Eastern tent caterpillar, Michigan trees, shrubs

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Eastern tent caterpillar - Malicosoma americanum

Favored host plants: Apple, crabapple, hawthorn, cherry, mountain-ash, cotoneaster and other members of the rose family. Eastern tent caterpillars overwinter in egg masses on twigs of the host plant.

Larvae normally hatch at about the same time that the host plant is beginning to leaf out. Look for young larvae around the time that Norway maple or Amelanchier are in bloom.

Management: Remove egg masses, or prune out webs while they are still small. Removing webs should be done on a cloudy or rainy day, when caterpillars are inside the web. If insecticide treatments are used, the web should be broken open, as the tents provide protection from some insecticide applications.

Mature larva of the eastern tent caterpillar.


Larvae create silken tents in the branch crotches and emerge from the tent to feed.	As larvae mature, they leave the host plant and look for a place to make their cocoons. The adults emerge in late June or early July.	Egg masses can be found encircling twigs throughout the winter and early spring. This is an older egg mass where larvae have already hatched. The egg masses should be removed before young larvae hatch.

Additional information

MSU Diagnostic Services for assistance in pest identification.
MSU Landscape Alert newsletters for information about the current growing season, pest concerns and plant advice.

This information was developed from A Pocket IPM Scouting Guide for Woody Landscape Plants by Diane Brown-Rytlewski. Purchase this in a pocket-sized guide for reference in the orchard from MSU Extension (publication E-2839).

The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the Michigan Agricultural Experiment Station, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.
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Updated 10/08/07