I’m sure by now you have noticed trees containing unsightly, light-grey webs towards the ends of their branches. These webs contain the fall webworm, a yearly pest of several trees all across North America. Fall webworms feed on over 85 species of trees. Hickory, American elm, pecan, walnut, and various fruit trees are their preferred food species. Willow, persimmon, maple, sweetgum, cottonwood, and alder are also favored host trees.