农田杂草是农业生产的一大危害。据联合国粮农组织估计。全世界每年因杂草、病虫害造成的损失达204亿美元。其中病害占27％,虫害占28％,线虫占3％,杂草占42％。我国15亿亩耕地中每年遭受草害的面积在3亿亩以上,由于草害而减产粮食150亿斤。人们为了克服和减轻杂草带来的巨大损失,采取各种措施来消灭杂草,化学防除 Farmland weeds are a major hazard to agricultural production. According to the UN Food and Agriculture Organization estimates. The world each year due to weeds, pests and diseases caused losses of 20.4 billion US dollars. Among them, diseases accounted for 27%, pests 28%, nematodes 3%, weeds 42%. Of the 15 billion mu of cultivated land in our country, the area suffering from grass weeds is more than 300 million mu each year, and the output of grain is reduced by 15 billion kilograms due to grass weeds. People in order to overcome and reduce the huge loss of weeds, take various measures to eliminate weeds, chemical control