniques used in estimation of losses due to ~. fus...
Abstract: Laboratory studies were conducted to determine the quantities of maize and sorghum stems consumed by larvae of C. partellus and C. orichalcociliel/us as an indication of the amount of damage caused by these species to cereal crops. Results revealed that larvae of C. partellus consumed a greater quantity of maize than C. orichalcociliel/us on a daily basis and throughout the larval lifetime. C. partellus also consumed more sorghum than C. orichalcociliellus on a daily basis, but bot...
Abstract: Busseala fusca (Lepidoptera:Noctuidae) is one of the most important insect pests of maize and sorghum in Africa, south of the Sahara. Last instar larvae of this species survive the dry season in the stalks and stubbles of their host plants by undergoing diapause. The present study was done with the main objective of investigating the involvement of the neuroendocrine system during the development of the last instar larvae with respect to non-diapause and diapause development. The m...
Abstract: Fruit flies (Diptera: Tephritidae) are notorious pests of horticultural crops, causing significant economic losses especially in the tropics. The conventional approaches utilized in controlling these pests including biological and chemical methods are relatively inefficient and targets mostly males, making it imperative to identify new Integrated Pest Management (IPM) tools that are effective and economically sustainable. To boost current efforts in fruit fly control, females shoul...
Abstract: An agglutinin with trypsin activity was purified from the midgut extracts of Glossina morsitans morsitans Westwood using a combination of ion exchange and affinity column chromatography procedures. The molecule had a native apparent molecular weight (Mr) of -65,700 and consisted of two non-covalently linked subunits; an a. subunit (-28,800 Da) and a B subunit (~35,700 Da). The B subunit was shown to have a glycosyl residue. This agglutinin had a bloodstream trypanosome agglutinatio...
Abstract: This study was conducted on Glossina fuscipes fuscipes, a riverine species of Central and Eastern Africa. It focuses on (i) colour preferences, (ii) landing and feeding behaviours on a host, the Nile monitor and (iii) on the trappability in odour- and colour-baited traps. Colour preferences were studied using electric screens in the field. Colours that were found most attractive were combined to make traps. These traps were tested as visual baits, compared to the standard biconical...
Description: A Thesis Submitted for the Degree of Doctor of Philosophy (Chemistry) of the University of Dar es Salaam
INTRODUCTION Sorghum bicolor Moench is one of the main staple food grains. The cereal forms part of staple food of the world's poorest people, particularly in the Semi-Arid Tropics (SAT). Elsewhere, especially in the developed world sorghum is used mainly as a fodder crop. The crop is grown on 42 million hectares in different parts of the world (FAO, 1980). Over 55% of the world’s sorghum production is in the SAT of which Africa and Asia contribute 65% (Swindle, 1982). In East Africa, sorgh...
Abstract: Stingless bees are important pollinators contributing significantly to biodiversity and food security. Stingless bees produce honey that has high medicinal value that fetches higher prices compared to the honey produced by honey bees (Apis mellifera). However,identification and classification of Afrotropical stingless bees, which is key and important for their domestication, still remains ambiguous and solely reliant on the use of morphological features. In this study, an integrati...
Abstract: This thesis describes the results of a study to assess the effect of ethnobotanical products on the behaviour of the brown ear tick Rhipicephalus appendiculatus, the main vector of East Coast fever in sub-Saharan Africa. Ethnoknowledge of the Bukusu people in western Kenya on tick control and management was evaluated to identify plants that affect livestock ticks, using participatory action research approaches. More than 150 plant species spread over 110 genera and 51 families were...
Abstract: In Locusta migratoria, vitellogenin (Vg) synthesis is normally induced by juvenile hormone (JH) only in adult females. Larval and adult female and male locusts were tested for inducibility of Vg synthesis by the synthetic JH analog, methoprene. While fourth and fifth larval stages of both sexes could be induced to synthesize Vg, adult males could not. Quant i tati ve assays showed the relative response in the order: adult female > fifth instar female > fifth instar male. Dur i ng t...
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...