EFFECT OF BACILLUS THURINGIENSIS BERLINER FORMULATION AGAINST THE RICE LEAF FOLDER CNAPHALOCROCIS MEDINALIS GUENEE (PYRALIDAE: LEPIDOPTERA)

ABSTRACT Two field trials were conducted to evaluate the bioefficacy of Bacillus thuringiensis Berliner, water soluble granular formulation against the rice leaffolder, Cnaphalocrocis medinalis Guenee. The study revealed that the treatment containing B.t. formulation @ 2.5 kg/ha registered the lowest leaffolder damage of 8.21 per cent that was on par with monocrotophos 36 WSC @ 500 g ai/ha in 7 DAS during the first spraying. On 10 DAS of the first spraying all the treatments recorded more than 13.00 per cent damage, but the low leaffolder damage of 13.65 per cent was recorded in B.t. formulation @ 2.5 kg /ha. The highest leaf folder damage of 18.40 and 17.38 per cent was registered in B.t. formulation @1.0 kg/ha and untreated control, respectively. The B.t. formulation failed to check the leaffolder damage due to the outbreak of the pest induced by high temperature coupled with low relative humidity. The highest grain yield of 28. 58 kg/ plot was registered in B.t. formulation @ 2.5 kg/ha, followed by B.t. formulation @ 2.0 kg/ha.