雪毒蛾Stilpnotia salicis(Linnaeus)分布于河北、山西、内蒙古、河南、宁夏、青海、黑龙江、山东、辽宁、江苏等省区,是三北防护林地区杨树的主要害虫。近年来此虫猖獗成灾,大发生时可将树叶全部食光,严重地影响了杨树的生长。在坝上地区,雪毒蛾每年发生一代,老熟幼虫6月下旬进入化蛹盛期并随即羽化交尾产卵。幼虫7月下旬开始孵化,取食到9月中旬,当气温下降时,在树皮缝和树干伤疤处群居越冬。1981年夏,在康保县大青沟林场的杨树林内,发现不同龄期的雪毒蛾幼虫自然罹病死亡。幼虫感病后,早期症状不明显,稍后表现取食减少,行动和反应迟钝,死亡时往往用腹足或尾足钩住树干或树枝,成倒“V”形或倒挂下垂于树枝上。典型的病毒死亡虫尸体壁易 Stilpnotia salicis (Linnaeus) distributed in Hebei, Shanxi, Inner Mongolia, Henan, Ningxia, Qinghai, Heilongjiang, Shandong, Liaoning, Jiangsu and other provinces and autonomous regions, is the three North Shelterbelt poplar pests. In recent years, the worm has become rampant. When the outbreak occurs, all the leaves can be eaten, seriously affecting the growth of poplar trees. In Bashang area, the generation of snow moth each generation, mature larvae in late June into pupae and then eclosion spawning. The larvae hatch in late July and feed until mid-September when the temperature drops, wintering in bark joints and tree trunk scars. In the summer of 1981, in the poplar grove of Daqinggou Forest Farm in Kangbaoxian County, it was found that the larvae of natural larvae died of natural disasters at different ages. Early symptoms of larvae are not obvious, and later showed reduced feeding, action and unresponsiveness, death often with gastropods or tail feet hooked tree trunks or branches, into inverted “V” shape or hanging down on the branches. A typical virus death caterpillar body wall easy