Aliens and body snatchers

The invasive brown-tail moth was introduced into New England in the late 1800s and in recent years has begun to spread into new areas throughout Maine. The caterpillar can cause serious harm to trees, however, it’s the toxic hair they possess, which causes painful poison ivy-like rashes on those who come in contact with it, that is the utmost concern for communities affected by brown-tail infestations. UMaine entomologist Eleanor Groden and her research team are working in collaboration with the Maine Forest Service and affected communities in the state to identify the natural enemies of the invasive species, which may be used to help curb the rapidly expanding brown-tail population.


Eleanor Groden:
This is a caterpillar that is in the position to start pupating right there.

The brown-tail moth was introduced sometime in the late 1800s. It very rapidly spread throughout New England. The infestation extended all the way up to Nova Scotia and down to Long Island.

By the early 1920s, the population started to retract to a few islands in Casco Bay and the very tip of Cape Cod and nowhere else in the Northeast.

We saw a much bigger spread throughout the coastal areas of Maine to the point where in 2005, we had about 24 to 25,000 acres that were defoliated. Then by last fall, we saw that the defoliation had increased to about 64,000 acres.

We’re seeing an expansion of this insect that we haven’t seen in over a 100 years.

It is a serious concern for communities that are infested, not only because these insects feed on a number of different deciduous trees. They do cause severe defoliation and can cause mortality of these trees.

What is of utmost concern to communities and homeowners is that they possess what are called urticating hairs that contain a toxin that when you come in contact with these hairs it can cause a severe rash. In heavily infested areas where you have large numbers of caterpillars, these hairs are in the air.

They settle on the ground, but if someone is raking, mowing their lawn, playing in the leaf litter it brings them up in the air and you can have respiratory problems that result from it, as well.

Karla Boyd:
There’s so many overwintering nests.

We’ll collect caterpillars and puparium and the egg masses. A lot of the time, we’ll bring that back into the lab. We’ll have a bunch of rearing experiments going on. We’ll try to rear those out to a certain point, and then we run experiments where we expose them to different enemies.

The one that we’re focusing on right now are the parasites. The parasitoids of brown-tail include a couple of different wasp species and some fly species.

The parasites go into the caterpillar, eat them from the inside out, and then help us control their populations.

Eleanor Groden:
We’re looking at management strategies that will work with these rather than interfere with their activities.

Karla Boyd:
We’re looking mostly around south central coastal Maine. Our epicenter, I guess you could say, is Bowdoinham, Maine.

Kate Cutko:
We are told that Bowdoinham, particularly this stretch between Bowdoinham and Topsham, was the hardest hit, that we were pretty much the epicenter last summer.

Eleanor Groden:
This one could die, or it could also emerge as an adult. There are a number of communities that we’re working with in the affected area. There have been very proactive citizen groups to work with trying to help manage this infestation.

Kate Cutko:
We’re also practical folks here. We wanted to tell people what they could do today to make their lives better in the face of this infestation. We, the library, went ahead and purchased a 16-foot pole pruner that could be borrowed by library patrons, and taken so that they could make a difference for that one tree.

If they had a small orchard, they could conceivably clear it, and those would be healthier trees when the caterpillars were due to hatch out.

Kate Cutko:
They’ll die because you are going to squish it right now.

Eleanor Groden:

It’s very important to me to be working on a project that is of high significance to the local community here in Maine.

Kate Cutko:
We are lucky enough to have University of Maine scientists feeding us that latest information. It’s a great collaboration.

Karla Boyd:
Anything to help the community and to control this pest species is what I want to do.