THE BIOLOGY AND CONTROL OF SOME COMMON LEPIDOPTERAN PESTS OF VIRGINIA TOBACCO

MD. JUSOH MAMAT and LIM GUAN SOON

SUMMARY

The biology of the three common lepidopteran pests of tobacco; Chloridia assulta, Spodoptera litura, and Psara submarginalis were studred. and found to have a life cycle of 16-29, 13-32, and 21-35 days respectively. Among these species, S. litura was noted to be most productive with a high net reproductive rate of 318.1 as compared to C. assulta and P. submarglnalis (38.0 and 49.0 respectively). The studies also showed that there was about 40-50% real mortalitv for all the three species under laboratory rearing conditions. Their survivorship curves were of the convex type where a higher mortality occurs towards the end of the life span. About 60% of the population apparently succumbed to old age while, 40% to egg, larval, and pupal mortality. Among the eight insecticides evaluated in the field on tobacco as foliar sprays/drench, it was found that not all the test chemicals were equally effective against the three lepidopteran species. In general, permethrin, metamidophos, decamethrin, and monocrotophos were more effective as compared to triazophos, Mega BT + Nu-Film-17, carbaryl, and fenvalerate all of which were significantly better than the untreated controls.

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