农田杂草种类多、繁殖力强、适应性广、抗逆性高,不仅与农作物争水、争肥、争光,而且传播病虫害,严重影响作物的产量和品质。据联合国粮食与农业组织估计,世界农业受杂草危害,每年平均减产9.7％。我国由于杂草危害,水稻每年约减产1成;麦类每年约减产2—3成。依靠人工或机械除草费力、费工、效率低、效果差;应用化学除草可节省用工、减轻劳动强度、提高防治效果,是实现农业现代化的一项重要技术措施。世界除草剂发展的历史不长,从1942年发现和使用2.4—D以来,到现在还不到50年,发展速度超过了杀虫剂和杀菌剂。从品种看,先后商品化的除草剂品种达300多种,目前使用的有150余种;从产量看,60年代以前,国外除草剂只占农药总产量的10— Many kinds of farmland weeds, strong propagation, wide adaptability, high resistance, not only compete with crops, fight fertilizer, win glory, but also spread of pests and diseases, seriously affecting crop yield and quality. According to the UN’s Food and Agriculture Organization, the world’s agriculture is endangered by weeds, with an average annual reduction of 9.7%. In our country, due to the damage of weeds, the annual output of rice is reduced by 10%; wheat is cut by about 2-3% every year. Rely on artificial or mechanical weeding effort, labor, low efficiency, poor results; application of chemical weeding can save labor, reduce labor intensity and improve the control effect is an important technical measure to achieve agricultural modernization. The world herbicide has not developed for a long time. Since the discovery and use of 2.4-D in 1942, less than 50 years have passed since its birth and its rate of development has exceeded that of pesticides and bactericides. From the species perspective, there are more than 300 kinds of herbicides that have been commercialized and over 150 currently used. From the perspective of output, before the 1960s, foreign herbicides only accounted for 10-