Management of Thrips (Thysanoptera: Thr ipidae) on French Beans (Fabaceae) ir Kenya: Economics of Insecticide Applications

Abstract

TIlls study was conducted to measure economic benefit of using different spray schedules to control thrips on French beans. It was done using different spray regime scenarios of two insecticides: Lambda cyhalothrin (Karate 1.75% EC) and Methiocarb (Mesurol 500 SC). It is shown that increasing the number of sprays results to lower thrips infestations, explaining why local farmers practice calendar spraying. However, this lowers the net returns obtained from French bean sales. In contrast, application of one to two sprays maintains thrips below economic damage and provides the highest net returns. It is suggested that farmers should only use the effective insecticide after noting a density of three thrips per flower. TIlls is possible if farmers embrace monitoring of thrips buildup on French beans.