Tent caterpillars

Asked August 20, 2020, 2:35 PM EDT

I have a large nest of tent caterpillars very high in my birch tree. It is impossible for me to get to it. Whom would I call to have it removed? Or do I need it removed? Will it just disappear in the winter and they’ll be no problem? Do I call a tree person or a pest person? Can you give me a recommendation for someone in Multnomah county please Thanks

Multnomah County Oregon

1 Response

Tent caterpillar populations build up and peak every 2-3 years. Although they're very unsightly, and can defoliate trees, the trees seem to be able to recover well. The trees will leaf out as expected in the spring. As the populations of tent caterpillars build up so do the parasites, predators and viruses that destroy them. You can prune off the tents, but the most effective time to do this is in the spring when populations are small, and easier to control.

The best time of day to prune out their nests now is early morning or evening when the caterpillars have returned to the nests for the night. An ISA (International Society of Arborists) certified arborist is best able to prune out the nest while preserving the tree. This site https://pnwisa.org/hire-an-arborist/isa-certified-arborist-directory/ allows you to contact arborists in our area. We recommend you talk with at least 3 to get the best person for your job.

This article has additional information and pictures of tent caterpillars, Western Tent Caterpilllar https://www.oregon.gov/ODF/Documents/ForestBenefits/WTC_2017.pdf. In the fall they lay their eggs in hardened areas around branches. There is a picture of one in the article. If you find one of these, destroying it will decrease the population of caterpillars next spring.