Evaluation of Effective Period of Seed Treatment Insecticides against Cotton Jassids [amrasca Biguttula Biguttula (ishida)]

The present study was conducted during Kharif, 2010-11 at the Experimental Farm of Cotton Improvement Project, Mahatma Phule Krishi Vidyapeeth, Rahuri to test the efficacy of imidacloprid 600 FS, thiamethoxam 350 FS and carbosulfan 25 DS as seed dressing insecticides against cotton jassid, Amrasca biguttula biguttula (Ishida). The results revealed that carbosulfan 25 DS @ 50 g kg-1 seed was found to be effective in checking jassid population upto 42 DAE. The next promising treatment was carbosulfan 25 DS @ 40 g kg-1 of seed, thiamethoxam 350 FS @ 4 ml kg-1of seed. However, it was with thiamethoxam 350 FS @ 4 ml kg-1of seed and phorate 10G @ 1 kg a.i. per hectare. Both seed treatment of carbosulfan, thiamethoxam and phorate proved most effective than imidacloprid in protecting the crop from jassids below economic threshold level in early growth period. These treatments appeared to be the most economical and recorded maximum seed cotton yield. Imidacloprid was observed to be less effective than carbosulfan and thiamethoxam and phorate against cotton jassids, might be due to continuous selection pressure of imidacloprid ultimately resulted into development of resistance in jassids