Tent Caterpillar FAQs

Does the spray make the tents go away?

No, the growth of the tree or shrub and the elements ~ wind, rain, and sun ~ will disintegrate the tents over time.

Do the caterpillars move into my trees from the neighbor's?

No, the tents that have developed in your trees are from egg masses that the adult moth laid in your trees during the summer of the previous year.

Is there something we can spray on the trees before the caterpillars hatch out to keep them from hatching at all?

No, the environmental laws in Washington State are quite strict. There are currently no legal or approved products that will control the tent caterpillars while they are still in the egg stage.

Will one spray control my caterpillars?

Yes, most of the time. However, not all of the eggs hatch out at the same time. If we have given you a spray before all of the eggs in the egg masses have hatched, you may need a second spray.

Can the caterpillars kill my tree?

No, with a couple of exceptions. A tree that was already in poor health may not be able to withstand being defoliated by caterpillars. Most healthy trees would have to be completely denuded for 2-3 years in a row before a caterpillar infestation would cause the tree to actually die. Lately, most of the caterpillar infestations in this area have not been that severe.

If I see caterpillars in my yard after the spray, does that mean my spray was ineffective?

No, once the live caterpillars have eaten their fill, they come down out of the trees and look for a place to cocoon. At that point, the caterpillars are crawling down from trees and shrubs everywhere. They will crawl into your yard or wherever they choose to find a place to cocoon. If your spray was effective, you will see no live caterpillars sitting on the outside of the tents.

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