Mission: Winter Moth


Research Question

Where in Maine is the Winter Moth?

You're invited

The Maine Forest Service wants us all on the look out for winter moths. November to January is a good time to find adult moths on trees and near lights. Winter Moth was first reported in Harpswell in 2011 by a concerned citizen, and has since been found on Vinalhaven Island. Winter moths recently invaded eastern Massachusetts in huge numbers, defoliating and killing maple, oak, ash, and apple trees. They like blueberry bushes, too. Early detection is key, so please keep your eyes on tree trunks and outdoor lights for this invasive moth.


Mission steps

1. Print the Winter Moth ID card

2. Print an Upland Species Survey datasheet

3. Find a maple, oak, ash, apple, or crabapple tree. Blueberry bushes and roses are good places to look too.

4. Depending on the time of year, look for the moths at lights and on tree trunks, caterpillars webbed into leaf buds and flowers or feeding on leaves, or cocoons buried in the soil.


5. Keep in mind that there is a native species look-alike. Invasive Winter Moth (Operophtera brumata) and native Bruce spanworm (Operophtera bruceata) look very similar at all life stages. They require dissection and DNA analysis to tell them apart. Because of this, the Maine Forest Service has asked us to post both species to the website as "Operophtera spp."

6. Go to your My Vital Signs page (link at top right) to add your "Operophtera spp. found" or "Operophtera not found" observation


Why this Mission matters

It's difficult to predict where infestations will occur as the Winter Moth can be moved unknowingly. The inchworm caterpillars (larvae) feed on leaf buds and flowers of hardwood trees, fruit trees, and blueberry bushes. They defoliate trees in the spring, then drop to the ground and spend all summer and fall buried in the soil in cocoons. In the soil, they can be easily transported from place to place with landscape plants. Caterpillars can be inadvertently moved on cars and boats.

Massachusetts has released a parasitic fly to control the winter moth across the tens of thousands of acres of forest it is impacting. Maine Forest Service is working with researchers from Massachusetts to establish the same bio-control for Maine infestations.

With your help, Maine Forest Service will be better able to develop a response plan in the early stages of an infestation. This provides many more options for managers, and may save trees and state resources.

Direct from the Maine Forest Service:


    Several hundred acres of Winter Moth-caused hardwood defoliation has been mapped from the ground in Harpswell Neck. More work is needed to determine how well established this species is in Maine. read more....

Want to know and do more?


You went into so much detail when describing the winter moth. We at Green Team 1 think you have the potential to become a scientist. Great research, and keep up the amazing work.

Here's a recent blog post on winter moth from David Epstein, a meteorologist in Boston. Have you seen winter moth larvae like these out and about lately eating leaves of crab apple, cherry, and maple trees?


Here is a cool resource to see county level observations of forest pests from across the country http://foresthealth.fs.usda.gov/portal/Flex/APE

This shows where some of those species that haven't been found in Maine yet, have been found. I'm not sure if it's totally up to date since I didn't see red pine scale found in Maine.


That is such a neat resource!!

I think I will have the students on the look out for the winter moth. I don't have the one I saw to send in for a positive ID, but I think this is a species the students can keep their eyes open for.

This is really cool info about the winter moth. Thanks for the great infermation.

Do you plan to be on the look out in your area?

I will try to search my area fo the winter moth as it will help our community get rid of these invasive species.