因受大范围的气候异常和国外虫源等因素的影响,1991年水稻稻飞虱在南方大部分稻区和部分北方稻区大发生,发生范围和发生危害程度接近或超过历史最重的1987年, 北方稻区褐飞虱暴发为害是史无前例的。据初步统计,全国稻飞虱全年发生3.14亿亩, Due to a wide range of climatic anomalies and foreign insect sources and other factors, in 1991, rice planthoppers occurred in most of the southern rice area and part of the northern rice area, the occurrence and extent of damage close to or exceed the history of 1987. In 1999, the outbreak of brown planthopper in the northern rice area was unprecedented. According to preliminary statistics, 314 million mu of planthopper occurred throughout the year in the country,