Field Notes

Defoliation can be seen from the Wesley Chapel area near Dunmore. Dave Curry photos
Defoliation can be seen from the Wesley Chapel area near Dunmore. Dave Curry photos

The summer solstice has come and gone, and already days are slowly beginning to get shorter. We are starting the long, slow descent through the dog days of summer into the pleasant, mellow days of fall followed by the cold, bitter, short days of winter.
But if you lived on Michael Mountain just north of the high school, you might think that winter has arrived early.
In vast areas, many trees have been stripped of their leaves by an insidious invader leaving the forest in a distinctly winter-like state.
That invader and trouble maker is the gypsy moth and they have a hardy appetite for tree leaves. Oak leaves are like filet mignon to this lepidopteran, but when the oaks are gone they will eat almost anything green, including maple, apple, beech or anything else they can find. They even will eat some pine and rhododendron in a pinch.
The GM was introduced into New England from Europe in 1869 by a scientist hoping to cross them with silk worm moths. That Frankenstein moth didn’t pan out, but somehow the gypsy moth got loose. Since then, they have been growing and advancing at the rate of about 10 miles per year. The first wave passed through the county about 20 years ago and was mostly unnoticed then. But like pop-up thundershowers, they can show up anywhere now.
Mike Holstine, who lives on Michael Mountain said his first indication of the invader came while he was sitting on his porch.
“I thought a light rain was falling from the sounds I was hearing,” Holstine said. “But then the caterpillars began to show and the noise came from them munching on leaves and their droppings falling to the ground.”
After a few days of that, most of the leaves were shredded off of the trees and “it looked just like winter.”
The gypsy moth hatches in early May, climbs into the timber and suspends themselves on spider-like threads. Then the wind will scatter them in all directions. Some may be carried long distances but if they fall into good habitat with lots of oak, they will go to work and do some damage. Currently much of the oak timber on the east side of Michael Mountain has been defoliated. Also east of Rt. 92 and north of Frost, quite a bit of defoliation can be seen from the highway. Other areas may also be affected, so the West Virginia Department of Agriculture as well as the US Forest Service will probably be doing aerial assessments.
Some suppression spraying was done earlier in May on the west side of Michael Mountain in Seneca State Forest by the Department of Agriculture. And some birds, mice and bats could also impact the moth populations to a minor degree.
Does this harm the trees?
Yes. It certainly can. If defoliation occurs two years in a row, many trees will die. Trees that are already stressed by drought or other insect damage may also die after one defoliation.
So, that is the bad news. But is there any good news?
Yes. Most of the defoliated trees will grow new leaves by mid-July. The acorn crop will certainly be affected as will other fruit and nuts. If there is no defoliation next year, the forest should return to normal in a year or two.
And there is more good news. While driving across the Hill Country Road, I stopped to look at some light defoliation and found a crashing population of gypsy moth. Large numbers of two-inch, black caterpillars with pairs of red and blue spots were hanging lifeless, some hanging straight and some hanging in V-shapes. In large populations an extremely contagious virus takes over like the ”Flu” in a Stephen King novel and can wipe out upwards of 95 percent of the caterpillars. Most will never make it to the next stage of their life which is pupation – a two-to-three week resting period before they become adults.
Lighter populations will not be affected by this virus and will go on to hatch, grow and defoliate next year.
So, if you suspect that you have gypsy moth or have susceptible trees that you care for, here are some things that you can do.
GM larvae and pupae are always looking for a place to hide. Provide a place for them by tacking up skirts of burlap or canvas around your favored trees.
Larvae will accumulate there and you can destroy them by hand by dropping them into a cup of soapy water. Pupae, finger-sized black shells of the resting stage, will also be there and can be destroyed. And if all that fails and they make it to adulthood, the egg masses – thumb-sized tan spongy masses –will be close by and can also be destroyed by hand. The huge white females cannot fly, so adults will not go far before laying their egg masses.
Dave is a telescope operator at the Green Bank Observatory and can be contacted at davecurry51@

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