Tree problems · Insect

Spongy moth: signs and what to do

Spongy moth is an insect pest, often seen on oaks, aspen, birch. Look for: tan or buff, fuzzy egg masses on trunks, branches, rocks, fences and outdoor items in fall, winter and early spring.

General information, not a diagnosis. A certified arborist or your county extension office can confirm.

Insect
Oaks
Aspen
Birch
Linden
Maples
Many other trees and shrubs

Signs to look for

Tick what you see. More ticks make it more likely, but only an on-site look can confirm.

Tan or buff, fuzzy egg masses on trunks, branches, rocks, fences and outdoor items in fall, winter and early spring
Hairy caterpillars with pairs of blue and red dots on their backs in spring and early summer
Leaves chewed to ragged shapes, sometimes whole trees stripped
Many small dark droppings on the ground and on cars or decks below infested trees
Caterpillars crawling on trunks, or hanging from silk threads
A second leaf-out later in summer on trees that were stripped early

0 of 6 signs ticked. Ticks stay in this browser only.

Season

Eggs overwinter in masses. Caterpillars hatch in spring and feed on leaves until early summer. Moths fly and lay eggs in summer.

How it spreads

Young caterpillars can drift on wind on silk threads. People move egg masses by accident on firewood, vehicles, trailers and outdoor household items. Federal and state quarantine rules can apply to moving items from some areas.

Where it is found

Spongy moth, formerly called gypsy moth, is an invasive insect from Europe that is established in much of the northeastern and upper Midwestern United States, with treatment programs along the edge of its range. Check your state official map; ranges change.

Official sources

What to do

1
In fall, winter or early spring, scrape egg masses into a bucket of soapy water. Do not just drop them on the ground.
2
In spring, wrap a burlap band around the trunk. Caterpillars hide under it by day, and you can collect and kill them.
3
Ask a licensed applicator about a caterpillar-specific spray in spring for valuable trees. Timing matters, so call early.
4
Do not panic about one defoliation. Healthy deciduous trees often leaf out again, but repeated stripping can stress or kill a tree.
5
Check your outdoor items, such as campers, firewood and lawn furniture, before leaving a quarantine area.

Safety first: do not climb, do not cut near power lines and do not use a chainsaw on storm-loaded wood. Call the utility for downed lines and 911 if anyone is in danger.

Prevention

Keep trees healthy with deep watering in dry spells and proper mulch. Inspect and clean outdoor items before moving them. Remove egg masses you find. Dry weather in spring can help the moth, so be extra watchful then.

When to call a pro

Call a pro when a valuable tree is losing most of its leaves, when you cannot reach the egg masses, or when you want a spring treatment plan. Also call if the same tree is stripped for several years in a row.

Not sure who to call? Read how to hire a tree service or check is my tree dangerous?

Trees it affects

Usually seen on: Oaks, Aspen, Birch, Linden, Maples, Many other trees and shrubs.

See all species in our tree library, or pick a tougher tree with the tree picker.

For tree companies

How to explain spongy moth to a customer

Explain that defoliation looks scary but healthy trees often recover from one year of it. Focus on protecting high-value or already stressed trees, and on timing the spring treatment. Give owners a simple egg-mass scraping tip so they feel in control.

Send this page to the customer after your visit so they can read the signs in plain words. See also selling plant health care and the job photo checklist.

Questions

Is a spongy moth the same as a gypsy moth?

Yes. The name was changed to spongy moth in 2022. The insect is the same.

Will the trees die from the defoliation?

Healthy deciduous trees often grow new leaves. Repeated years of stripping, drought or other stress can kill a tree, and evergreens are more at risk.

When should I scrape off egg masses?

Any time they are there, but fall to early spring, before they hatch, is best. Scrape them into soapy water so they cannot hatch.

Are the caterpillars harmful to touch?

The hairs can irritate skin or cause a rash in some people. Wear gloves and avoid rubbing your eyes.

Do sprays harm bees?

Some caterpillar-specific products target young caterpillars and have less effect on other insects, but timing and labels matter. Ask a licensed applicator which product they use.

Why do I need to inspect my camper or firewood?

Egg masses stick to vehicles and outdoor items and can be carried to places where the moth is not yet found. Quarantine rules can apply in some areas. Check with your state office.

Can Lirevon diagnose spongy moth on my tree?

No. Lirevon is a remote marketing team for tree service companies and does not do tree work. This page is general information, not a diagnosis. A certified arborist or your county extension office can confirm what is wrong with your tree.

How do I find a good local pro for this?

Search Google Maps for certified arborists or tree services near you, read their reviews and ask for proof of insurance. Get two or three written quotes. Our guide on how to hire a tree service lists the questions to ask.

When customers spot spongy moth, they call

Make sure someone answers. Missed-call text-back, lead follow-up, booking and review requests, set up for you. See our services and pricing.

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