Spongy moth caterpillar on a leaf

Spongy Moths (formerly Gypsy Moth)

Updated as of April 6, 2023

Spongy Moth (Lymantria dispar dispar) — formerly known as gypsy moth — is a destructive forest pest responsible for killing millions of oak and other trees across the state.

  • Females lay their tan egg masses in June & July, which hatch the following year at the end of April to the beginning of May.
  • Egg mass surveys are recommended for late summer to fall but can be done throughout winter.
  • For foliar treatments, a week or two after hatch is the recommended treatment time depending on the insecticide being used.

In 2021 & 2022 there were high populations and heavy impacts in central & northcentral PA, the trend continues in 2023. The DCNR Bureau of Forestry will treat over 290,000 acres by aerial application of insecticide this spring.


If you are interested in setting up your own private spray program, please refer to the links below:

Guide to Conducting a Private Spongy Moth Suppression Program provided by DCNR

Aerial Applicators Licensed to Work in Pennsylvania provided by DCNR

DCNR Service Forester to Each County

Guide to Spongy Moth Egg Mass Surveying

Close up of female adult spongy moth and egg mass on tree bark
Female adult and Egg mass
Spongy Moth Caterpillar on a branch
Spongy Moth Caterpillar
2023 map of spongy moth suppression programs completed in Pike County

A clean and adequate supply of water is essential to maintaining good health.


Water conservation…Every Drop Counts! Install low flow plumbing fixtures and repair leaks. Take short showers instead of baths. Turn the faucet off while brushing your teeth.