松毛虫是松树、落叶松的毁灭性食叶害虫,在国内很多省份连年猖獗成灾.最近北京西山林场创造了一种防治的新方法——塑料布环法,可以阻止越冬松毛虫幼虫上树为害.方法:越冬松毛虫幼虫上树前,在树干中部或下部绑一圈塑料布,布宽5～6厘米,接头处用大头针扭住,使布环不脱落即可.原理:北方地区的松毛虫多数以4～5龄幼虫在地面枯枝落叶层下越冬,当日 Pine caterpillars are devastating leaf-eating pests of pine trees and larches, which have been rampant in many provinces in China. Recently, a new method of prevention and control was developed by Xishan Forest Farm in Beijing - plastic cloth ring method, which can prevent wintering moth larva on the tree Damage.Methods: The winter pine caterpillar larva on the tree, in the middle or lower trunk tied a circle of plastic sheeting, cloth width 5 ~ 6 cm, twist the pin at the connector, so that cloth ring does not fall off. Principle: the northern region Dendrolimus most 4 to 5 instar larvae wintering in the ground litter layer, the same day