稻纵卷叶螟之所以防治难,一个重要的原因就是防治适期难掌握。各地在防治中,都以2龄幼虫高峰期作为施药防治适期,而2龄幼虫高峰期一般是在螟蛾高峰日期加10 d来确定的。在田间调查过程中,作者发现应用这个方法存在大发生年防治适期明显滞后,小发生年由于蛾量少,高峰期不明显,难 The reason why the prevention and control of rice leafroller difficult, an important reason is that prevention is difficult to master the appropriate period. Around the second instar larvae were used as control periods during the period of control, while the second instar larvae were determined at the peak of the fescue moth by 10 days. In the process of field investigation, the authors found that there is a significant lag in the application of this method for the prevention and control of malaria in the large occurrence year, the small occurrence year due to less moths and less obvious peak periods,