The signs of fall are all around us: shorter days, cooler temperatures, pumpkin-spiced foods and an abundance of silky nests in hardwood trees and shrubs.
That last sign is the often-unwelcomed indication that the fall webworm has arrived. The silky nests you see in wild cherry and fruit trees and some maples are the product of fall webworm larvae, which emerge in late summer and early autumn. The webs protect the larvae as they feast on the leaves. As they move on to new areas of the tree to eat, their nests grow larger. MORE
SOURCE: https://extension.unh.edu/blog/how-deal-fall-webworms