Cankerworms are a yearly spring time visitor here in Charlotte. They bring with them tree damage and a mess. There are 3 different ways we can help prevent them from damaging your tree or making a mess of your property.
Tree banding is the most common method of cankerworm prevention/reduction. It’s a pretty low tech solution, consisting of putting a band around the trunk of the tree and applying a sticky substance around the band. As the females crawl up out of the ground towards the canopy of the tree they get stuck in the band and their journey ends. Banding is a pretty effective way to keep cankerworms in check but doesn’t usually keep all of them out of the tree. Banding needs to be done each year in the late fall/early winter and bands should be removed in the spring.
Treating smaller trees in the spring once the cankerworm has emerged and begun to feed is another method of control. The treatment consists of an insecticide sprayed in the canopy of the tree which deals with the cankerworms. This method is limited by the height of the tree and is best suited for smaller landscape trees such as Japanese maples, dogwoods or cherries. Spraying would need to take place each year and should last for the duration of the infestation during the spring.
The last option can work for both large and small trees and involves applying a product directly to the soil early in the spring that the tree then takes up through its vascular system. The product is moved to the leaves and the cankerworms ingest it when the begin feeding. This option should also be done each spring and is one that you should get prepared for during the winter to make sure it’s done in time.
Generally a single year of cankerworm feeding or even an entire defoliation will kill an otherwise healthy tree. Trees that have had significant damage will generally benefit from fertilization to provide nutrients back to the soil.