麦蚜与天敌相互关系研究及麦蚜防治指标初报

试验结果表明:小麦产量损失率与麦长管蚜、七星瓢虫幼虫关系极显著,与禾缢管蚜关系显著。经对田间麦蚜防治指标初步试验探讨,揭示了在麦蚜、天敌共存的农田系统内,由于天敌捕食控制作用,原来仅以麦蚜为害单因素所制定的防治指标可有较大幅度的放宽。

STUDY ON THE RELATIONSHIPS AMONG WHEAT APHIDS, NATURAL ENEMY AND YIELD LOSS OF WHEAT AND THE ACTION THRESHOLD OF APHIDS

The optimum regression design was used in field experiment to explore the relationships among English grain aphid Macrosiphum avenae(Fabricius) ,oat bird-cherry aphid Rhopalosiphnm padi (Linnaeus) ,Coccinella septeinpunctata Linnaeus and the yield loss rate of wheat,as well as the action threshold of wheat aphids in the coexistent system of aphids, natural enemies and wheat. The results showed that the yield loss rate increased closely with the density of M. avenue, and the effect of that of R. padi was minor,and the density increase in certain range of C. septempunctata was capable to reduce obviously the damage of aphids to wheat. It was indicated that as the natural enemies were relatively powerful in this coexistent system, the original action threshold of wheat aphids might be considerably relaxed owing to the good control effect of natural enemies.