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最近几年美国的生物防治有了很大的增长,生物制剂的生产也随之有了很大的增加。主要的生物制剂是苏云金杆菌(Bacillus thuringiensis——турицид;дилел等),某些生物制剂最近八年增加了20倍。美国的生物制剂防治面积每年达100万公顷以上,其中包括蔬菜和20%烟草种植园内的夜蛾——Heliothis。1971年这些生物制剂的销售量达500万美元,播种或植苗的造林成本费每公顷为3.5—15美元。与化学保护的成本费几乎相等。
In recent years, there has been a great increase in the biological control in the United States, and the production of biologics has also greatly increased. The main biological agent is Bacillus thuringiensis (тирицид; дилел, etc.), some of which have increased 20-fold in the last eight years. The United States has more than 1 million hectares of biocontrol crops each year, including vegetables and Heliothis, a 20% tobacco plantation. In 1971 sales of these biologics amounted to $ 5 million, and afforestation costs for sowing or planting seedlings were $ 3.5 to $ 15 per hectare. And chemical protection costs almost equal cost.