The effect of some rice varieties on the biology of the stalk-eyed fly Diopsis thoracica West was investigated. The rice varieties affected the developmental period from egg laying to adult emergence, the sex ratio, percentage survival, adult weights on emergence, ovary development and the rate of tiller damage by a single larva. The rice varieties OS6 and Tos 4121 were consistently the most unfavourable in terms of insect growth; but were the most susceptible in terms of damage. Thus varietal susceptibility to damage by the insect seemed to be different from varietal suitability for its growth.
