There are a couple of natural ways to get rid of canker worms.
For one, you can use a bacteria-based pesticide. These pesticides only affect certain insects (like canker worms) and won’t hurt other, beneficial insects (such as bees). This kind of targeted attack can be tricky. You have to apply this pesticide early in their life cycle. This is usually before we see them hanging down, on their silk, from the tree.
A another natural way to get rid of canker worms is through predators. There are several creatures that eat canker worms. Some birds, insects and even rodents will eat them. The problem is the canker worms strategy to survive is through their large numbers. There are so many canker worms that predators can’t possibly eat them all.
Another natural approach to canker worms is to let them do their thing, but take care of the tree. While most trees will be able to replace their leaves, after the canker worms go to town on them, this is much easier when the tree is healthy. Make sure your trees have plenty of water and nutrients, and they can bounce-back quickly.
Of course, the best way of getting rid of canker worms is to prevent them from infesting a tree, in the first place. This is why people use tree bands. Banding a tree prevents the adult form of the canker worm from crawling up the tree and laying its eggs.