引起害虫患病的病原微生物,主要有细菌、真菌和病毒等。这些病原微生物,在适宜的生态环境条件下,往往使害虫形成流行病,导致害虫大量死亡。例如,1981年承德地区林业局靳家沟试验林场的松林内,松毛虫自然发病死亡率高达50—80％,发病范围波及到20余华里。由此可见,调查、发现、识别、分离、利用病原微生物,对防治林木害虫有一定现实意义。 Pathogenic microorganisms that cause pests, mainly bacteria, fungi and viruses. These pathogenic microorganisms often cause pests to become epidemic under suitable ecological conditions, resulting in a large number of pests death. For example, in 1981, Chengde Forestry Bureau Jinjiagou experimental forest farm pine forest, the natural mortality of Moth caterpillar as high as 50-80%, the incidence spread to more than 20 Huarui. Thus, the investigation, discovery, identification, separation, use of pathogenic microorganisms, prevention and control of forest pests have some practical significance.