winter moth 2020

A winter moth rests outside a kitchen window Saturday evening in South Portland on the Cape Elizabeth line. Kelley Bouchard/Staff Writer

CAPE ELIZABETH — Officials in Cape Elizabeth have decided not to take drastic measures such as banding trees on town property this year to guard against Operophtera brumata – better known as the winter moth.

According to Cape Elizabeth Tree Warden Todd Robbins, ongoing efforts, including the introduction of a parasitoid fly, may keep populations of the invasive moth down.’

Robbins said he is prepared to resume banding after this year if other measures fail.

According to the state department of Agriculture, Conservation and Forestry, the winter moth was introduced to North America from its native Europe in the early 20th century, having been recorded in Nova Scotia in 1930. By the early 2000s, the moth had been spotted in Massachusetts and has been moving north ever since, according to the department’s website.

Robbins said he’s been fighting the winter moth locally for at least five years, including spraying tree bark with oils to kill off moth larvae and wrapping tree trunks in sticky plastic to kill the female winter moth.

But in recent years, Robbins said, there appears to have been a decline in populations, though by his own admission Robbins said he not a scientist and does not have official data to prove this. Instead, he said, he’s basing his opinion on his own observations, and the observations of concerned citizens who have been reporting on moth activity and damage to trees over the years.

“Here in Cape, it seems that we’ve had less of it,” he said.

The damage is the most visible sign of the problem. Robbins said the moth larvae emerge in the spring, eating leaves, buds and flowers.

“They eat everything,” he said.

Tom Schmeelk, a forest entomologist with the state department of agriculture, conservation and forestry, said the moths typically eat oak, maple and cherry trees. The damage alone isn’t usually fatal to the tree, he said, but it can make the tree more vulnerable to other stressors such as drought or the more common gypsy moth.

Like Robbins, Schmeelk said hard data doesn’t provide a clear picture of the infestation, but state officials have received reports of damage or moth activity as far north as Bar Harbor. According to data provided by Schmeelk, state officials received more than 2,000 responses in 2017 alone to a statewide survey asking the public to report moth sightings or damage. Reports such as these, Schmeelk said, provoked the state to act.

Starting in 2013, officials began releasing parasitoid flies, which lay eggs that kill winter moth larvae, and have been effective in controlling winter moth populations in Asia. Shmeelk said state officials started in Kittery, and have been working their way up through coastal communities, including releases in Cape Elizabeth at Two Lights State Park in 2015 and at a private residence in South Portland in 2017. Schmeelk said the state has also released the flies as far north as Bath and Harpswell, and there are plans to do the next release in Boothbay Harbor.

Schmeelk said state officials have gone back to the release sites to collect winter moth larvae to test for parasites, and just as Robbins saw in Cape Elizabeth, officials are noticing the damage and moth activity appears to have lessened, which is a sign that efforts to control them are working.

“There’s still damage there,” he said. “There’s still winter moths, but it’s nothing like it was before we released the parasitoid fly,” he said.

Robbins agreed that the winter moth would never fully go away, but the hope is that the populations are controlled enough that they won’t be devastating local trees anymore. In addition to Robbins, The Cape Elizabeth Land Trust has announced on its website that it is also not going to band trees on trust-owned land, following Robbins’ example, but neither Robbins nor the trust is advising private landowners what to do on their own land. Robbins said landowners have make their own decisions based on what they are observing about moth activity and tree damage.

“I’m leaving that up to their discretion,” Robbins said.

Sean Murphy 780-9094

Email: [email protected]

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