Bio-efficacy of newer insecticides against rice leaf folder (Cnaphalocrocis medinalis Guenee) in Varanasi region

Abstract

Field trials were conducted during kharif season, 2016-17 with rice variety HUBR 10-9 to determine the bioefficacy of certain newer insecticides against rice leaf folder, Cnaphalocrocis medinalis Guenee. Results revealed that among all the insecticides after first spraying Thiocyclam Hydrogen oxalate (4%G) @500g a.i. per ha was found to be the most effective in both the sprays with a maximum reduction as 8.33 percent damage by insects per 10 hills and pymetrozine 150g a.i. per ha. was minimum reduction as 10.08 percent damage by insects per 10 hills. The mean per cent incidence in untreated control (13.57/ 10 hills) while after second spraying thiocyclam hydrogen oxalate (4%G) @ 500g a.i. per ha. One with a maximum reduction in mean per cent incidence of Cnaphalocrocis medinalis (5.25/10 hills), and pymetrozine 150g a.i. per ha. was minimum reduction as 9.60 percent damage by insects per 10 hills. The mean per cent incidence in untreated control was 17.48 / 10 hills. Thiocyclam hydrogen oxalate was observed to be best and the plots treated which realized a yield of 7.69 tonn/ha, but the yield in kg per plot obtained from cratap hydrochloride (7.19 tonn/ha), pymetrozine (6.69 tonn/ha) dinotefuron (6.24 tonn/ha) and, were statistically on par.