Field efficacy of genetically modified FK 95 Bollgard II cotton for control of bollworms, Lepidoptera, in Ghana

Abstract

Background: Cotton (Gossypium hirsutum L.) cultivation in Ghana is constrained by bollworms that damage squares (flower buds) and developing bolls, resulting in loss in seed cotton yield. Control of these insects is heavily dependent on insecticides that are costly and also pose health and environmental risks to users. Potential alternative control strategies have focused on using cotton genetically modified with the soil-borne bacterium Bacillus thuringiensis Berliner (Bt) that confer resistance against these pests. This study evaluated the field efficacy of the genetically modified FK 95 Bollgard II (FK 95 BG II) cotton for control of bollworms in Ghana. Results: Results showed that bollworm densities in the FK 95 BG II cotton were lower compared with those in the FK 37 conventional cotton. However, populations of the natural enemies, ladybird beetles Coccinella undecimpunctata L and lacewings Chrysoperla carnea [Stephens] were higher in the Bt compared with the conventional technology of pest management. On average, seed cotton yields were higher in the FK 95 BG II compared to those in the FK 37. Net profit and cost-benefit ratios also were higher for the Bt technology compared with the conventional practice, indicating that farmers would benefit more if they adopt the Bt technology of cotton pest management. Conclusion: The Bt cotton technology of pest management was more effective and economical than the conventional practice of wholly relying on insecticides and was a better management option for bollworm in cotton in the savanna ecology of Ghana.