Natural adjustment of population density of Larch casebearer (Coleophora dahurica)

Abstract

Population increase of Larch casebcarer (C. dahurica) were controlled by comprehensive factors. Spring wind caused 27% of larvae on crown to fall down. Early and late frosts, larch caterpillar, sawfly and needle cast of larch could reduce the food quality and quantity of larch casebcarer and had indirect effects on population density. Birds, ants and spites were the main predators ofC. dahurica. The parasite complex comprisedPtermalidae, Eulophidae, Ichneumonidae andBraconidae. “Self-adjustment”, of population caused by “self-population density”, only runs effectively at a high larval density.