Webworms: How They Can Affect Your Trees

by Russell Peters

The female moth actually lays the eggs on the underside of the leaf in early May after the tree leafs out.  The larvae hatch and build a web for protection, then begin to consume the foliage.  The webs expand as the worms increase their intake of foliage.  The feeding lasts about 2-3 weeks until they leave the tree and pupate.  The female emerges and the cycle can repeat 5 times a year requiring a different spray each time.  They do not move from tree to tree, as they only feed in the tree that the worms hatch from.  They generally cause no permanent damage, but we treat often because the client considers it a nuisance.