森林病虫害,是森林灾害中除了森林火灾,乱砍滥伐外的一大灾害。在开展防治工作时,很多专家和科技工作者都强调用生物防治。因为这种防治方法可以保护天敌,利用天敌。那么什么是天敌呢?在自然界中,一种动物(甲)被另一种动物(乙)所捕食或寄生而致死亡时,则动物乙就是动物甲的天敌。如1989年8月底9月初对华宁县盘溪乡九甸小龙潭松毛虫危害情况的调查中,发现松毛虫茧80％以上被蚂蚁和其它虫吃空。此外,松毛虫还会被灰喜鹊捕食或被寄生蜂、寄生蝇寄生,蚂蚁、灰喜鹊、寄生蜂和寄生蝇便是松毛虫的天敌。害虫被天敌大量捕食或寄生致死,害虫就不可能猖獗,林木也就不会遭受严重灾害。 Forest pests and diseases, in addition to forest fires in forest disasters, deforestation and a major disaster. In carrying out prevention and control work, many experts and scientists emphasize the use of biological control. Because this method of prevention and control can protect natural enemies, the use of natural enemies. So what is a natural enemy? In nature, when an animal (A) is predatory or parasitic by another animal (B) and dies, Animal B is the predator of Animal A. For example, at the end of August 1989 and early September 1989, we investigated the damage of pine caterpillars in Jiudian Xiaodongtan, Panxi Township, Huaning County and found that over 80% of the cocoon of pine caterpillars were eaten by ants and other insects. In addition, the pine caterpillars will also be gray magpie prey or be parasitic wasps, parasitic fly parasites, ants, ash magpies, parasitic wasps and parasitic flies are the natural enemies of pine caterpillars. Pests are predators or parasites lethal by natural enemies, pests can not be rampant, and forests will not suffer serious disasters.