Survey on usage and effectiveness of chemicals for managing pod borer and aphids of yard long bean in bangladesh

Abstract

Abstract : The study was conducted in intensive yard long bean growing areas such as Jessore, Dhaka, Narsingdi, Comilla and Chittagong of Bangladesh to know the usage of effective chemicals in managing pod borer and aphids of yard long bean during March to October 2009 in the farmers’ field. Farmers are used to apply more chemicals to minimize the damage done by insect pests of yard long bean. Sometimes they are applied as high as 12-15 times in the growing season. Insecticides used in different combinations were non selective, however, having different level of toxicity both to the pests and the natural enemies. Proclaim 5 SG (Emamectin benzoate) performed better as a singly applied insecticide where infested pod yield was the lowest (0.78 t/ha). Net return (123930 tk/ ha) and BCR (1.36) were the lowest where malathion was applied singly. Spinosad performed better as a singly applied insecticide where net return (149090 tk/ha) and BCR (1.58) were the highest. Spinosad plus malathion performed better than carbosulfan plus dimethoate applied as a mixture where infested pod yield was the lowest (0.85 t/ha) and benefit Cost Ratio (BCR) was the highest (1.90).