Sasha CampbellDuring an outbreak, spongy moth caterpillars (formerly known as gypsy moth caterpillars) will feed on many different trees and shrubs [1].
The caterpillars can also wreak havoc on other plants and become an annoyance in your yard. However, there are many natural and eco-friendly remedies to help control them.
How to Get Rid of Spongy Moth Caterpillars Naturally
Below are some home remedies and natural solutions that you can try.
1. Yard Clean-Up
Start by cleaning up your yard. Pick up fallen branches, twigs, and other yard waste.
Female spongy moths may lay their eggs on tree trunks, woodpiles, fences, outdoor furniture, and other sheltered places. Cleaning up your yard makes it harder for them to find places to lay eggs.
The eggs are laid in masses, and those masses can contain hundreds of eggs [2]. You may spot these during cleanup.
2. Spinosad
This biological insecticide affects the nervous system of certain insects. It causes paralysis, killing them in 1 to 2 days.
Spinosad can be used in organic gardens, but it is toxic to bees. Always follow the directions on the label for proper application.
3. Soap and Water
A little soap-and-water solution is a great home remedy for many pest problems.
Once you’ve spotted these caterpillars, fill a bucket with water and a little dish soap. Put on gloves and pick caterpillars and egg masses off trees and plants. Drop them into the bucket.
You can also make a DIY spongy moth caterpillar spray by combining 5 tablespoons of dish soap with a gallon of water.
Spray this homemade soapy water solution directly on the critters.
Direct contact with the spray may kill some caterpillars, especially smaller ones, but repeated applications may be necessary.
4. Bacillus thuringiensis (Bt)
Bacillus thuringiensis will kill caterpillars when they ingest it. However, the product should be applied according to the label instructions.
You’ll likely achieve the best results by spraying when caterpillars are young.
Spray Bt on plants when the caterpillars are still small. It works best in the evening because sunlight can weaken it. Apply once you spot the caterpillars.
Caterpillars usually stop feeding shortly after ingesting Bt and die within several days. Repeat applications may be necessary according to label directions.
Bt is slow-acting but effective.
5. Scrape Off Egg Masses
Spongy moth egg masses are covered in hair. Therefore, wear gloves to scrape them off the fuzzy eggs, as the hairs can be irritating.
Also, avoid scraping egg masses onto the ground, where they may survive. Instead, put them in a container of soapy water to soak for about two days.
Dispose of them afterward.
6. Horticultural Oil
Horticultural oil may help smother exposed egg masses if applied thoroughly. Still, scraping and destroying those egg masses is usually a more reliable method.
Purchase this as a ready-to-use spray and apply it according to the instructions that come with the product.
Horticultural oil is a multi-use product for addressing a range of pest problems. Use a bottle sprayer to apply it to the infested area.
However, ensure you spray thoroughly, even into crevices. The spray needs to make direct contact with the moth eggs to be effective.
7. Pheromone Traps
Adult moths are not the cause of the defoliation of trees. However, pheromone traps can help monitor moth activity.
These traps are most useful for monitoring adult moth activity and detecting infestations. They may capture some males, but they are generally not seen as a stand-alone control method during large outbreaks.
For assembly, follow the instructions that come with your purchase. Hang them in the trees when the pests are active.
8. Molt-X
This product is an effective knockdown spray. It contains 3% azadirachtin, a compound derived from neem tree seeds.
Molt-X is not neem oil, so it doesn’t have fungicidal properties. However, its triple action slows insect feeding, disrupts molting, and acts as an insect repellent.
You can use it as a foliar spray or as a soil drench for potted plants and trees. It generally leaves minimal visible residue when used according to label directions.
Molt-X is also suitable for indoor, greenhouse, or outdoor use.
9. Bug Buster-O
Another effective knockdown spray; this natural pesticide contains pyrethrins.
When used according to label directions, it can be applied to many vegetables, herbs, fruit trees, flowers, and ornamentals.
10. Trichogramma Wasps
Trichogramma wasps are small, helpful insects that parasitize moth eggs.
They lay their eggs inside the eggs of many moth species, including spongy moths. The wasp larvae then feed on the moth eggs, preventing new caterpillars from hatching.
You can purchase these moth egg parasites from various suppliers and release them according to the package instructions.
Moreover, these parasitic wasps control other pests, including cutworms, borers, and armyworms.
11. Birds
This is another natural spongy moth control method—and an attractive one.
Many birds provide their young with caterpillars during the breeding season. This makes them valuable natural predators of spongy moth larvae.
Plant attractive plants like sunflowers to bring birds to the garden. You can also set up a bird feeder on the lawn. A birdbath or small water feature can also help attract birds to your yard.
Birds such as blue jays, chickadees, orioles, and cuckoos may help eat spongy moth caterpillars.
12. Cover Woodpiles
In the summer and fall, female spongy moths often lay eggs on firewood stacks.
Therefore, cover your woodpiles with a tarp or similar material to make them less attractive to egg-laying moths.
13. Burlap Bands
As spongy moth caterpillars grow larger, they often crawl down tree trunks. They do this during the day to seek shelter from heat and predators.
You can take advantage of this behavior by wrapping a strip of burlap around the trunk of infested trees at about chest height. Fold the top half of the burlap over the bottom half to create a flap where caterpillars can hide.
Check under the burlap daily. Remove any caterpillars you find and drop them into soapy water to kill them.
This method works best when combined with other control measures. For example, you can scrape egg masses and apply Bt or spinosad to young caterpillars for better results.
14. Neem Oil
Neem oil may help stop young caterpillars from feeding and growing. For best results, use it early in an infestation and follow the label directions.
It can be purchased as a concentrate and applied to infested plants. Be sure to coat both the upper and lower leaf surfaces.
Takeaway
Spongy moths (formerly known as gypsy moths) were accidentally released in North America in 1869 [3]. Since then, they have spread and infested many areas of the United States.
A healthy tree can usually survive a single season of defoliation. However, repeated defoliation over several years can weaken trees, making them more susceptible to disease and other stresses.
Using several natural control methods together often works best for protecting your trees and plants.
EXCELLENT! Thank you. All but the Spinosad. I have found that people will take the quick way and think that the bees will not suffer.
But it is in the arsenal against gypsy moths.
I am promoting bee population by encouraging the growth of snowdrops (or are they bells). Two weeks ago, the snowdrops were attracting bees. In this weather! In NJ.
I am glad that this is your dilemma and not mine. All the best.
What keeps chipmunks out of flower beds?
Try these suggestions: https://drecampbell.com/natural-ways-get-rid-chipmunks/