Tent Caterpillar nests in Black Walnut tree

Asked August 16, 2018, 12:12 PM EDT

I have a mature Black Walnut tree in my yard that has had nests of tent caterpillars the last three years, one each for two years and at least four this year. What little I know suggests there is little effect on the health of the tree. I know friends with fruit trees that bag and burn nests on their smaller trees. My tree's nests are twenty five or thirty feet in the air so that is not an option for me. In 1987 Mpls. Park Board planted a grove of walnuts across the street in Powderhorn Park. Some have started to produce nuts. QUESTION: Should I be concerned the caterpillars could infest and harm the smaller trees if not controlled?

Hennepin County Minnesota fall webworm black walnut tent caterpillars horticulture

2 Responses

The web-dwelling larvae found on black walnut trees at this time of year are probably fall webworms. Although the webs can be unsightly, it's true that the insects' feeding has little or no effect on a tree's health and no control is needed. The webworms do not pose a threat to the trees in Powderhorn Park.

Learn more here:


Thank you. I will inform my concerned neighbors.