Throughout New York, a voracious caterpillar called the armyworm is on the march.
Earlier this month the New York Department of Agriculture & Markets warned crop growers of the presence of armyworms in several parts of the state, including western and northern counties, with the damage being especially bad in western areas.
“There are a lot of them, and they’re causing severe damage,” said Aaron Gabriel, the educator for Cornell Cooperative Extension’s Capital Area Agriculture-Horticulture Program. But the infestation is also spotty, he said, with the armyworms attacking certain fields while bypassing others.
“Western New York is getting hit very hard, but we’re getting reports of them in every county in New York,” Gabriel said.
He’s received calls about armyworms from about two dozen local farmers. One farmer harvested his hay a couple weeks ago and realized that worms had killed his new crop. “There was a big, brown dead spot in his field,” Gabriel said.
Armyworms feed on crops such as corn, hay and barley, and farmers are encouraged to keep an eye on their fields for signs of infestation. According to the state, it has also been known to infest vegetables, fruits, legumes and weeds.
The last significant infestation of armyworms occurred in 2008, and prior to that in 2001.
“By some accounts, this year’s infestation is surpassing those experiences,” the press release from the Department of Agriculture & Markets reported.
James Czub, of the Schaghticoke-based West Wind Farms, grows corn and soybeans in five different counties: Saratoga, Washington, Rensselaer, Ulster and Oneida. He said that because he was late in planting his crops, the insect was “mostly through its life cycle” by the time it got to his fields in Utica, where farmers have experienced “incredible pressure” from the worms.
“We’ve been fortunate,” Czub said. “We’ve seen armyworms here and there, but not at the economic threshold where it makes sense to treat them.”
The pests are migratory. They overwinter in the south and travel northward as moths in the spring, laying eggs that hatch into caterpillars. These caterpillars invade crops and lawns en masse, marching in lines from one source of food to another, leaving destroyed fields in their wake.
“They’ve been here for about three weeks,” Gabriel said.
Chris Logue, the executive director of Cornell Cooperative Extension of Schenectady County, said that his office hasn’t received any calls about worms in Schenectady County, but “they’re on our radar. We’re keeping an eye on things.”
Armyworms travel to New York every year, but typically in smaller numbers.
“I see armyworms every year,” said Tim McCabe, New York state entomologist. “It’s the large numbers that’s unusual. We only see that once or twice a decade.”
The armyworm population is usually kept in check by parasites, diseases, insects and birds. But the pest has thrived this year, which experts attributed to a severe drought in the Southwest, which killed off many of its natural predators, enabling it to thrive, and tropical storms that carried it to the Northeast in greater numbers than usual.
Severe armyworm infestations can only be dealt with using pesticides, McCabe said. “I can’t think of a non-insecticide way of handling their numbers. It’s like trying to figure out how to stop a hailstorm.”
One way to avoid damage is to harvest crops before the worms arrive and remove their food source, Gabriel said. “They’ll move en masse to another field.”
In its early stages, the armyworm is smooth and cylindrical in shape, with pale green to brownish coloring, while the mature armyworm has orange, white bordered stripes running the length of its body. They usually feed at night, which enables them to inflict significant damage without being detected.
A second generation of armyworms is expected in July.
“We might get two or three generations this summer,” McCabe said.
But the insect does not overwinter in the North and will disappear with cold weather.