They are everywhere. You can see them swarming up your trees, floating above the roads and flying into your homes when you leave the door open for just a few seconds. Recently, I traveled to Massachusetts for Thanksgiving, and upon my return home to Harpswell, thousands of them were covering the exterior of my house. The winter moth infestation in Maine has gone too far and residents need to take action.
Earlier this week, Cape Elizabeth made the interesting decision to stop banding their trees and subsequently take an observational year to determine the effects of parasitoid flies, which since 2013, have been released in municipalities throughout the state to control winter moth populations. While this decision may make sense for the Cape Elizabeth town community, I urge residents across the state not to use this as a guide.
Aside from the fact that they swarm any light source emitted and make their way inside our homes, these moths are an invasive species, originating from Europe. They first appeared in New England back in 2003, and have thrived in their new environment in Maine due to a lack of native predators. For that reason, they are abundant.
The winter moth’s rampant reproduction have led to the decimation of leaves on many deciduous trees and shrubs in Maine. From June to November, the larvae burrow themselves underground and form cocoons beneath the soil. The moths activate in the November through January months– on days above freezing– when they crawl up the trees and deposit their eggs in host tree bark crevices, scales or loose lichen. Come springtime, these eggs hatch and caterpillars begin feasting on the leaves of these trees. This begins the process of defoliation, which trees cannot survive year-in-and year-out.
This brings me back to why I am a bit skeptical of Cape Elizabeth’s decision to sit back and “observe” for a year. Personally, I believe that any number of winter moths is too many and can have negative effects on our environment, so I figure there is no reason not to take the initiative and band as many trees as possible
Tom Schmeelk, a forest entomologist with the Maine Forest Service, stated: “This week I have received reports of high moth numbers in South Bristol, Boothbay Harbor, West Bath, and now Harpswell.” Furthermore, he added that “Winter moths tend to pop up as outbreaks in certain spots, likely where the biocontrol has not gotten to yet or hasn’t built significant numbers.”
This is likely the case in Harpswell, and these other coastal communities that have experienced moth outbreaks in recent weeks. The evidence makes it clear that in these communities, releasing parasitoid flies alone is not enough. Yes, it’s a good first step, but the fact of the matter is that these moths are still too abundant. Even if populations are somewhat dwindling in areas, they are still far higher than they should be.
In addition, the winter season in Maine is only getting warmer. A recent study conducted by the University of Massachusetts in Amherst suggests that average winter temperature will increase by five degrees in the next 50-to-60 years, leaving more days for winter moths to make their way up Maine trees and deposit their eggs. We must attack the problem now before it can get worse in the future.
In Harpswell, every tree band I have noticed has been filled with moths looking to reproduce and create caterpillars that will kill our trees, showing just how effective they can be and how necessary they are. Schmeelk mentions that “banding is effective at low or medium population densities” while “high densities often require multiple bands to prevent the female moths from walking over the saturated bands.”
In many Maine communities, leaving winter moth control solely up to the parasitoid flies is a dangerous idea. We must take all measures possible to limit their reproductions. I urge residents not to follow in the footsteps of Cape Elizabeth. We can all make the simple “observation” ourselves: There are too many moths. Please consider banding your trees- multiple times over if necessary- especially older trees that won’t make it through many more seasons of defoliation. If we all do our part, we can greatly reduce the number of moths that pester us each winter, and hopefully reduce the detrimental environmental effects in the process.
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