RISCC | Rhode Island State Conservation Committee



Eastern Rhode Island Conservation Committee
Moth infestation brings a crowd to hear expert talk
(Newport Daily News)

April 25, 2016  |  Marcia Pobzeznik


TIVERTON — Prudence Island has been hit hard; so have Tiverton, Little Compton and Bristol, but the problem of winter moths deforesting areas will probably get worse before it gets better.

 That’s because the only fly known to impact the moth larvae takes years to establish itself in numbers great enough to make a difference.

So many people are affected by the beige-colored moths that start fluttering around in November and December that it was a standing-room-only crowd Wednesday night at Sandywoods Farm to hear Heather Faubert, a professor of entomology at the University of Rhode Island, talk about the moth and ways to try to combat it.

Faubert works with fruit farmers and started studying the moth in 2005 after the larvae started affecting fruit trees.

Sharon Culberson of Tiverton said she lost 18 blueberry bushes she had for 25 years.

“I haven’t had a blueberry in two years,” she said.

That’s because the moth larvae, or caterpillars that hatch in the bark of trees in the spring, climb into the flowers on apple trees and blueberry bushes, and buds on deciduous trees, and eat them from the inside, said Faubert.

They like all sorts of trees.

The bark of the trees is where the female moths, which do not fly, mate with the winged males in late fall and lay their eggs. Each female can lay between 100 and 300 eggs — thus the population explosion here over the past few years.

The winter moth, a European native, was first seen in Prince Edward Island, Canada, in the 1930s and slowly made its way to Massachusetts in the 1990s, then to Rhode Island and Connecticut in the 2000s.

“In 2004 we started to see it in Bristol and Warwick, and it’s been spreading since then,” Faubert said.

It is so hard to see the eggs — which are orange when they are laid but turn blue about two days before they hatch — that Faubert now has an email blast to alert people to hatching so they can spray the young larvae and greatly reduce the damage to canopies and fruit trees.

The larvae have hatched between late March and mid-April the past few years, and all hatch within eight days, she said. They eat themselves plump within two weeks and then drop onto the soil, where they dig down and pupate until November or December. Then they emerge and start the cycle over again.

“Last May, they totally defoliated our whole property,” said Corrie Marchand of Tiverton. “We had no leaves,” she said of her 1-acre lot.

Most of the trees had a second growth by July, she said, but another year of the onslaught could spell doom.

“It’s really scary to think about the damage they’re doing,” said Marchand, who plans to hire a landscaping company to spray this year before the larvae can do too much harm. “I don’t know how long the trees can survive the beating they’re getting.”

Cecil Leonard of Tiverton said he lost “a big, beautiful oak” to the moth larvae. “They’re pesky little buggers. We’ve got to figure out how to get rid of them.”

“Come to Prudence Island. It’s bad. We’re losing all our shade,” a woman said from the crowd.

Bristol Conservation Commission member Raymond Payson, who manages the town’s street-tree planting program, said there are areas of town that were “heavily hit” the past few years.

“It’s hard to predict where the outbreaks are going to be. It hits and misses. It’s sort of like a tornado. It goes after trees that leaf out early,” Payson said. If the larvae don’t have a readily available food source on the tree they hatch on in the spring, they send out a silken thread and “balloon” to other areas, Faubert said.

So many larvae are feeding during the few weeks between hatching and dropping to the ground that their droppings “sound like rain,” Faubert said. Marchand said her bushes were covered in the caterpillars’ silken threads last spring. The best time to kill the larvae is when they are very young, soon after they hatch and before they can crawl into the buds, Faubert said. She recommended products such as DiPel, Thuricide and Biobit. “Once they’re in the buds, there’s no getting at them,” she said.

Wrapping trees in the fall, before the females begin to climb up from the ground, can keep them from climbing too high and can concentrate the eggs. The eggs can be sprayed with a 3 percent horticultural oil solution to suffocate them, but the eggs are so tiny they are extremely difficult to see in trees with bumpy bark, she said.

The best bet so far seems to be the fly, called Cyzenis albicans. It has controlled the moth population in Prince Edward Island since being released in the 1950s. It lays its eggs on the leaves the larvae like to eat, so the larvae end up eating the fly eggs, which then hatch inside the moth caterpillar and eat it alive, said Faubert.

“Ewwww,” said the crowd.

There have been releases of the flies at 40 sites in the Northeast over the past few decades.

The flies were first released in Rhode Island in 2011, and have now been released at seven sites around the state. Last year, flies were released in Little Compton. They have also been released in nearby Westport, Mass.

The populations will spread out naturally, but it will take time to increase to the numbers needed to combat the winter moth population, Faubert said. “It’s a great solution,” she said, “but it takes time.”

Faubert’s talk was organized by the Eastern Rhode Island Conservation District, whose trustees suggested a public workshop on winter moths was timely, said Sara Churgin, its new district manager.

 An estimated 100 or more people turned out for the talk on Wednesday night.

“I never anticipated such a turnout,” Churgin said, “so clearly I don’t have a winter moth problem.” She lives in Portsmouth.

To sign up for the email blast about hatching, send an email towww.hhf@uri.edu

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