Mike’s Gardening Blog: What To Do About Fall Webworms
Looking across the street the other day I saw in the trees fall webworms. Those white fuzzy worms feeding away on the fruitless mulberry tree. The white webbing was encasing hundreds of worms. The fall webworm is a native pest of shade trees and shrubs and appears from late summer through early fall. It feeds on many species of deciduous trees. Fall webworms construct its nest over the end of the branch. The large conspicuous webs contain caterpillars, dead partially eaten leaves, and fecal droppings.
My neighbor and I discussed the options on removing webworms. One action he could take was to cut out the web full of worms. Another option is to use a chemical sprayer that connects to the water hose with a product that contains BT (Bacillus Thuringensis) or Spinosad (Fertilome Bore, Bagworm, Tent Caterpillar & Leafminer Spray).
Yet another option is to use Systemic Drench applied around the base of the tree. This is a slower way to kill the webworms. A drench will take time to enter the root system of the tree and be carried up to the branches where the worms are feeding. A drench is best done early in the spring before you see the worms.