EXTENT OF SUPPRESSION OF LEAF FOLDER, CNAPHALOCROCIS MEDINALIS,GUEN. POPULATION BY SOME SELECTED INSECTICIDES IN THE FIELD OFSCENTED LOCAL PADDY CULTIVAR TULAIPANJI AT RAIGANJ, UTTARDINAJPUR, WEST BENGAL, INDIA

Extent of suppression of paddy leaf folder population by seven selected insecticide formulations were carried out in the field of local paddy cultivar Tulaipanji during four consecutive autumn-crop seasons of 2007-2010 at Raiganj, Uttar Dinajpur, West Bengal, India. Experiment was laid out in randomized block design and had five replications for each year. All the treatments were effective significantly to suppress adult individuals/ trap (LFA), larval individuals/hill (LFL) and the incidence of damaged leaf (DL%). Least number of LFA, LFL and DL were noted in imidacloprid 17.8 SL (100ml/ha) treated field. This was followed by carbofuran 3G (30 kg/ha), fipronil 0.3G (750 ml/ha), monocrotophos 36 WSC (1125 ml/ha), propenphos 50 EC (500 ml/ha), clopyriphos 20EC (1875 ml/ha) and bifenthin 10 EC (500 ml/ha) in ascending order. Extent of suppression of adult individuals, larval population and the degree of damage was maximum in imidacloprid 17.8 SL treated plots (83.23% LFA, 85.45% LFL and 89.61% DL). This was followed by carbofuran 3G, fipronil 0.3G, monocrotophos 36 WSC, propenphos 50 EC and chlopyriphos 20 EC respectively in descending order. The minimum suppression efficacy was recorded in bifenthrin 10 EC treated plot (35.98% LFA, 35.98% LFL and 48.07% DL).