Effects of cheaply available grain diets on development, adult emergence and sex ratio of rice moth, Corcyra cephalonica (Stainton)

Abstract

The milled grains of sorghum (Sorghum bicolar L. Moench), maize (Zea mays L.), bajra (Pennisetum typhyoides L.), alone and in different proportions were mixed to prepared eight diet to rear and maintain the rice moth, Corcyra cephalonica. The milled grains were sterilized at 110oC and all the diets were fortified with 0.1 percent formalin, 2.5 percent w/w yeast powder and streptomycin sulphate @ 0.5 g/3 kg of media grains. The study revealed that among all grains and their combination, evaluated, sorghum proved to be significantly better with shortest average development period of 62.13+0.98 days, with range of 30-141 days and longest (92.25±2.39) on the ‘Bajra’ days with range of 40-150 days which was at par with ‘Bajra’ + maize (2:1), (89.22±1.06) days. The sex ratio (males to females) was highest in sorghum (1:1.42) and lowest of (1:1.03) in case of sorghum + ‘Bajra’ (2:1). Adult emergence was highest from the sorghum grains 87.77 percent and lowest from the ‘Bajra’ grains 39.00 percent. The adult emergence from sorghum + maize (1:1), 82.47 percent was significantly higher than the maize + sorghum (2:1), 76.17 percent but was significantly lower than the sorghum + maize (2:1) 85.00 percent.