These ‘highly-destructive’ caterpillars may be hurting your SC yard. How to tell and fight them
If you live in South Carolina, you might have noticed an “army” of tiny, unwelcome visitors creeping into your yard. The fall armyworm, scientifically named spodotera frugiperda, can spell disaster for plants, but it isn’t actually a worm at all.
The caterpillars, frequently spotted in August in the Palmetto State, eventually grow into moths. They can’t survive in cooler climates, so fall armyworms spend winters in Florida, Texas and Central and South America. In the summer months, the moths spread north.
For gardeners, these insects can mean bad news.
“Often noticed in late-summer, these highly destructive caterpillars crawl through once pleasantly green areas, and in just a few hours, turn them into brown wastelands,” according to the Clemson University Home and Garden Information Center (HGIC).
As moths, fall armyworms are typically gray with white markings, but as caterpillars they can be gray, green, yellow or brown. The caterpillars are most easily identified by the distinctive yellow or white marking on their heads shaped like an upside-down letter Y.
You can also tell if armyworms have moved into your yard if you spot areas with silky, white thread, which larvae spin after hatching. When a fall armyworm moth makes itself at home, it can lay up to 1,000 eggs a night, according to HGIC. When those caterpillars emerge, they descend in droves on crops and other plants.
Although fall armyworms have more than 80 recorded host plants, according to the University of Florida Entomology and Nematology Department, the species most frequently chows on corns and grasses.
Because most of the caterpillars’ plant consumption happens later in their development, early damage isn’t always recognizable, but later stages can wreak havoc on your yard.
“In landscapes, initial damage from early instars (developmental stages of larva) may resemble drought or wilting symptoms in turfgrass, with later instar damage leaving a scorched or scalped appearance as most green foliage is consumed, leaving only grass stems,” HGIC says.
If you think you might have fall armyworms in your yard, HGIC recommends luring the caterpillars out by mixing one to two tablespoons of lemon-scented dish soap in one to two gallons of water until the mixture produces suds then pouring it over one square yard of healthy turf next to a damaged area.
If fall armyworms have settled on your property, insecticides with bifenthrin, Bacillus thuringiensis (B.t), cyfluthrin, cypermethrin, lambda-cyhalothin, permethrin or spinosad can clear the insects out, according to HGIC. However, it’s important to note that you should ensure the insecticide doesn’t come in contact with rainfall or irrigation for 24 hours for it to be most effective and prevent chemical runoff.
More information about fall armyworms in South Carolina is available on the HGIC website.
