By Linda Williams, DNR Forest Health Specialist, Woodruff
Linda.Williams@wisconsin.gov,  920-360-0665

You may already be seeing the web nests created by eastern tent caterpillars, which hatch early in the spring and start feeding on emerging leaves as the weather warms up.

Eastern tent caterpillars can sometimes be mistaken for forest tent caterpillars or spongy moths. Check out the DNR’s comparison fact sheet, which includes pictures for identification and control options.

If you see the web nests of eastern tent caterpillars and want to control them, it is not necessary to prune the branch out of the tree. Pruning a branch would likely do more long-term damage to the tree than the caterpillars would do by eating the leaves.

When caterpillars eat a tree’s leaves early in the growing season, the tree will send out new leaves if it has the energy to do so.

You should also avoid burning web nests out of the tree. While this may feel satisfying, it poses a risk of starting a wildfire and harming the tree.

Instead, homeowners can squish the caterpillars within the web to control them (we recommend wearing gloves since their hair can be irritating). Homeowners may also pull the web out of the tree and put it in a bucket of soapy water for an hour or so to kill the caterpillars or spray Btk (Bacillus thuringiensis var. kurstaki), a caterpillar-specific pesticide.