2000年三代三化螟在姜堰市大发生，大部分乡镇控制了为害，平均水稻白穗率在 1％上下。但白穗率 10％以上的田块并不少见，还出现了白穗率 50％以上的田块。为了总结三化螟大发生年容易防治失利，造成严重为害的原因，笔者等于 8月下旬至 10月初在全市范围内进行了实地调查，现 Three generations of three generations of rice borer occurred in Jiangyan in 2000, most of the towns and villages to control the damage, the average rice white spike rate of 1% up and down. However, the rate of white spike more than 10% of the plots is not uncommon, but also appeared white spike rate of more than 50% of the plots. In order to summarize the large annual occurrence of the three borer easy to prevent defeat, causing serious damage, the author is equal to the end of August to early October conducted a field survey within the city, and now