A native species, cankerworms go through cycles of infestation and outbreak ranging from 2 to 7 years with periods of low population from 13 to 18. No major population outbreak has occurred since the 1970s, with isolated outbreaks occurring occasionally. The pest is often considered more of a nuisance
than a severe threat.
Threat to Trees
Begins in early spring or fall and feeding occurs for about a month
Signs & Symptoms
Wingless females and egg masses on trunks in January and February, crown defoliation due to feeding and limb dieback after consistent defoliation of three or more years. Young, weak or newly translated trees are most susceptible.
Small larvae feed on small parts of leaves, older larvae consume entire leaves. Fall cankerworms are often considered more of a nuisance with caterpillars spinning to the ground on silk strings and climbing walls during spring and fall months.
Throughout United States