怎样正确使用Ｂｔ类生物杀虫剂Ｂｔ类生物杀虫剂仅有胃毒作用，且附着力差．所以只有掌握正确使用方法，才能充分发挥其药效。如用以除治棉铃虫，则应针对其幼虫孵化后取食卵壳，二龄后在苞叶内蛀食幼蕾的习性，掌握住以下要点：一、适期用药棉铃虫一般由产卵到孵化需３～... How to correctly use Bt biological insecticide Bt biological insecticides only stomach poisoning effect, and poor adhesion. So only master the correct use of methods in order to give full play to its efficacy. If used in addition to the treatment of bollworm, it should be hatched eggs larvae after hatching, after the second age in the husk eaten young bud habits, to grasp the following points: First, the appropriate medication Bollworm generally spawning Need to hatch 3 ~ ...