Canker worms are babies, but they’re not cute. They are the larval form of a moth. When the weather starts to get colder, these moths emerge from the dirt beneath a tree to breed. After breeding the females (who are wingless) crawl up the tree, in order to lay its eggs. These eggs hatch in the spring and become the canker worms we all hate.
After the canker worms dangle down from their silk, sometimes getting caught in our hair and clothes, they burrow away and form a cocoon to become the next generation of moths in the fall.
This is why we need to band our trees in the fall.