落叶松鞘蛾为害落叶松的针叶,是本地区的一大虫害。虫害大面积发生时,整个林分呈火烧状。主要发生在人工落叶松纯林和天然落叶松中龄纯林中。天然林一般发生在郁闭度0.3～0.5之间的背风向阳稀疏林分,林缘附近为害较重。鞘蛾为害过的林分当年,虽恢复,但影响了树木的生长,降低了球果的结实量。一、形态特征。成虫体长3毫米,雌蛾翅展8～9毫米,雄蛾翅展约6毫米。体翅暗灰色,翅细长,被银灰色鳞 Larch sheath moth damage larch needles, is a major pest in the area. When a large area of ​​pests occurred, the entire forest was burned. Mainly occurs in artificial pure larch forest and natural larch aged pure forest. Natural forests generally occur in sunny leeward sparse stand with 0.3 ~ 0.5 degrees of canopy closure. At that time, the forest moth damaged the sheath moth, although it recovered, it affected the growth of trees and reduced the fruit yield of cones. First, the morphological characteristics. Adult body length 3 mm, female moth wingspan 8 to 9 mm, male moth wingspan about 6 mm. Body wings dark gray, wings slender, silver-gray scales