Cankerworms – Definition & Detailed Explanation – Tree Diseases and Pests Glossary

I. What are Cankerworms?

Cankerworms are a type of caterpillar that belong to the family Geometridae. They are commonly found in North America and are known for their destructive feeding habits on trees. There are two species of cankerworms: spring cankerworms (Paleacrita vernata) and fall cankerworms (Alsophila pometaria). These caterpillars are small, measuring around 1 inch in length, and are typically green or brown in color.

II. How do Cankerworms damage trees?

Cankerworms damage trees by feeding on the leaves, buds, and young shoots. They have voracious appetites and can quickly defoliate a tree if left unchecked. This can weaken the tree, making it more susceptible to diseases and other pests. In severe cases, cankerworm infestations can lead to the death of the tree.

III. What are the signs of a Cankerworm infestation?

The signs of a cankerworm infestation include skeletonized leaves, defoliation, and the presence of caterpillars on the tree. Cankerworms are most active in the spring and fall, which is when they do the most damage to trees. It is important to monitor trees for signs of cankerworm infestations so that appropriate action can be taken to prevent further damage.

IV. How to prevent Cankerworm infestations?

There are several methods that can be used to prevent cankerworm infestations. One effective method is to use sticky bands around the trunk of the tree to trap the caterpillars as they crawl up the tree to feed. Pruning trees to remove egg masses in the fall can also help prevent cankerworm infestations. Additionally, maintaining the overall health of the tree through proper watering and fertilization can make it less attractive to cankerworms.

V. How to treat trees affected by Cankerworms?

If a tree has already been affected by cankerworms, there are several treatment options available. One common method is to use insecticidal sprays to kill the caterpillars. These sprays should be applied when the caterpillars are actively feeding on the tree. Another option is to introduce natural predators of cankerworms, such as parasitic wasps, to help control the population. It is important to consult with a professional arborist to determine the best course of action for treating trees affected by cankerworms.

VI. Are there natural predators of Cankerworms?

Yes, there are natural predators of cankerworms that can help control their population. One common predator of cankerworms is the parasitic wasp, which lays its eggs inside the caterpillars, eventually killing them. Birds, such as chickadees and warblers, also feed on cankerworms and can help reduce their numbers. By encouraging natural predators of cankerworms in the environment, it is possible to control their population and minimize the damage they cause to trees.