Title: Effects of droughts on damage caused by cabbage root fly larvae

Final project
Year of publication:
Supervisors: Gudmundur Halldorsson
drought, climate change, insect pest, horticulture, Ghana


The goal of this study was to observe the potential effects of drought on the damage caused by insect pests in horticulture in Ghana, using cauliflower Brassica oleracea (L.) as a model plant, and cabbage root fly Delia radicum (L.) as a model insect pest. The study provided information on potential interactions between droughts and insect pests in cauliflower production. The experiment consisted of four treatments and four blocks organised as a full factorial design of: +/- drought and +/- pesticide treatment. The plants were planted on June 26 and harvested on August 2. During the experiment the longest leaf length was measured, the condition of plants was assessed and egg laying of cabbage root flies was monitored. After harvesting, damage on roots was assessed, the number of larvae and pupae recorded and biomass of plants measured. R software was used to test the effects of the different treatments on the variables that were measured. Pesticide treated plots had significantly higher aboveground and belowground biomass than non-treated plots. The treatments had a significant effect on the number of larvae on plant roots; the lowest number of larvae was found on plants treated with pesticide and the highest on plants not treated with insecticide and subjected to drought. The implications of these findings on horticulture in Ghana under future climate conditions are discussed.

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