本文主要研究白背飞虱,褐稻虱两个种群在早稻上的消长动态。由于白背飞虱迁入与主迁入均比褐稻虱早,迁入虫量大,从而构成在早稻上白背飞虱发生为害的主要种群。由于褐稻虱主迁入迟,而且种群密度制约影响较小,加上白背飞虱迁出期早,造成7月中下旬褐稻虱虫口密度上升的趋势。 This paper mainly studies the growth and decline of two populations of whitebacked planthopper and brown planthopper on early rice. As the white-backed planthopper migrated in and moved in earlier than the brown planthopper, the number of migrating pests was large, which led to the main population of white-backed planthopper occurring in early rice. Because of the late migration of brown planthopper and the less influence of population density control, and the early departure of WBPH, the density of brown planthopper population increased in the middle and late July.