我场油松毛虫,为害较重。严重者树叶被吃光,受害后的2～3年间,树高生长下降80—90％,直径生长下降35～42％。1978年以来,我场开始利用树干围挂塑料帽的方法防治松毛虫,收到了较好的效果。但塑料布的利用率仅有50％左右;塑料帽围挂后易下垂与树干相贴,起不到阻止幼虫上树的作用;加工塑料帽需用剪子剪或用特制管刀压 My field of pine caterpillars, damage heavier. In severe cases, the leaves are eaten, after 2 to 3 years of victimization, tree growth is reduced by 80-90% and diameter growth is reduced by 35-42%. Since 1978, my field began to use plastic trunks around the trunk to prevent and cure pine caterpillars, and received good results. However, the utilization rate of plastic cloth is only about 50%. Plastic caps are easy to sag and stick to the trunk after hanging, which can not prevent the larvae from playing the role of the tree. The processing of plastic caps requires scissors or special knife pressure