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Concord has mostly dodged the bullet from this moth infestation

  • A Lymantria dispar caterpillar crawls along partially eaten leaves of a tree in Trenton, N.J. in 2017. AP file

  • In this June 1, 2016 photo, a gypsy moth caterpillar crawls on a leaf in Plainfield, Conn. Last year's dry spring, coupled with the recent stretch of dry weather, is being blamed for the resurgence of the caterpillar across parts of southern New England. Scientists said this year's crop is one of the largest since the 80s. (Aaron Flaum/ via AP) Aaron Flaum

  • A female Lymantria dispar moth lays her eggs on a tree. Bob Child / AP file

Monitor staff
Published: 7/23/2021 4:25:08 PM

The Concord area has largely avoided this year’s outbreak of gypsy moth caterpillars and will never have to face one in the future, although that’s only because the insect is being renamed.

“We’re seeing as much in the greater Concord area as up north, just small pockets here and there,” said Jen Weimer, a forest health specialist with the New Hampshire Division of Forest and Lands. “I would say we’re at the peak right now. The caterpillars are starting to pupate or die off, so whatever you’ve got for defoliation right now I would say that’s it.”

New England natives remember past gypsy moth outbreaks in the 1980s and 1990s, when voracious caterpillars stripped millions of acres of trees of their leaves from Connecticut to Maine. But the damage has been minimal for more than a decade partly because a fungus, Entomophaga maimaiga, has proved to be an effective biocontrol.

But fungi like wet conditions and the region’s dry weather over the past 14 months – until this month, at least – has reduced its presence. In response, the population of gypsy moths has exploded.

Surveyors with the New Hampshire Division of Forests and Lands have found widespread defoliation attributed to a population boom of various moth caterpillars. Kyle Lombard, the coordinator of the division’s forest health program, said that the department has surveyed 20% of the state and found 30,000 acres of defoliation, the worst since 1992.

Fortunately for leaf-peepers, the affected trees are primarily red and black oaks, not maples or other trees whose leaves turn in the autumn.

Vermont and portions of Maine have been particularly hard hit, while New Hampshire’s biggest outbreak has been around North Conway, said Weimer.

“We’re starting to see some re-leafage –  a second set of leaves growing on some – so we should hopefully recover a little bit,” she said.

Defoliation can damage the production of fruit trees but rarely a single season of such caterpillar attack rarely kills, although that can weaken them, making them more susceptible to other insects or diseases.

The division is still doing surveys to determine the extent of the damage.

As for the name “gypsy moth,” the Entomological Society of America has decided to stop using it, as well as “gypsy ant” for a species of ant, because “gypsy” is considered a derogatory way to refer to the Romani people of central Europe. For the time being the society will refer to the species by its scientific name,  Lymantria dispar, although another common name may be adopted.

(David Brooks can be reached at 369-3313 or or on Twitter @GraniteGeek.)
David Brooks bio photo

David Brooks is a reporter and the writer of the sci/tech column Granite Geek and blog, as well as moderator of the monthly Science Cafe Concord events. After obtaining a bachelor’s degree in mathematics he became a newspaperman, working in Virginia and Tennessee before spending 28 years at the Nashua Telegraph . He joined the Monitor in 2015.

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