Stop or Prevent a Gypsy Moth Caterpillar Infestation

Along with Memorial Day cookouts and pollen-covered windshields, a sure sign of late spring and early summer is the gypsy moth caterpillar. When fully grown, they will be approximately 2 inches long, very hairy and have five pairs of blue dots followed by six pairs of red dots along its back. Beyond looking disgusting and crawling all over everything, they also cause severe damage to hardwood forests and urban landscapes in much of the Eastern United States. These pests defoliate a million or more forested acres annually.

Defoliation by gypsy moth caterpillars can weaken trees. By destroying their leaves, the trees are not able to manufacture food. Weakened trees are susceptible to bark beetles and root diseases that can kill them.

As if that weren’t bad enough, newly hatched caterpillars can also be a health hazard. Their hairs contain histamine and are highly allergenic!

Luckily, there are some simple steps that you can take to protect your trees from these hungry late-spring invaders.

Protect Trees From Caterpillars

Once temperatures are above 60 degrees Fahrenheit, caterpillars will hatch from the eggs laid the previous summer. Then they crawl up trees and out on the limbs to eat the leaves. These caterpillars primarily feed at night time to protect themselves from extreme heat and predators like birds. Even though you may not see them in action during the day, this does not mean that your yard is free of them.


duct tape and tanglefootOne way to prevent gypsy moth caterpillars from eating your tree’s leaves is to block their climb the tree trunk.  The Tanglefoot® product that Koopman carries is the perfect product to use as its adhesive composition traps the caterpillars as they try to crawl over it. Additionally, it is made from all natural ingredients, so no pesticides or chemicals are going to harm your trees!

Begin by wrapping two widths of duct tape, some aluminum foil, or Tanglefoot’s own tree wrap around the trunk of the tree about chest height from the ground. Be sure to tuck the tape tightly into every fissure and crevice in the bark.

Then smear the Tanglefoot® around the center of the duct tape, using a popsicle stick or a wooden shim, so you don’t get any of the product on you.

Before the long, the trapped caterpillars will begin to stack up. Scrape them off into a jar that contains a couple inches of water and some dish detergent. Though this takes some time, it is a highly effective method.

Caution: Don’t smear the Tanglefoot® directly on the tree, as it will discolor the bark and could cause damage.


Another method is to use a controlled spray to kill gypsy moth caterpillars. This is a particularly useful approach if you didn’t get your Tanglefoot barriers up early enough and caterpillars are already feeding in your trees. Correct timing and application are the most essential elements for success. Read and follow label directions exactly.

bonide gypsy moth solutions 3w1hThe Bonide products Thuricide®, Eight® and Captain Jack’s Dead Bug Brew® are all well suited for this purpose.

Thuricide® (also often referred to as “BT”) is most effectively applied when gypsy moth caterpillars are still small or at the first sign of infestation. Create a mix 4 teaspoons of Thuricide® per gallon of water, then apply using a pump sprayer. Apply the mix thoroughly to the upper and lower leaf surfaces, but not to the point of excessive runoff. Be sure to agitate the mix regularly while spraying. The treatment can be repeated in two weeks.

Eight® provides economical, contact and residual insect control for up to 4 weeks.  It may be applied to homes and other areas to stop infestations. It is available in concentrate, ready-to-use spray bottle, and hose-end sprayer formats. If using the concentrated format, use 1 Fl. oz. in 1 gal. of water. Apply as a thorough spray, wetting leaves and branches to the dripping point. Try to penetrate dense foliage. Spray in the late afternoon or evening, when the temperature ranges from 50˚ to 75˚F and when there is little or no wind. Spray at the first sign of insects. Repeat as necessary; use intervals of 4-8 days. Do not exceed 16 applications per season.

Captain Jack’s Dead Bug Brew® contains Spinosad, a naturally-derived insecticide used around the world for the control of a wide variety of insect pests. It has even been approved for use in organic agriculture by numerous national and international certifications!  It is available in concentrate, ready-to-use spray bottle, and hose-end sprayer formats.If using the concentrated form, make sure to carefully follow the mixing guidelines on the product label. Using a pump sprayer, apply the mix uniformly onto the leaves to the point of runoff. Uniform coverage of upper and lower leaf surfaces is essential for effective insect control.

Encourage Birds To Visit Your Propertybird eat caterpillar

There are a variety of bird species known to prey on gypsy moth caterpillars, including bluejays, blackbirds, nuthatches, cuckoos, chickadees, towhees, vireos, northern orioles, robins, catbirds. By selecting a high-quality Blue Seal bird feed from Koopman that these species prefer to consume, you can draw these birds to your property. Once in the yard, these birds will find a juicy caterpillar to be a delectable treat.

There are several preventative actions that you can take to disrupt the gyspy moth life cycle, especially the laying of eggs by the adult moths.

Interrupt The Gypsy Moth Life Cycle

Throughout the rest of the year, there are several easy preventative steps you can take to disrupt the gypsy moth life cycle and prevent your property from being overrun with newly hatched caterpillars during the next spring.

gypsy moth egg massKeep Your Yard As Clean As Possible

Remove piles of old wood, dead branches, stumps, etc., where the adult female moth is likely to lay egg masses in the late summer. Also, remove any hiding places on the trees themselves; ivy, bark flaps and dead branches.

Destroy Any Egg Masses

NOW is your first chance to stop the destructive Gypsy Moth Caterpillar!  Use Bonide’s Organic All Seasons Oil and cover all visible egg sacks in your area. Do not remove the egg sacks from the tree, spray them right where they are. All Seasons Oil can be used as a concentrate (then added to water and sprayed) or also available in a ‘ready to spray’ and a ‘ready to use’.

The All Seasons Oil is a surfactant and will coat the eggs eliminating the oxygen and prevent the eggs from hatching.

This will need to be done before mid-April. Your ounce of prevention by mid-April can prevent thousands of pounds of leaves from being devoured and the eventual death of the tree.

Obviously, these pesky critters travel, so you’ll still get them in your yard this year.  But every sack you soak today will make a difference going forward!! Hopefully, you are able to get all the egg masses coated, and stop as many of the caterpillars from hatching.

For the ones that survive or travel to your yard use Bonide’s Captain Jack’s Deadbug Brew also approved for organic gardening. Captain Jack’s is the best product available for killing the Gypsy Moth Caterpillar.

Apply as a thin film coating on the top and bottom of the leaf. When the caterpillar chews the leaf, it will die.

This can be used as a concentrate (then added to water and sprayed) or also available in a ‘ready to spray’ and a ‘ready to use.’

Good luck!!!


Read the full blog here

Caution:  Wear a safety mask and glasses when scraping egg masses. This action can expose the scraper to allergenic hairs covering the mass.

Wrap Up

By attacking the gyspy moth at each stage of its life cycle, you can begin to make headway against an established population. To stock up on all of the products you’ll need to combat these hungry, hairy invaders, stop by your local Koopman Lumber store! We’ve got the friendliest, most knowledgeable staff around. We’ll be glad to help you arm yourself with the tools and know-how you need to protect your trees.

  • Marilyn

    And when you have acres of trees? What then? If the town isn’t willing to help, exactly how can one couple protect multiple wooded acres?

    • Koopman Lumber

      Hey Marilyn, we’d love to help you and give you a plan to take these pests down! Why don’t you swing by one of our stores and talk to one of our helpful employees to figure out the best method for you!

  • David Chenot

    Kind of late but maybe next year

    • Koopman Lumber

      It’s not too late to stop the spread and help for next year! You can still get rid of the existing caterpillars and eliminate eggs to help between now and then. Thanks for reading!


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