Army Worms Invade Chappy
By JULIA WELLS
The people of Chappaquiddick may have declared an uneasy truce in their recent war of words over whether to enact a district of critical planning concern, but this week there was an army on the move on the small island at the extreme eastern end of Edgartown - and it had nothing to do with building moratoriums or long-range planning.
It was an army of worms - in fact an army of army worms - and at Pimpneymouse Farm they had just finished plundering a large hayfield on the southwest corner of the farm. The dirt driveway that runs into the farm was a writhing, seething mass of thousands of gray-black worms in a scene that was a little like something out of a science fiction movie.
Maybe more than a little.
"They are moving. They're climbing up the stalks of the alfalfa now and they are munching away," said farm owner Edith W. Potter.
Huge infestations of army worms have recently been reported in other locations in Massachusetts, including the south shore of Cape Cod, but Mrs. Potter's report yesterday was the first on the Vineyard.
By late yesterday afternoon a second report had come in. James Athearn, the owner of Morning Glory Farm in Edgartown, was on his way to inspect one of his fields in West Tisbury where army worms had been seen. Mr. Athearn had received a call from his uncle, Leonard Athearn, who had spotted the worms.
Horticulture and entomology experts at the University of Massachusetts say the infestation is unlike anything they have seen in the northeast region.
"This is a once-in-a-lifetime event. We have no former history to work with," turf expert Deborah Swanson told the Associated Press over the weekend.
Patricia Vittum, an entomologist with the University of Massachusetts, was out of the office this week, but the message on her tape machine directed callers to the UMass website for more information about army worms.
The Latin name for the caterpillar is Pseudaletia unipuncta. There are many species of the army worm, but according to the Umass website the worm that everyone is seeing now is the common army worm.
But it's imprecise to talk about just one army worm. The habit of the worm is to congregate en masse in one place, and feed in densely packed groups that migrate from one site to another.
"They are mobile, they move. Hence the name army worm," said William Wilcox, the former agent for the Dukes County Extension Service on the Vineyard.
Mr. Wilcox is no longer the extension service agent and in fact there is no longer an extension service on the Vineyard, so people with questions about the army worm will need to contact an extension service on the Cape or at the University of Massachusetts at Amherst.
But Mr. Wilcox said that in his 20 years with the extension service he never encountered a large infestation of army worms. "This is not a typical pest that we see on the Island; this is unusual in our area." He said he remembers hearing old-time farmers on the Vineyard telling stories about army infestations many years ago.
Mr. Athearn said his uncle remembers seeing infestations of the worm 30 or 40 years ago.
The young caterpillars are pale green and look like inchworms. Mature caterpillars are about an inch and a half long, and dark green or gray-green with a stripe. Once the worms reach maturity they make cocoons and turn into moths. The moths lay more eggs that hatch into more worms. The army worm typically can have two cycles in a year, according to Ms. Vittum's information on the UMass extension service website, and the site warns that three cycles may be possible this year because of the early warm conditions. But in some areas the worms may only have one cycle.
"In other words, even though we seem to be blessed with populations of biblical proportions right now, there is a good chance that subsequent populations will move on to other areas - perhaps corn or field crops, or blow downwind. We can hope they are blown out to sea!" according to the website.
The website advises against the widespread use of pesticides against the worm, since the infestation appears to be a rare event. Also the damage caused by the worm is usually superficial since the worm feeds on the top foliage and not the roots.
Experts also write: "It is not clear whether the army worms can survive winter conditions in New England, but there is little doubt that the moths can fly into the region in large numbers each spring. We believe that moths arrived on one of the frontal systems that delivered thunderstorms in late May or early June, marking the end of a six-week mini-drought that much of New England experienced."
Often the worms attack corn, but their early arrival in New England preceded the corn crop, leaving succulent targets - lawns.
At Pimpneymouse Farm they found something even bigger and better than a lawn - a hayfield.
"I noticed these black spots on the driveway the other day and then my grandson came into the house and said there were caterpillars all over the driveway. I had noticed that the grass underneath the hay in the field looked brown, but I thought it was probably because of the peculiar conditions we were having," Mrs. Potter said.
She concluded: "Our southwest field is devastated. I have never in my entire life seen anything like it."