Abstract :
The 3KGy dose caused complete mortality for Sitophilus zeamais adults 48h post-irradiation. The eggs of Sitotroga cerealella failed to hatch at both doses 1.5&3KGy. Usually the newly hatched larvae from irradiated eggs with 0.75 KGy died soon after hatching without passing through metamorphosis. Different concentrations (0.5, 1, 2, 4 and 8 %) from four selected oils of onion, clove, and orange were tested for their toxicity activity against eggs and weevils. Experiments conducted revealed that garlic oil at 4% concentration was more efficient against the adult weevil than the egg moth and exposure period 48h, which gave 100% and 76.66 % mortality, respectively. It was noticed that the same trend of toxicity for the three other oils held for both species. The reduction in the percent eggs hatched; pupation and emergence were directly proportional to the level of concentrations of tested oils and the time of exposure. Also, the reduction in the F1 progeny weevils was positively correlated with concentration and exposure time. It is possible using both favorite oils garlic and clove at LC95% to spraying polypropylene sacs for protection irradiated maize grains with a dose 3KGyfrom reinfestation by the tested insect within the storage period tested.
Keyword :
gamma radiation; Plant oils; stored maize; Sitotroga cerealella; Sitophilus zeamais