The relationship between the seedling date and population densities of small brown planthopper and incidence of rice stripe leaf blight in single japonica rice
It will be an effective "green prevention" measure of reducing the occurrence degree of rice stripe leaf blight by keeping away the seedling stage of the single japonica rice from infection peak period of small brown planthopper.The effects of the seedling date of the single japonica rice on population densities of small brown planthopper and the incidence of rice stripe leaf blight were studied at different sowing dates.The results are as follows.With the delay of seedling time from mid-May or late May to early-June or mid-June,the popula-tion densities of small brown planthopper declined obviously,and the beginning and peak period of rice stripe leaf blight disease was significantly delayed;the number of peak incidence was reduced;the incidence was decreased significantly,and the rice panicles and yield increased.Given the migration peak of the first generation of small brown planthopper adult and rice full panicle stage,the seedling date of single japonica rice should be postponed until June 9-14 in serious area of rice stripe leaf blight disease occured in southern Jianghuai.