Abstract:This insect occurs throughout the regions where the hosts grow in Shensi Province, but outbreaks only occurs in certain parts of them. Young trees of Pinus tabulaeformis, P. armandi and P. massonixna are severly attacked. There is one generation per year in Shensi Province. Winter is spent as full-grown larvae in silken cocoons in the litter or below the surface of soil. Many soecies of natural enemies have been collected, of which 10 belong to bracoidae, ichneumonidae and trichogrammatidae. The parasitism of larvae and pupae is about 40 per cent. The results of experiments showed that fenitrothion, monocrotophos and parathion were very effective for the control of the larvae. The appication of ultra-low-volume technique in the control of this pest is recomerded.