在使用杀虫剂和害虫斗争过程中 ,学者经常遇到一个十分令人头痛的问题 ,就是害虫会逐渐产生抗药性 ,使得许多原来很灵验的药物逐渐失却固有锋芒。有时甚至会出现相反的后果 ,就是所谓“再发猖獗”现象。原来在自然界里 ,每种害虫往往都有许多天敌伴随而生 ,它们在互相制约中维 Scholars often encounter a very troublesome problem in the fight against insecticides and pests, that is, pests gradually develop resistance, which gradually leads to the gradual loss of many pristine drugs. In some cases, the opposite effect may even occur. It is the so-called “recurrent rampancy.” Originally in nature, each pest often have many natural enemies accompanied by their mutual restraint in the dimension