The invasive moths are native to Europe and first appeared in New England around 2004. The females lay their eggs between Thanksgiving and the New Year, and their offspring can cause extensive damage to foliage when they hatch as caterpillars in the spring.
Heather Faubert, a research associate at the University of Rhode Island, said so far there’s only one real way to deal with winter months.
“We've released a parasitic fly in conjunction with people from the University of Massachusetts,” said Faubert. “And so, this is a fly that parasitizes the winter moth caterpillars and so our hope is that over many years that the fly population will build up and bring winter moths numbers down to manageable levels.”
The winter moth caterpillars will eat the parasitic fly eggs while munching on leaves, and the eggs eventually develop inside the caterpillars.
In the meantime, Faubert said there’s not much people can do from their homes. The males are the ones you see flying around, but the females are the main worry.
“It’s the females laying the eggs and the females are kind of hard to find,” said Faubert. “They don't have wings and they don't fly, they just climb around tree trunks and tree branches.”
Faubert said last spring’s sporadic shifts between warmer and colder temperatures may have played a role in limiting the damage from winter moths by causing offspring to hatch too early, but the invasive species has the potential to cause widespread defoliation next year.