Bagworms

• Bagworm caterpillars are easily identified by the 1.5 to 2-inch long hanging sacs they build on the branches of evergreen trees and shrubs. Since the silk bags are covered with needles from the host tree, these structures may resemble young or striped pine cones. The sturdy bags camouflage the larvae when they hatch in early May, and the pests use the bag throughout their life cycle to mate and lay eggs early in fall. The insects prefer evergreens but may also attack some deciduous trees.
  
  

Western Tent Caterpillars

• Western tent caterpillars are bright orange larvae with black and blue markings. Though the larvae prefer deciduous trees, they occasionally attack broadleaf evergreen trees and shrubs. Adult moths lay egg masses on trees in June, which hatch the following spring and grow until early June. The caterpillars build white, silky tent-like structures to protect them from bad weather.
  
  

Sawfly Larvae

• Small, green sawfly larvae may be mistaken for tent caterpillars, as they also build silken nests in evergreen trees. Adult sawflies are beneficial pollinators, so small infestations of larvae should be left alone. Heavy populations, however, can result in severe defoliation.
  
  

Control Methods

• Hand-pick bagworm sacs in fall, winter or early spring and burn them in a controlled area away from the infested tree. Scrape tent caterpillar egg masses into a bucket of soapy water in fall, winter or early spring to prevent hatching. Remove any tent caterpillar tents you see and drop them into a bucket of soapy water. Kill any of the larvae in their early stages with an application of an insecticide containing carbaryl or bacillus thuringiensis.