Pest

Tent caterpillars and fall webworm

Malacosoma spp., Hyphantria cunea

Caterpillars that live in groups inside silk. Tent caterpillars build tents in branch forks in spring and go out to feed; fall webworm wraps its web over branch ends in late summer and feeds inside. Healthy trees usually leaf out again the next spring.

Signs

• Spring: a dense silk tent in a branch fork, with hairy caterpillars going out to feed.
• Late summer: loose, dirty webs over the ends of branches with caterpillars feeding inside.
• Shiny, dark egg bands circling twigs over winter (tent caterpillars).

What favors it

Tent caterpillars favor cherry, apple, crabapple and aspen; fall webworm walnut and many other trees.

Prevention

• Scrape off and destroy the dark egg bands on twigs over winter (tent caterpillars).
• Prune or pull out tents on cold or wet days, when the caterpillars are inside.

Crops it shows up on

Shade & ornamental trees; Apple, pear & stone fruit.

Often confused with

Sources

• Eastern Tent CaterpillarsUniversity of Maryland Extension
• Fall WebwormUniversity of Wisconsin-Madison Extension

Why →