Bug Identifier

Moths & Butterflies

Spongy Moth

Lymantria dispar

020406080
Body length in millimeters. Shaded bar shows the typical adult range.
Scientific nameLymantria dispar
GroupMoths & Butterflies
Size35–65 mm (up to about 2.6 in)
Colors Brown, Tan and White
Legs6 legs
WingsYes
Where foundTrees or shrubs and Woods or trails
Most activeSummer
BitesNo
StingsNo
Risk levelNuisance

How to identify it

The spongy moth is a large member of the moths & butterflies group. Wings covered in fine scales and a coiled, straw-like tongue. Check for these three features:

  1. Hairy caterpillars with five pairs of blue dots and six pairs of red dots
  2. Tan, fuzzy egg masses on bark, rocks and outdoor furniture
  3. Brown males and white females in midsummer

About this bug

Formerly called the gypsy moth, an invasive moth whose hairy caterpillars strip the leaves from oaks and other hardwoods. Caterpillars carry paired blue and red dots along the back.

You'll usually find spongy moths on trees and shrubs and in woods and along trails. They are most active in summer.

Is it dangerous?

Caterpillar hairs can cause itchy rashes, and heavy outbreaks strip trees of their leaves.

Our rating: Nuisance, meaning it is a nuisance pest but not a health threat to most people.

When you'll see spongy moths

Spongy Moths are most active in summer. Summer heat speeds up development, so populations can grow quickly.

Typical places to check: trees or shrubs and woods or trails.

About moths & butterflies

The spongy moth is one of the moths & butterflies. Moths and butterflies have wings covered in tiny scales and go through complete metamorphosis. The caterpillar stage does all the feeding and damage, while adults sip nectar or, in some species, don't eat at all.

In pantries and closets, the moths you see flying are a signal. The real problem is the larvae feeding in food or fabric nearby.

What to do about it

  1. Scrape egg masses into soapy water from fall through spring
  2. Wrap tree trunks with burlap bands and remove caterpillars daily
  3. Have an arborist evaluate Btk sprays for heavily infested trees

Frequently asked questions

What does a spongy moth look like?

Hairy caterpillars with five pairs of blue dots and six pairs of red dots. Adults measure 35–65 mm (up to about 2.6 in).

Does the spongy moth bite or sting?

It does not bite. It does not sting. Caterpillar hairs can cause itchy rashes, and heavy outbreaks strip trees of their leaves.

Where do spongy moths live?

Spongy Moths live on trees and shrubs and in woods and along trails.

When are spongy moths most active?

Mostly in summer.