Analysis of Population Dynamics of Aphis glycines and Its' Natural Enemies in Northeast China

[Objective] Definite the population dynamics of soybean aphids,winged aphids and their natural enemies in northeast China.[Method]By using chessboard pattern sampling method,field systematic investigation was conducted on the population of soybean aphids and natural enemies. [Result]Soybean aphids occur in the field in the second ten days of June,and disappear in the second ten days of September.There are three growth peaks during its occurrence period. They're in the third ten days of June,the first ten days of July and August. Winged aphids occur in the second ten days of June and begin migrating to their winter hosts in the second ten days of August. They completely disappear between the end of August and the beginning of September. There are three growth peaks during occurrence period of winged aphids. They're at the end of June,from the end of July to the beginning of August,and the second ten days of August. Natural enemies occur early in the field and have an obvious followed phenomenon. [Conclusion] There are three growth peaks for both soybean aphids and winged aphids in the soybean field. And the natural enemies can control soybean aphids to some degree.