Archive:Poplar/Fall Webworm

From Bugwoodwiki

From: Ostry, Michael E.; Wilson, Louis F.; McNabb, Harold S., Jr.; Moore, Lincoln M. 1988. A guide to insect, disease, and animal pests of poplars. Agric. Handb. 677. Washington, DC: U.S. Department of Agriculture. 118 p.

Importance The larvae of this web marker feed on more than 100 species of trees but moderately prefer Populus. Trees of all sizes may become covered with webs. Although spectacular because of its heavy webbing, the insect has little effect on the tree because the foliage is lost near the end of the season.

Look For:

• Large webs (up to 3 feet long) spun over the foliage in late summer, sometimes covering entire trees.

• Hairy larvae with yellow and black bodies in the web.

Larval cluster of fall webworm.

Biology

There may be from one generations in the North to four generations in the South. The female moths lay eggs in clusters on the undersides of leaves. Larvae feed in clusters and spin the characteristic web around the foliage to protect themselves. They pupate in bark crevices. Overwintering is in the pupal stage.

Monitoring

Check trees in summer for webs. Consider control only if branches die.

Control

Control generally not recommended. When there are a few webs, they can be cut and burned. If control is necessary, apply Bt (Bacillus thuringiensis) or a recommended chemical insecticide before larvae form webs.

Larval cluster of fall webworms.