It’s a sad scene for many homeowners across the country: yards of green grass go brown in just a matter of hours. Fall armyworms are on the march, turning lawns—as well as farm crops—into battlefields of devastation at an “unprecedented” scale.
“They can easily munch their way through whatever, whether it’s a lawn or a park or a golf course,” Eric Rebek, an Oklahoma State University entomologist, tells Christine Fernando of USA Today. “They just lay waste to everything in their path, moving through just like an army on the move.”
The caterpillar infestation is attacking at an “unprecedented” level, Revek says, destroying lawns across the Northeast, Midwest, South and Southwest. Fall armyworms are an annual problem, though there can be a large concentration of these bug battalions every three to five years.
“This year is like a perfect storm,” Rick Brandenburg, a North Carolina State University entomologist, tells USA Today. “In my 40 years, I have never seen the problem as widespread as it is this year.”
One of the reasons it is so invasive this time has to do with weather patterns. Before fall armyworms became caterpillars, summer storm fronts blew moths far and wide so they could lay eggs in new, more fertile areas.
“The adults of these moths have been known to travel 500 miles, even more, in 24 hours,” according to an alert on Buckeye Yard & Garden onLine, posted by Ohio State University's Extension Nursery, Landscape and Turf team. “They can get into the jet stream and move vast distances, then drop down to find suitable host plants.”
Female moths typically lay up to 500 eggs on leaves of trees and plants overhanging grass. They also can put them on strips of grass and light posts. The eggs hatch in about five to seven days. The resulting caterpillars have a “Y” shape on the back of their heads and three stripes running down their bodies, reports Emily DeLetter of the Cincinnati Inquirer.
Once hatched, fall armyworms can turn lawns and crops from green to brown with yellow stripes in less than 48 hours. They work below the surface, chewing through roots and killing plants quickly as they suck up nutrients. Insecticides are needed to eliminate this foraging army but application must be made quickly to save lawns and crops.
Once grass is killed, it is best not to reseed right away because a second wave of marauders is likely to attack, Bethany Pratt, a Jefferson County horticulture education agent with the University of Kentucky Cooperative Extension Service, tells the Cincinnati Inquirer.
Watch for a second round of eggs, then counterattack as they hatch. Unfortunately, your grass is pretty much a goner no matter what.
“You’re going to plan on managing them and not controlling,” she says. “Nothing will ever do 100-percent control unless you’re also getting rid of your lawn.”