Experts report a larger than normal bag worm and web worm infestation in North Texas this year.
Web worms are caterpillars that feed on tree foliage inside large webs that they spin in the tree for protection. Bag worms are caterpillars that make themselves a bag jacket that looks like a small Christmas ornament for protection as they feed on foliage in a tree.
Urban Entomologist Mike Merchant with the Texas A & M AgriLIFE Extension office in Dallas said he has received an unusual number of complaints from residents about bag worm infestation. He is not certain why bag worms seem more common this year.
He said weather conditions have provided healthy foliage that may explain an early infestation of web worms which are more prevalent on the fall.
Web worm infestation may increase as fall approaches.
Merchant said web worms can consume up to 20 percent of a tree's foliage without serious damage to the tree. But he still recommends removing with a rake those webs that can easily be reached and perhaps spraying a tree to kill the pests.
Merchant said a severe bag worm infestation can kill a tree.
This website offers information and links to more detailed AgriLIFE Extension publications on web worms and bag worms.
Also, here's a blog with more information: http://insectsinthecity.blogspot.com