How to Kill Tent Worms

Tent worms are tiny insects that can look like caterpillars. They are usually found during the spring, and transform into moths in around two weeks. However, they can do extreme damage to trees and other vegetation in this short space of time. Tent worms can be destroyed by commercial insecticide sprays, or they can be removed from the affected trees and drenched in homemade insect killers.

Things You'll Need

• Gardening gloves
• 2 foot long tree branch or wooden stick
• Thick garbage bag
• Dish soap
• Bucket
• Insecticide

Instructions

1. Put on a pair of gardening gloves before approaching areas effected by tent worms. Tent worms do not carry diseases that can spread to humans, but their hair bristles can act as an irritant to the skin.

2. Shine a flashlight around your garden trees to identify egg cases and nests. The nests are white and furry in appearance. They are easiest to find during the fall, when the leaves fall from the tree and make the infestations more visible. Early morning is the best time of the day to target tent worms as most will still be in their nests. Tent worms are typically around 2 inches long and predominantly black or brown in color. They also have manes of soft bristly white hair running along their bodies.

3. Pick the eggs and nests out by hand and place them in a heavy duty garbage bag. Use a tree branch to remove larger nests. Wind the nest around the tip of the tree branch and drop both into the garbage bag.

4. Drop the nests and eggs into a bucket of water mixed with three or four tablespoons of dish soap. This should kill the tent worms so they can be disposed of in the garbage.

5. Apply insecticide to trees where large, persistent infestations of tent worms occur. Pour an insecticide containing the active ingredient Bacillus thuringiensis into a spray can. Spray it on the tree foliage and directly onto the tent worm nests.

Tips & Warnings

• Make your garden more welcoming to birds. Install a bird aviary or put out crumbs and seeds. Birds are a natural enemy of the tent worm and will reduce their population by eating them.

• Never use fire to deal with a tent worm problem. Fire around trees and garden foliage can result in serious damage to your garden and surrounding properties.

References

• Washington State University: Western Tent Caterpillar Update
• Washington State University: Western Tent Caterpillar Update: Biological Control
• Gardening Know How: Tent Worms: Tent Caterpillar Home Remedy
• Washington State University: Biology and Control of Tent Caterpillars
• Texas Agri Life Extension Service: "WORMS" Are Really Forest Tent (Less!) Caterpillars