Effectiveness of conservation biological control against the cotton aphid Aphis gossypii Glover in okra fields: Evaluation in farmer’s fields

Effectiveness of conservation biological control against the cotton aphid Aphis gossypii Glover was evaluated in okra Abelmoschus esculentus（L.） Moench. fields at Ibusuki, Kagoshima from May to September in 2014. In a field where broad-spectrum insecticides had been applied frequently, natural enemies did not occur and A. gossypii populations increased rapidly in September. On the other hand, in a field where indigenous natural enemies were conserved and enhanced with selective insecticides and insectary plants （barley and sorghum）, natural enemies such as aphid parasitoids, ladybird beetles, hoverflies, predatory gall midges, lacewings, and flower bug, occurred and cotton aphids remained at low density, indicating that conservation biological control can be effective against A. gossypii on okra.