BYABAGAMBI SIMON
MSc. Crop Science (M.U.K)
Submitted to the School of Post Graduate Studies in Partial Fulfillment for the Award of Doctor of Crop Science Degree of Makerere University

Overall Objective
Determine the tri-trophic interactions between predators, parasitoids and lepidopteran pests in cotton that are likely to be affected by the introduction of Bt cotton.
Specific Objectives
 To determine the relative abundance of target (“defined cotton pests”) and
Nontarget arthropods in cotton and other identified host crops
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To determine the tri-trophic interactions between predators, parasitoids and lepidopteran pests in the different cotton cultivars in Uganda.
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To determine the impact of different surrogate diets (including but not restricted to Bt media) on the bionomics of the major natural enemies of cotton lepidopteran pests under laboratory conditions.
Hypotheses
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Different cropping systems and agro-ecological zones in Uganda have varying species of cotton-associated arthropod pests and natural enemies that are likely to be affected by Bt cotton.
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Cotton cultivars grown in the different agro ecological zones in Uganda affect predators/parasitoids of cotton Lepidopteran pest in their host finding/accepting (feeding) and oviposition preference.

Natural enemies of the target lepidopteran cotton pests reared on Bt containing diet will have a lower fitness than those that consume a diet without Bt toxins.
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Significance and Expected output
Baseline data and information on tri-trophic interactions between predators, parasitoids and lepidopteran pests in cotton that are likely to be affected by the introduction of Bt cotton will be generated and this will subsequently help in decision making with respect to risk assessment and management of transgenic cotton in Uganda.
MATERIALS AND METHODS
The study is being conducted in stages starting with a survey. The results obtained from the survey will then be used as a guide to laboratory and field trials to be conducted.
Relative Abundance of Target (“defined cotton pests”) and Nontarget
Arthropods in Cotton, other identified host crops
The Bt toxins are targeted to control mainly Lepidoptera, and Coleopteran pests.
In this study, members of Lepidoptera and coleopteran that are known to be major pests of cotton are being considered as the target arthropods, while members of the same groups of insects, which are not pests of cotton, are considered as the non-target arthropods.
Data for characterization of the relative abundance of target and nontarget arthropods in cotton cropping systems is being collected in three major cottongrowing regions in Uganda so as to address the hypothesis that different cropping systems and agro-ecological zones in Uganda have varying species of cotton-associated arthropod pests.
The study is being carried out in three different ecological regions of Kasese
(Southwestern Uganda), Palisa (Eastern Uganda) and Lira (Northern Uganda).
In each of the three districts, two cotton major growing sub counties were selected. In each of the two sub counties, eight farmer fields are being surveyed.
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The selected farmer fields will be surveyed nine times; twice in the vegetative stage, thrice in the flowering and boll formation stages respectively and once just before harvesting. In addition, other crops in the neighborhood of the cotton fields (farmers’) and non-crops (native plants and various weeds) are being sampled for the target and non-target pests. The surveys will be conducted in two growing seasons. Different sampling methods are being employed to cater for the different categories of pests and these include; sweepnet, Pitfall and visual inspection.
RESEARCH PROGRESS
Survey work started in July and is on going in the study districts of Lira and
Palisa, where the cotton growing season commenced. The survey in Kasese will start in Mid September when their growing season commences. In Lira, the sub counties of Amach & Pala and Palisa town council & Kamuge sub county in
Palisa were selected and from each of the sub counties eight farmers where identified and their fields are being used for data collection. So far two samplings have been carried out in Lira and one in Palisa.
Samples of arthropods collected are currently being sorted out in the laboratory and preserved in a mixture of 250 ml of 4% aqueous formaldehyde solution and 50 ml detergent for further counting and curation. Key natural enemies found in and outside the cotton fields (in the surrounding fields) are also being sampled .
After the second sampling from Palisa (end of the vegetative stage sampling) data collected will be subjected to Analysis of Variance (ANOVA) and Student
Newman Keuls (SNK) test for separation of means.
The preliminary analyzed results of the vegetative stage study will be ready by mid September.
The Kasese survey as indicated above will commence in Mid September by mid
October the results obtained from the Vegetative stage will also be amalgamated
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with the Lira and Palisa results of the same stage and subsequently a general analysis of all the three regions will be done.
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