North Stonington — Elaine Robarge has taken her leaf blower out earlier than she expected this year, using it to clear her deck and furniture of a thin dusting of black insect droppings and leaf fragments two or three times a day.

And each morning, she said, it looks as if she did nothing.

The daily nuisance, which began about three weeks ago, is the work of the gypsy moth — an invasive species that attacks the leaves of deciduous trees such as oaks.

Robarge's home is set a short way into the dense forests along Denison Hill Road, surrounded by 50-foot-tall oak trees.

Her neighbor, Sonya Barrs, who lives farther down the road, said her family can't use their hot tub because every time they open the cover, droppings fall in.

It's gotten so bad, said Robarge, that she can hear debris fall whenever a light breeze comes through, and a few times she's gone straight from cleaning the deck to the shower.

She rarely goes into her backyard these days without something to cover her head.

"This is gross, they give me the creeps," she said of the caterpillars. "It's like a sci-fi movie."

For John Rudak, who also lives in the Clarks Falls section of town, horror is the more applicable genre.

His house was covered with the caterpillars "in a matter of a few days," he said.

"I don't know if it's my imagination, but my oak trees are just not looking healthy," Rudak said.

The last major outbreak of gypsy moths was in 2005 and 2006, which saw 200,000 acres defoliated across the state.

But that paled in comparison to the 1981 outbreak, in which 1.5 million acres were defoliated.

Robarge remembers the exterior walls of her home covered in caterpillars.

It was so bad, the town hired an aerial sprayer to kill them, Treasurer Robin Roohr said.

It's difficult to say what triggers outbreaks, which occur about every 10 years or so, said Kirby Stafford, head of the Department of Entomology at the Connecticut Agricultural Experiment Station.

Following the outbreak in the 1980s, the mold Entomophaga maimaiga has played an important role in managing the gypsy moth population.

Introduced from Japan, the mold only interacts with the gypsy moth family.

It consumes the caterpillars and bursts into spores that spread to other caterpillars, an effect that was first described by scientists at the Connecticut Agricultural Station.

The mold is limited by low rainfall, however, which causes it to be less active, and dry springs in both 2015 and 2016 may be the culprit for the current moth outbreak, Stafford said.

In June 2015, after reports of large gypsy moth populations in New Haven, Middlesex as well as parts of Hartford and New London counties, DEEP declared it an outbreak.

While one year of defoliation can be tolerated by trees, consecutive years of defoliation combined with other stressors, such as drought, are more damaging, Stafford said.

Most of the time, the caterpillars feed during the day.

However, during "outbreak conditions," they may feed continuously — which Robarge suspects may be the case, considering how many times she cleans her deck.

"I'm concerned they're going to start eating my vegetables and flowers," she said.

This year most of the calls that Stafford's office has received were from eastern and coastal towns.

Generally, he said, towns south of Route 1 mostly were affected by another species, the winter moth, while towns north of Interstate 95 have seen the damaging effects of the gypsy moth.

The best time to spray for such insects largely has passed, as chemical agents are most effective before the caterpillars have matured.

"The decision to treat would be largely the decision of the homeowner or municipality. There hasn't been a state program since the 1980s," Stafford said.

A fact sheet issued by the state last year notes that there are a number of piecemeal measures homeowners can take, including a couple of chemical agents, but their effectiveness may be limited.

Individual trees can be aided by creating a barrier with a burlap sack and twine to trap the caterpillars as they travel up and down the tree trunk.

Barrs said her family has taken to washing the caterpillars off their house and spraying their young ornamental trees, such as a 3-year-old weeping cherry, but they're still worried.

While the chore is frustrating, Robarge is more worried about the effect years of consecutive defoliation could have on her towering oak trees.

"Never mind the mess, it just ruins our trees," she said.

n.lynch@theday.com