Penn State Extension reports that they’ve had calls from across the state that hordes of armyworms are spreading through fields and lawns, destroying crops and grass as the go.
Infrequent invaders, armyworms are usually found in large numbers and can be found crawling across lawns that are near open fields.
Despite their name, armyworms are not actually worms. They are the late-stage larvae of armyworm moths. The species does not usually overwinter at this latitude. The adult moths fly up from the south to breed and lay eggs. Female moths can lay up to 2,000 eggs over their lifetime. Extension educators report that adult moths were found in Pennsylvania in May this year. Other states report similar arrival times.
The caterpillars are the only destructive life stage. They are smooth, unlike hairy gypsy moth larvae. They can grow to 1 1/2 inches long. Their coloring can vary including yellow, yellow-green, dark brown or black. But all include distinctive stripes that run the length of the caterpillar. Those stripes are usually salmon pink, brown or yellow.
Damage from armyworms initially looks like heat or drought stress. They rest during the heat of the day, and feed at dawn and dusk. Their natural predators are wasps and flies. It is rare that armyworms actually kill grass because they just eat the tops which grow back. Although, if combined with drought or other stresses, they can wipe out lawns.
Treatment includes placing pesticides labeled for use on armyworms around the edges of the lawn.
Has anyone found armyworms around the county?