An infestation of True Armyworms was identified last week in a hay field in central St. Lawrence County, prompting growers to take an extra look at their grass and corn fields.
According to Kitty O'Neil, a regional field crops and soil specialist with the Cornell Cooperative Extension, many of the worms were more than an inch long and nearing the point where they would pupate, the beginning of the process when a worm becomes a moth.
"It's very impressive when you see them at that density doing that kind of damage," O'Neil said. "This is probably finding five or six caterpillars per square foot of the field, so they're kind of everywhere."
She says armyworms have the ability to cause extensive damage if not caught in time, as was the case in St. Lawrence County.
"They can do a lot of work in a short amount of time, especially at the end of that larval stage when they're kind of reaching their peak size and doing the maximum amount of damage," O'Neil said. "On Monday, over just a couple of days they removed pretty much all of the reed canarygrass from a reed canarygrass/alfalfa mixed hay field."
O'Neil also says the recent handful of armyworm infestations are continuing to hurt fields that have already taken a hit this season.
"This is a season where a lot of the forage crops that will be stored for the winter are already not going to yield real well, because of the weather patterns we've been enjoying," O'Neil said. "This is just one more stress now that people need to be aware to look for them and if they can catch them early enough, they can be controlled a bit."
Had the worms been discovered only one or two weeks earlier, damage could have been contained by using an insecticide spray. O'Neil says there is some relief, as she doesn't expect there to be a third generation of armyworms this summer. But she suggests growers scout their fields for any possible sporadic infestations.