Browntail Moth Response
August 8, 2022 Update:
In the Bangor area, the female adult moths have laid their eggs and completed their life-cycle. We have not seen a moth in over a week. It is now safe to turn on your outside lights at night, again, without fear of attracting these moths to your property!
Anecdotally, the adult moth population seemed much less noticeable this year in Bangor. I took note of the number of adult moths around a security light that was on every night at Public Works and there were never more than 10 moths on any given morning. Our Service Request/Reporting system seems to support this as we only received 2 reports of moths in the month of July this year versus 57 reports last July. As I mentioned previously, I witnessed a number of caterpillar deaths earlier this year, due to fungal infection. This was just prior to the cocoon stage. I’m hoping the low moth observations may be due to a high death rate as they were entering cocoons. That is a very unscientific theory and is likely just hopeful thinking on my part.
Though I haven’t witnessed any egg sacs starting to hatch in Bangor, the Maine Forest Service has been seeing young caterpillars starting to feed around the State. They are very small (less than ¼” long) and hard to spot but they leave behind a telltale sign – skeletonized leaves.
These small caterpillars do not shed hairs like the larger ones and, therefore, do not pose a high risk to people. We are unlikely to be bothered by their hairs for the balance of the year. However, I am seeing a lot of old cocoons that still have tightly clumped leaved. When/If these open, they will likely release toxic hairs into the air. If you are trimming branches and disturb these cocoons, hairs from the caterpillar may emerge and cause problems for you. Similarly, if you are mowing your lawn or we experience strong winds, hairs that fell to the ground may get stirred up and cause problems.
Pesticide treatment this time of the year isn’t recommended due to the way these young caterpillars feed coupled with the difficult in identifying where they are active. If you choose to apply pesticide, please do so carefully or hire a State of Maine licensed pesticide applicator to minimize impact to non-target insects. Again, our best and safest bet to reduce the number of caterpillars and their toxic hairs next year will be winter web clipping after the caterpillars spin their winter nests.
You can always find the latest information about browntail moth in Maine by visiting the Maine Forest Service Knockout Browntail Moth page at Browntail Moth Euproctis chrysorrhoea : Forest Health & Monitoring: Bureau of Forestry: Maine DACF
Here’s a great picture, from the MFS, of the size of the BTM size this time of year.
Not caused by BTM but this is an example of a skeletonized leaf with bronze-copper color.
July 6, 2022 Update:
Adult browntail moths have begun to emerge from their cocoons over the last few days in Bangor. You will see the white moths have gathered on walls and objects each morning, nearly anywhere there is an outside light left on overnight. This will be especially true on the west side of the city where surveys have indicated a much more robust BTM population. As more of the moths leave the cocoon their numbers will grow and they will become much more noticeable.
(from Maine Forest Service website) (taken at Public Works 7/6/22)
Insect traps, bug lights, and other methods of attracting and catching the moths is sure to be ineffective and are more likely to encourage the female moths to lay eggs on your property. The use of bug zappers may also reduce the population of parasitic flies and wasps that are natural enemies of the BTM. The best thing you can do is to turn off your outdoor lights between 9:00 pm and midnight, when the moth is most active.
The City of Bangor has streetlights all over the city and most of these are adjacent resident properties. We will not be turning off these lights, in the interest of public safety. Additionally, there are not enough Electrical Division staff to turn off even a fraction of the lights before the BTM lays its eggs and dies. Future plans for street lighting include remote control options that may allow for dimming during certain hours. Unfortunately, we are not there at this time.
Stay tuned to this page for periodic updates about BTM in Bangor. For more information on the statewide BTM problem, please visit the Maine Forest Service Knock Out Browntail webpage.
June 23, 2022 Update:
Our observations in Bangor indicate that browntail moth is currently entering pupal (cocoon) stage. There are very few feeding larvae (caterpillars) being observed at this point. This means the caterpillars will not be actively shedding their barbed and toxic hairs into the environment much longer. The caterpillar hairs will be encased in the cocoon as it transforms into the adult moth. In July we should see moths emerging from the cocoon to mate. The good news is that the adult moth does not shed these toxic hairs. The bad news is that the process of breaking out of the cocoon allows the hairs from their old caterpillar body can be released into the atmosphere where they can affect people.
The adult moth is very recognizable with bright white wings and a brown fuzzy tail poking out from under the wings. The moth is attracted lights at night, especially between 9:00 pm and midnight. If residents turn off their porch lights they can avoid attracting the moth to their property. The male moth will cluster around lights and the females will hang back in tree foliage close to the lights. Residents can remove clustered moths (and caterpillars) using a vacuum with HEPA filter and a few inches of soapy water, allowing them to drown in the water for a few days before disposing of them. Removing the moths may feel satisfying but, unfortunately, it is not an effective population control method. The moths that cluster around lights are male and we will never be able to remove enough of them to prevent the females from mating and laying their eggs.
The moths will be laying eggs sacs of approximately 200-400 eggs in August. The eggs will hatch approximately 2 weeks later. These caterpillars will feed on leaves and you will see skeletonized leaves on affected trees. These trees will end up with winter webs in mid-late October as the caterpillars prepare for winter. During this early feeding period the caterpillars will shed hairs but the effect doesn’t seem to be as severe as in the spring.
Despite the fact that there will be fewer hairs being actively shed by caterpillars, there are still plenty of hairs already in the atmosphere, ready to cause a rash. These hairs will eventually be washed out of trees and into the soil but they remain active there. Raking your lawn, digging a hole, mowing, leaf blowing, etc. can all disturb these hairs and cause them to become airborne again. We recommend that people survey the area where they plan to work or recreate and look for signs of the browntail moth. Trees with old winter webs and cocoons made of leaves and silk are telltale signs that the caterpillar has been active there. If you must be in the area of that type of tree, please take precautions to prevent a rash. Working after a rain, or when there is heavy morning dew, when trees and the ground are wet means the hairs are less likely to become airborne. Long sleeves, long pants, socks that cover your ankles, closed toe shoes, gloves, and a hat with a brim that covers your neck are all methods of preventing the hairs from landing directly on your skin. Once you leave the affected area you should remove these clothes and put on fresh clothes. This will prevent hairs from moving through the clothes and being forced into your skin. Washing or showering with cool, soapy water can wash the hairs off your skin before they can get into your pores. Some people have experienced success with application of pre-contact poison ivy wipes and similar barrier creams on exposed areas of skin.
The City of Bangor is performing some very limited scope testing of pesticides to identify effective treatments. There will also be a winter web clipping program on public property again in the winter of 2022-2023. The City of Bangor has no program to provide browntail moth mitigation services on private property.
We encourage people to report browntail moth sightings whether they be caterpillars, cocoons, moths, or winter webs. Reports can be entered through our website at Request for Service - City of Bangor, ME (bangormaine.gov).
These reports are mapped with time/date stamps to allow us to gather real-time data that will help us determine the scope of the problem and develop cost effective counter-measures.
Please check in on this page regularly for updates. You can also monitor the Maine Forest Service website at Browntail Moth Euproctis chrysorrhoea : Forest Health & Monitoring: Bureau of Forestry: Maine DACF for more frequent updates regarding the problem statewide.
May 24, 2022 Update:
Browntail moths in the Bangor area have now exited their nests. Trees with winter nests are likely to be covered with tiny caterpillars that are growing fast. The recent windy weather has knocked a lot of the caterpillars out of trees so you may see a lot of them on the ground under the canopy of the tree, too.
It is well past the point where nest clipping is effective; the nests are now empty. Residents experiencing a large number of BTM caterpillars on their properties have a few options:
- Call a license insect pesticide applicator to apply pesticide to your affected trees
- Responsibly apply pesticide, yourself, to your affected trees
- Pray for a wet month of June to allow the natural enemy of the BTM caterpillar, entomophaga aulicae fungus, to proliferate and kill the BTM
Pesticide application is most effective when the BTM caterpillar is small, so now is an ideal time to treat trees. Please be safe, follow all instructions to protect yourself, and only use in a prescribed manner.
If you have BTM caterpillars on your property and you are stuck dealing with them, please be careful to minimize contact with the irritating hairs. Don’t try to clean them up with a leaf blower. Don’t mow on dry days. Don’t stand under or near infected trees on windy days.
If you do get some hairs on you, or feel the telltale itch, immediately wash the affected area with cold soapy water to wash away as many of the hairs as possible. Avoid hot water as that will open your pores for the hairs to enter. Local pharmacies also sell creams to alleviate the symptoms of the rash.
There is a wealth of knowledge regarding the BTM on the Maine Forestry Service website. When you do see outbreaks of moths you can report them to the city, for mapping purposes, through the GoBangor app or through the Service Request page on the City of Bangor Website.
The City of Bangor is not applying pesticides to public properties due to the wide variety of people who use them. While a homeowner can easily determine pesticide sensitivity of those who use their property, this is not something that can be easily determined for public properties across the City. While BTM exposure is unpleasant, we do not want to inadvertently cause an adverse reaction in individuals who are sensitive to pesticides, especially children. Additionally, the City of Bangor will not be applying pesticides to trees on private property.
January 6, 2022:
The City of Bangor has initiated the browntail moth winter operations plan. This includes a survey to determine the extent of the browntail moth infestation on public property, which will be used to guide our winter web clipping efforts. Once the survey is completed the Public Works and Parks & Recreation departments will send out teams to start clipping browntail moth winter webs in parks, roadsides, and other public properties.
Winter web clipping is a very impactful way to limit the spread of the browntail moth. The larvae are very small at this stage, they have not begun to molt, and their webs are tightly woven, which keeps all the caterpillars contained inside. Each web contains up to 400 caterpillars, each having the ability to massively defoliate trees, pupating into moth form, and laying up to 400 more eggs. Each web clipped could potentially prevent up to 160,000 more caterpillars from munching on our trees next year!
Residents can do this same thing to protect their own property. We encourage residents to look at trees on their own land to see if there are winter webs present. The Maine Forest Service (MFS) created a nice video to help you identify the winter webs, clip them, and dispose of them. https://www.youtube.com/watch?v=L6VmwsXE3lg&t=4s [embed?]
If you are unable to remove winter webs yourself and would like assistance, MFS has assembled a list of State of Maine licensed arborists here, https://www.maine.gov/dacf/mfs/forest_health/documents/arborists_prune_btm_webs.pdf
If you would like to speak to a State of Maine licensed pesticide applicator about your browntail moth problem, MFS has assembled a list of companies who are willing to treat for browntail moth here, https://www.maine.gov/dacf/mfs/forest_health/invasive_threats/browntail_moth_pesticide_applicator_info.htm
Maine Forest Service also has a page that helps you identify browntail moth winter webs versus abandoned webs of the fall webworm or eastern tent caterpillar. https://www.maine.gov/dacf/mfs/forest_health/insects/browntail_moth_id_winter_nests.htm
Their browntail moth webpage has a wealth of information and will be a great resource if you want additional information about the browntail moth and other methods of management. https://www.maine.gov/dacf/mfs/forest_health/invasive_threats/browntail_moth_info.htm
Lastly, we also ask that residents report their winter web sightings through the city’s service request page, https://bangormaine.gov/311/request/add . By reporting the location of winter webs under the “Browntail Moth Reporting” type of issue, you will help us track the extent of their spread and aid in future planning. Remember, the city is unable to provide assistance to residents in removing winter webs on private property but the information regarding their location is still helpful.
UPDATE: July 12, 2021
Residents of Bangor have been diligently reporting the caterpillar, at first, and now the adult moths. Our infestation map is starting to come together, you can view that below. Thank you to everyone who has participated in reporting. You can file your own report by clicking here.
Recent rains have done a great job washing toxic Browntail moth hairs into the soil where they are much less likely to cause allergic reactions in residents (unless you are actively digging in the soil). Forecasted rain this week will continue to reduce the negative impact of these hairs. We are seeing the adult moths (pictured below) emerging from cocoons in large numbers and gathering near bright lights at night. The Maine Forest Service is recommending that people do not try to manage Browntail moths in the adult moth stage. However, they do recommend that people turn off unnecessary outside lights between 9:00 pm and 12:00 am (midnight) to avoid attracting them to your property. If they are not being attracted to your property then the chances of them laying eggs is decreased. The good news is that the hairs of the adult moth are not toxic, so they are not contributing to additional outbreaks of rash and itching.
These moths were found in Bangor on July 8.
Unfortunately there is not a lot we (you or the City of Bangor) can do to control this year’s population. The next step, and a very important step, in controlling next year’s population will be the winter nest snipping. These nests are very visible, each nest snipped removes 200-400 caterpillars (and literally billions of toxic hairs) from the 2022 lifecycle, and snipping causes no harm to the tree, to beneficial insects, to wildlife, or to people. As these winter nests appear we will be sharing more information about identification and how you can help prevent the spread on your own property.
Browntail Moth - Home and Garden IPM from Cooperative Extension - University of Maine Cooperative Extension
Browntail Moth Euproctis chrysorrhoea : Forest Health & Monitoring: Bureau of Forestry: Maine DACF
June 4, 2021:
(Photo credit: Maine Department of Agriculture, Conservation & Forestry)
The City of Bangor is experiencing a marked increase in the number of complaints regarding Browntail Moth exposure. This spring, many residents suffered from direct exposure to caterpillar hair and indirect exposure from windblown hairs.
The City has developed a plan to address the increase in Browntail Moth activity that includes a public information campaign, tracking of locations where nests are seen, a clipping program to remove winter nests, and determining the appropriate methods to treat and target impacted foliage.
(Photo credit: Maine Department of Agriculture, Conservation & Forestry)
The browntail moth is an invasive species normally found on the coast of Maine and Cape Cod, but in 2021 the winter webs were discovered in all 16 Maine counties. This moth is an insect of both forest and human health concern.
Caterpillars are active from April to late June. Hairs remain toxic throughout the summer but get washed into the soil and are less of a problem over time.
The browntail moth caterpillar has tiny poisonous hairs that cause dermatitis similar to poison ivy on sensitive individuals. People may develop dermatitis from direct contact with the caterpillar or indirectly from contact with airborne hairs.
The hairs become airborne from either being dislodged from the living or dead caterpillar or they come from cast skins with the caterpillar molts. Most people affected by the hairs develop a localized rash that will last for a few hours up to
several days but on some sensitive individuals the rash can be severe and last for several weeks. The rash results from both a chemical reaction to a toxin in the hairs and a physical irritation as the barbed hairs become embedded in the skin.
What are the symptoms of browntail moth toxin exposure?
A skin rash on any part of your body that was exposed. The rash tends to be red, bumpy, and itchy.
Respiratory issues such as breathing difficulty can occur if the browntail moth hairs are inhaled.
If you are having trouble breathing, swallowing, or swelling of your mouth, tongue, or throat, call 9-1-1.
How do I treat the rash?
According to the Maine CDC, mild rashes can be treated at home with:
A cool bath with baking soda or Aveeno Oatmeal Bath
Hydrocortisone cream, such as Cortaid, applied sparingly to the itchiest areas
Calamine or caladryl lotion
If home remedies are not working, see your healthcare provider. There are medications that your healthcare provider might recommend.
Be careful not to apply any creams or lotions to places where young children may rub them into their eyes or mouth.
Is the rash contagious?
You cannot "catch" the rash from another person like you can a cold. The hairs need to come in contact with your skin, mouth, throat, or respiratory tract for symptoms to appear.
As part of the City's informational campaign, signage like this will be placed in City parks and other public properties:
Learn more about the Browntail Moth by visiting the Maine Department of Agriculture, Conservation & Forestry's website.
Maine CDC Browntail Moth fact sheet