According to the environmental protection agency in 1999 growers in states using high amounts of bt cotton sprayed 21 percent less insecticide than usual on the crop . that ' s a dramatic and impressive reduction says stephen johnson an administrator in the epa ' s office of pesticide programs 根据美国环保署的资料， 1999年大量种植bt棉花的各州，杀虫剂的喷洒量比往常减少了21 % .环保署病虫害防治部门的行政人员强森说，那个数字“非常戏剧性，让人印象深刻” 。
