Timberland owners and state officials hope to capitalize on a successful pesticide campaign against a spruce budworm outbreak by resuming aerial treatment next spring.
Targeted aerial spraying across 240,000 acres in Aroostook County this spring helped bring the native pests under control and prevent a population surge that could threaten Maine’s forest health and economy.
Stakeholders plan to spray again this year. But some pockets of elevated budworm populations in Northern Maine are on land owned by small woodlot owners who declined to join a program funded by the state and federal governments.
“In an ideal scenario, you’d be able to treat across the landscape,” said Maine Forest Entomologist Allison Kanoti said.
Across the border in New Brunswick, authorities have been managing a spruce budworm outbreak for about a decade. That pesticide program has kept populations below the threshold of an eruption despite migration of budworm from an massive ongoing outbreak in nearby Quebec.
The same scenario could play out in Maine, according to Kanoti.
“We don’t expect it to lead to failure of the program,” Kanoti said.
“We expect that the strategy will still work, its just that we expect there will be more local spread from the spots that will have to continue to be reacted to in order to prevent the broader spread of the outbreak,” she added.
Samples taken from areas treated this year show that spraying specialized pesticides on budworm larvae was overwhelmingly successful.
Places that had 90 budworms per branch of spruce or fir last year have just three or four now, said Neil Thompson, a forestry professor and budworm specialist at the University of Maine Fort Kent.
“It’s beyond expectation, it’s at the upper end of hope,” Thompson said.
The campaign’s objective is to prevent the repeat of a legendary budworm outbreak in the 1970s and 1980s that damaged millions of acres of Maine forest and reshaped the forestry industry and state clear cutting regulations.
But it is not supposed to eradicate budworms, Thompson said. The native pest goes through periodic population explosions, but is typically kept within healthy limits by predators and parasites. Targeted applications of specialized pesticides like tebufenozide, which the federal government classifies as “practically nontoxic” to mammals and birds, help mimic those conditions.
Thompson said some areas in hotspots weren’t sprayed last year because they were buffer zones around wetlands, rivers, or other sensitive environmental areas.
But the elevated populations that remained in those buffers were targeted by native predators such as parasitic wasps, according to Thompson.
“I call them the cleanup crew,” Thompson added. “They did some heavy work on what was left of that population after treatment and in the untreatable area, so I was thrilled to see that.”
A coalition of large land companies plan to resume treatment again in 2026, but on a much smaller area, said Alex Ingraham, president of Pingree Associates, one of Maine’s biggest forest owners.
“We estimate currently that it’s going to be a 50,000 to 60,000 acre treatment block and that includes small landowners,” Ingraham said.
The effort was assisted by $600,000 in federal funding to expand the work of the spruce budworm lab at the University of Maine which expanded its sample testing ability.
Congress has also set aside $10 million in a federal agriculture bill to fund the effort, according to Ingraham. Added to that about $3.7 million from a state appropriation and funding left over from last year.
Some small landowners within the outbreak areas declined to sign on to the program next year, said Kanoti, the forest entomologist.
Fifty woodlot owners have expressed interest in participating, totaling about 3,500 acres, Kanoti said.
Those owners were excluded from the first year of the program because of incomplete data and information on wetlands, streams and other sensitive areas on their property, she added.
The Maine Forest Service sent out about 140 notices to nearby landowners to join the campaign but less than a quarter responded, according to Kanoti.
Some may be uncomfortable with aerial spraying while others decided to harvest their tree stands rather than treat them, she said.
Even though there is less interest than expected, Kanoti expects the overall effort should be successful.
“In some ways it’s OK to have this smaller program this year,” Kanoti said.
“My hope would be that if there is funding available in the future we would have larger awareness and larger interest in the program.”
This story appears through a media partnership with Maine Public.
