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Maine Forest Service

Browntail Moth: What can I expect in 2026?

* Browntail moth populations have been declining... but will this trend continue in 2026? [ #link_3 ]
* How can I monitor browntail moth populations on my property? [ #link_6 ]
* How can I tell the difference between browntail winter webs and other species' webs? [ #link_4 ]
* The best way to remove browntail winter webs from trees: [ #link_5 ]
* I can't clip all the browntail winter webs in my trees. Where can I find resources for an arborist or pesticide applicator? [ #link_1 ]
* Upcoming Winter Web Survey 2026 [ #link_2 ]

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Browntail moth populations have been declining... but will this trend continue in 2026?

Browntail moth populations have been declining statewide since 2024. During aerial surveys this year, 4,935 acres of damage from browntail moth were documented primarily in Cumberland, Androscoggin, Kennebec, and Penobscot Counties. This is a slight increase in damage compared to 2,119 acres of damage that was documented last year.

Many insect species in Maine undergo population changes, where populations grow until they collapse, and then begin to grow again. Although we have documented a significant decrease in browntail moth populations, they will not remain low forever. The browntail moth will always be present to some extent in Maine's forests, and we expect the populations to increase again.

In late summer 2025, there were periods of extreme drought statewide. It is unclear how these drought conditions may have affected browntail moth caterpillars. Drought conditions can favor browntail moth population increases as the dry weather negatively affects the pathogens that can impact the population. However, other factors may contribute to continued lower populations.

BTM 2025 aerial survey [ [link removed] ]

In 2025, aerial survey revealed browntail moth damage to roughly 4,935 acres in Androscoggin, Cumberland, Kennebec, and Penobscot Counties.

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How can I monitor browntail moth populations on my property?

Even though browntail populations remain low, scouting trees for their winter webs is the most important step in understanding possible impacts in your backyard. Because browntail caterpillars overwinter inside their winter webs on their host trees, it's important to look for and remove the webs before the caterpillars emerge in spring.

*Here's how to scout for winter webs*:


* On a sunny day, check for clumps of leaves at the tips of browntail moth's host trees: oak, birch, cherry, crabapple, and sometimes other fruit and hardwood trees.
* Browntail winter webs are typically 2-5 inches long and have a distinct white silk covering that protects them from the harsh Maine winters - this white silk is easier to see on a sunny day.
* Count (or estimate, if heavily infested) the browntail winter webs in each tree.

BTM winter web in hand

Browntail moth winter web on host shrub in Newport, ME.

In heavily infested trees (trees with 100+ winter webs), like the ones in the photo below, winter web removal may not be appropriate. Instead, pesticide applications may be considered if these trees are in a high-traffic areas such as your dooryard or the front of your business building. For more information on pesticide applicators, please refer to the following section: "Where can I find resources for an arborist or pesticide applicator?"

BTM winter webs in trees

Many browntail moth winter webs at the tips of tree branches in Augusta, ME.

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How can I tell the difference between browntail winter webs and other species' webs?

In 2025, fall webworm ("Hyphantria cunea") had a banner year and their webs were broadly mistaken for browntail moth webs in late summer. Fall webworm is a native insect in Maine and they do not have toxic hairs (unlike browntail moth) and their webs are typically only an aesthetic concern.

Fall webworm do not use their webs in the winter season and these structures will naturally deteriorate as time continues. There are a few ways to tell the difference between these webs:

*Browntail Moth Winter Webs* *Fall Webworm Winter Webs*
* White silk present around web and attaching web to branch

* Matte white silk present

* Small clump of leaves, 2-5 inches long

* Large, nest-like bundle of leaves and debris, 3-15 inches long

* Tightly compacted web

* Loose, deteriorating web. May break open and fall to ground during winter from lack of use


 

Fall webworm web in winter.

A fall webworm web in the winter. Note: fall webworm webs are larger than browntail moth webs and do not have the white silk attaching the web to the branch.

*Still unsure about scouting for browntail winter webs in your trees?*


* Read a detailed fact sheet [ [link removed] ] explaining the difference between browntail webs, eastern tent caterpillar webs, and fall webworm webs.
* Email us at [email protected] <[email protected]?subject=BTM%20Observation> with photos of your trees with suspected browntail winter webs and we can help identify the webs on your trees for you.
* Watch our browntail moth web scouting & removal video for a step-by-step guide:

BTM Web Removal Video [ [link removed] ]

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The best way to remove browntail winter webs from trees:

You found browntail winter webs in your trees, now what? Remove them!


* *Remove webs that you can safely reach from the ground with an extendable pole pruner or pruning shears.*
* Be sure to wear protective clothing (long sleeves, gloves, eye protection, etc.) when removing webs to prevent a rash from the residual caterpillar hairs.
* For webs that are inaccessible, or hazardous to remove (e.g. requires climbing or near power lines/traffic), consider hiring a professional to remove the webs.

* *Collect clipped webs from the ground into a bucket.*
* Browntail caterpillars are alive inside the winter webs. Leaving clipped webs on the ground will not eliminate the caterpillars and they will still emerge in the spring.

* *Destroy the collected winter webs:*
* Fill the bucket of winter webs with soapy water and let it soak for a few days to kill the caterpillars inside, OR
* Burn the webs by carefully placing the webs into a contained fire.

BTM winter web removal

An extendable pole pruner is being used to reach browntail winter webs in a crabapple tree in Orono, Maine.

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I can't clip all the browntail winter webs in my trees. Where can I find resources for an arborist or pesticide applicator?

Browntail mitigation should be focused on high-traffic areas for the most impactful relief. If there are populations you want to manage, hiring a licensed professional may be helpful.

If you can't remove the browntail winter webs on your property, consider hiring a professional to assist with removal. *Winter web removals should be completed before the end of March.* Read our list of licensed arborists [ [link removed] ] and FAA-certified drone operators [ [link removed] ] who perform winter web removal throughout the state.

Licensed pesticide applicators may have a limited schedule for timely spring pesticide treatments to reduce impacts from browntail caterpillars. If you have browntail winter webs in your trees that cannot be removed, consider hiring a licensed pesticide applicator and get in contact with them in early winter. *Pesticide applications should take effect before the end of May to be effective.* Check out our list of applicators willing to treat browntail moth [ [link removed] ].

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Upcoming Winter Web Survey 2026

To understand where browntail moth populations are, we conduct winter web surveys during the winter season. We estimate total number of webs in trees alongside major roads in areas across the state. This information allows us to estimate areas that may experience impacts from elevated browntail moth populations.

These surveys are usually completed in March. After the winter web data is reviewed, it will be available on our interactive browntail moth map, which can help give you a rough idea about what browntail is doing in your community. Currently, the 2025 winter web map is available on our website:

BTM Interactive Map [ [link removed] ]



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