Studies on the rice thrip (Thrips oryzae Williams) in the Tungtai area, Kiangsu Province.
Since the development of the double-crop system of rice cultivation and the extensive planting of early maturing varieties in China, Baliothrips biformis (Bagn.) (Thrips oryzae Williams) has become a more important pest of the crop. Studies in the Tungtai area of Kiangsu Province showed that there were about 10 generations of the thrips a year. The temperature threshold for development was about 11.5 deg C and the effective temperature summation was about 221.3 day-degrees. Adults of the overwintering generation emerged in mid-April; females subsequently oviposited on Leersia japonica and other grasses. During the first half of May, adults of the second generation moved to paddy fields, causing some leaf damage. Maximum damage was caused by the second to fourth generations during mid-May to mid-July (largest populations occurring in mid-June). Populations increased in size at the nursery or tillering stage of the plant but decreased rapidly at the elongation stage. A regression equation for predicting the best time for insecticide application is presented. Temephos (Abate) and carbaryl (Sevin) were the most effective of 6 materials evaluated for the control of nymphs and adults.