一、多年预测的意义和可行性 建国30多年,农业生态系统发生很大变化,导致病虫主要危害种类更替、猖獗区域变迁。这些规律不少已渐渐被了解,并得以预测;但又时时出现很多出乎意料的新问题。南方稻区在60年代中期以前,三化螟属常发性主要害虫;70年代,稻飞虱、稻纵卷 First, the significance and feasibility of years of prediction More than 30 years after the founding of the PRC, great changes have taken place in agro-ecosystems, leading to the replacement of major pests and diseases and the rampant regional changes. Many of these laws have gradually been understood and predicted; however, many unexpected new problems have emerged from time to time. Southern rice borer in the mid 1960s, the three borer is a common main pests; 70 years, planthopper, rice vertical roll