药剂防治三化螟,要掌握好用药时机。打击三化螟群体的大多数,才能取得良好的防治效果。为此,要求做好测报工作。从1965年起,我们先后应用期距预测法于三化螟测报,都收到较好的效果。这种方法可作短期、中期或长期预测,简便易行;历史资料不全的地方,可以引用邻近地区的资料试行;可节省调查次数和计算时间,并可及早了解整代螟虫发生消长动态,以便对照水稻 Three chemical control of rice stem borer, to grasp the timing of medication. Striking the majority of the three borer population, in order to achieve good control effect. To this end, requires good reporting work. From 1965 onwards, we have applied long-term forecasting method in the rice stem borer measured, have received good results. This method can be used for short-term, medium-term or long-term forecasting and is simple and easy to use. Where incomplete historical data can be piloted in neighboring areas, the number of surveys and calculation time can be saved. Control rice