一、主要农作物病、虫、杂草危害情况病、虫、杂草是农业生产的三大敌害。世界粮农组织对各国由于病、虫、杂草所造成的损失做了估计,每年农作物损失700—900亿美元,其中虫害占40%,病害占33%,杂草占27%。在各种农作物中,常年因病、虫、杂草危害,小麦减产35%、水稻46%、高粱和谷子38%,马铃薯40%、棉花60%、菸草62%、甘蔗55%、甜菜24%、花生40%、苹果30%、咖啡40%。美国病虫草害每年损失110亿美元,占总产值20—30%,苏联每年损失54亿卢布,占 First, the main crop diseases, insects, weeds Hazard Diseases, insects, weeds are the three predators of agricultural production. The World Food Program estimates the losses caused by diseases, insects and weeds in various countries. The annual loss of crops is 70-900 billion U.S. dollars, of which pests 40%, diseases 33% and weeds 27%. In all kinds of crops, perennial due to disease, pests and weeds, wheat yield reduction of 35%, 46% of rice, sorghum and millet 38%, potato 40%, cotton 60%, tobacco 62%, 55% sugar cane, sugar beet 24% , Peanut 40%, apple 30%, coffee 40%. Illicit pests and diseases in the United States lose 11 billion U.S. dollars each year, accounting for 20-30% of the total output value. The Soviet Union lost 5.4 billion rubles annually, accounting for