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The City of Portland, Oregon

Portland Trees

Call before you cut

phone: (503) 823-TREE (8733)

email: trees@portlandoregon.gov

1900 SW 4th Avenue, Portland, OR 97201

Web Worm and Tent Caterpillar

Description

Several species of caterpillar create a web or tent in the branches of trees and feed on the tree’s foliage. The caterpillars rarely cause severe damage to trees unless stressed trees are subject to repeated spring defoliation.  

Susceptible species

Fruit trees, cottonwoods, aspen, ash, and various other species.

Treatment

Web worm and tent caterpillar can by controlled mechanically by pruning out infected areas or chemically by insecticide treatment on young colonies. However, pruning can often cause more damage to the tree than the web worm or tent caterpillar.