Winter moths invaded Maine in 2012. They do a lot of damage to trees, particularly hardwoods like oaks and maples.
They have no natural predators here, so biologists are bringing one in. It's a parasitic fly which they say will eat only winter moths.
"These flies, once they’re mated, will be attracted to the scent of leaves that have been chewed on by the winter moths," said Colleen Teerling of the Department of Agriculture, Conservation and Forestry. "They’ll go fly to those trees and lay their eggs on the leaves."
The winter moth caterpillars will come along and eat those eggs.
The eggs will develop into larvae inside the moths eventually, devouring them from the inside.
It sounds gruesome.
"As a biologist, I find this pretty cool," says Teerling. "It’s sort of parasitism. Other people may find it kind of disgusting, kind of like the monster breaking out of the prison in 'Alien.'"
This system is working in other places say the scientists who prefer it to spraying.