Efficacy of vegetable oils as grain protectant against Sitophilus oryzae (L.) in stored maize

The efficacy of seven vegetable oils viz., mustard, linseed, sesame, castor, soybean, coconut and groundnut @ 0.4, 0.8 and 1.2 ml/100 g grains of maize was tested as grain protectant against Sitophilus oryzae (Linn.) in laboratory during 2007–08 at Department of Entomology, Rajasthan College of Agriculture, Udaipur. Mustard oil @ 1.2% was found most effective causing highest adult mortality (75.00%) when released in freshly treated maize grains with, lowest grain damage (4.53%), weight loss (1.50%) and adult emergence (48.33 adults). High adult mortality and low grain damage, weight loss and adult emergence were observed at the beginning but mortality gradually declined and grain damage, weight loss and adult emergence increased as the duration of treatment increased from fresh to 21 days. Groundnut oil @ 0.4% was found least effective. The germination was not adversely affected due to the treatments up to 120 days.