Feasibility of protecting maize varieties with vegetable oils to save losses in storage due to Sitophilus oryzae Linn.

The effect of eight different vegetable oils, viz., mustard, soya bean, coconut, neem, groundnut, cotton seed, sesame and castor at five doses, viz., 0.40, 0.90, 1.40, 2.35, and 3.30 ml/kg of grain on seven-day old adults of Sitophilus oryzae Linn. infesting three maize varieties, viz., Pusa Arun, AEB comp. (white) and VL-42 was studied in storage. Irrespective of the oil used as grain protectant for different varieties, the highest per cent mortality of S. oryzae adults occurred one day after the treatment of the grains. Coconut and soya bean oils at 3.30 ml/kg grain were highly effective in protecting the grains of the various maize varieties, viz., Pusa Arun, AEB comp. (white) and VL-42. The average per cent increase in mortality of adult weevils due to application of the various vegetable oils as compared to the control was highest when the grains were protected with 3.30 ml/kg grain of coconut oil followed by soya bean and cotton seed oils. The average per cent increase in mortality of adult weevils, reduction in population, and avoidable loss due to damaged grains as a result of application of oils was highest in variety Pusa Arun, being 98.35, 53.81 and 38.42 respectively. The per cent avoidable loss due to damaged grains was highest in the case of grains treated with 3.30 ml/kg of grain of cotton seed oil followed by soya bean and coconut oils. The per cent reduction in the average population of S. oryzae was highest in the case of soya bean oil at 3.30 mUkg grain followed by cotton seed and coconut oils.