The great basin tent-caterpillar is the most abundant form of Malacosoma found in the Rocky Mountain region of the United States. In Colorado, the species is often a serious pest of the aspen. It feeds upon a wide variety of deciduous trees and shrubs. In the foothills, Rhus trilobata and Prunus melanocarpa are frequently attacked. Whole aspen groves at higher altitudes are often defoliated by this species. In the mountains, the migrating larvae have occasionally been so numerous as to stop locomotives by greasing the rails with their crushed bodies.