The pale yellow or green caterpillar is about 1 inch long when grown with a broad dusty stripe running down the back bordered on each side by a yellow stripe. It is also covered with tufts of long whitish hairs. There are can be two to four generations per year depending on climate. The final generation is typically in the fall and is the worst infestation. Fall webworms overwinter as pupae in silken cocoons under ground trash or on rough tree bark.
Moths emerge from the cocoons and lay eggs in hair-covered masses on the underside of leaves.
Entire branches can be covered in webs and in severe infestations, the entire tree can be covered with several webs. The caterpillars eat the tender portions of the leaf, leaving the large veins and mid-rib. In the event of severe defoliation, the tree may be weakened possibly die. These insects many tree species, but are most prevalent in mulberry, ash and pecan. Others trees including hackberry, peach, willow and red oak are vulnerable but severe infestation is not as common in our area.