PHILADELPHIA -- An invasion of armyworms is turning lawns throughout the Northeast a sickly brown and baffling experts, who can only guess that the source of the infestation was the winds of Tropical Storm Allison.
"They haven't been this bad in the Northeast in over 25 years," said John Buechner, director of technical services for Lawn Doctor Inc., a national lawn care company. "We're finding them from central Pennsylvania up through Boston."
Earlier this spring, parts of the Midwest experienced one of the worst armyworm outbreaks entomologists had seen. But the theory that armyworm moths, which can lay 300 eggs at a time, were blown northeast by the tropical storm in June is not easily proved.
Robert Leiby, director of the Lehigh County Penn State extension office in central Pennsylvania, says he started hearing about armyworms in the area the last week of June and the reports have gotten worse.
"People are calling and saying that they went away on Friday and that when they came back on Monday the lawn was gone, except for the bits of clover," said Karen Bernhard, assistant horticulturist and entomologist with the extension office in Lebanon County.
Two or three generations of armyworms can occur annually. The moths' eggs become tiny, hard-to-detect larva that grow into 1 1/2-inch-long brown or gray caterpillars with voracious appetites.
"It's pretty safe to say that lawns from northern Delaware all the way up to Maine have been damaged," said Brian Feldman, who manages TruGreen ChemLawn companies in the region. "It's definitely an epidemic."
JoAnn Dunn was proud of the thick grass in her yard in West Long Branch, N.J., until about a week ago.
"I was walking across the yard and could hear this snapping under my feet. It was the worms," she said. A day later she saw caterpillars on her patio and driveway.
"From one side to the other, and you could actually see my lawn moving," she said. "You could see them crawling through the grass, hanging off the top of the blades. It was absolutely disgusting."
Armyworms also can wreak havoc on farms, munching orchard grass, hay and corn. Dennis Calvin, an entomologist at Pennsylvania State University, said in some cases the worms have taken the corn down to the ground.
Tom Durkis, the state entomologist in New Hampshire, said in 25 years he hasn't seen the pest as bad as it is this year.
"As quickly as they come, they could disappear," he said. "It's very hard to predict."
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