School officials in Freeport have decided to treat browntail moth nests at athletic fields with an organic pesticide rather than a synthetic one, in response to parents’ concerns about the environmental effects of the chemical spray.

Dennis Ouellette, director of facilities and transportation for Regional School Unit 5, discovered what he described as “a pretty bad infestation” of browntail moths in oak trees near fields at Mast Landing School, Morse Street School, Freeport Middle School and Freeport High School. The district hired Whitney Tree Service, a licensed pesticide applicator in Maine, to spray the nests with a product called Conserve SC. Ouellette sent an email to parents to inform them spraying would take place at 5 a.m. on Saturday and advising them to avoid the fields for at least 24 hours. No trees near RSU 5 schools in Pownal and Durham need to be treated.

“As you may know, (browntail) moths can cause a serious rash for some individuals and possible respiratory issues when the caterpillars begin the molting process,” Ouellette wrote in his email. “Due to the large number of webs on our property, we feel it would be beneficial to target spray trees harboring nests in order to head off the molting phase of this insect.”

Superintendent Becky Foley said some parents reached out to thank Ouellette because they were worried about the way the infestation would affect their children. Others expressed concern about the use of a synthetic pesticide, which could be harmful to other insects and aquatic life. Since then, the district and Whitney Tree Service have decided to use an organic product called Entrust SC, which has been listed by the Organic Materials Review Institute.

“It was because of these concerns that we did more research and switched products,” Foley said Tuesday.

Browntail moths nest at the tops of oak and fruit trees. When the 2-inch-long caterpillars leave the nests in May, they feed on new leaves and can cause extensive damage to trees. They are covered with toxic hairs that drift through the air, which can cause a rash similar to poison ivy or respiratory problems. By June, the caterpillars will spin cocoons and eventually become moths, but their hairs can linger in the environment for months.

The moths are usually found only in coastal southern Maine and on Cape Cod, but inland infestations are possible. The population has surged in Maine since 2015, in particular in Sagadahoc County. The Maine Forest Service said aerial surveys last fall showed more than 62,600 acres of woodland defoliated by moth larvae, compared to 11,000 acres damaged in 2015. A pharmacy in Brunswick reported at least 40 requests a day last June for rash treatment, and the town of Cumberland also used an insecticide to kill the caterpillars last spring.

Last year in Freeport, Wolfe’s Neck Woods State Park put up warning signs about the caterpillars, and the town treated infested sections of Winslow Park, a public campground. Ouellette said the district didn’t treat any of its properties last year, but employees and students have contracted the rash in the past.

“My groundskeepers, they tend to get rashes,” Ouellette said.

Whitney Tree Service did not return a call for comment Tuesday. Ouellette and Foley said they expect the organic product to be just as effective as the synthetic one. The organic treatment is usually more expensive than the synthetic treatment, but Ouellette said Whitney Tree Service agreed to spray the trees for the price already agreed upon – $3,410. The treatment typically targets trees with nests, and Foley said Entrust is not toxic to humans and most insects. The end of May is typically the last opportunity for the treatment to be effective, so the treatment will take place as originally scheduled.

Among the locals who had expressed concern was Caitlin Shetterly, a Freeport resident who wrote a book called “Modified: GMOs and the Threat to Our Food, Our Land, Our Future.” In an email to the school board Monday, Shetterly said she worried about a synthetic pesticide drifting and negatively affecting the town’s environment and residents.

“I think this plan should be halted and brought to a town-wide discussion before you go forward,” she wrote. “Though it will only take place on the school grounds, it will affect many of us humans who live close to the schools, and countless creatures that live in the trees, grasses and waterways that are near and around the schools.”

If possible, she would have preferred the spraying to be canceled. Whitney Tree Service will work early in the morning before bees are very active, but Shetterly said even the organic alternative could be harmful to bees before it dries. However, she said Tuesday the switch in product was a step in the right direction.

“That means that people were heard,” Shetterly said. “The school is between a rock and a hard place. They’ve gotten some push-back, and they’re trying to make everyone happy.”

Shetterly credited Ouellette and the school officials with listening to concerns she and other parents raised. In the future, she hopes the town as a whole will discuss its policies on the use of these chemicals. While Town Manager Peter Joseph said town policy favors organic products, no local ordinance restricts the use of pesticides in Freeport.

“Now more than ever in the history of the planet, we need to evaluate these decisions carefully,” Shetterly said.

Megan Doyle can be contacted at 791-6327 or at:

[email protected]

Twitter: megan_e_doyle