STARKVILLE, Miss. (WJTV) – Each year, Mississippi’s pastures, hay fields and lawns are threatened by fall armyworms.

Keith Whitehead, who works in Franklin County with the Mississippi State University (MSU) Extension Service, said no one knows each year how bad the fall armyworm problem will be or when the insects will show up.

“They’re going to show up eventually. They always do,” Whitehead. “It may be as late as September, but they move north from South and Central America.

In 2021, the caterpillars showed up in hay fields the first week of June, which was earlier than usual.

Many of last year’s armyworms were resistant to typical control methods, and growers had to spray with different chemical combinations to manage the pest in their fields.

“There are other places for these insects to be, like roadsides and non-farmed areas,” Whitehead said. “We’re not treating the whole county, just our production fields. Fall armyworms mature, pupate and turn into months, then return to our fields.”

Blake Layton, an Extension entomologist, said it is noteworthy that significant numbers of fall armyworms have not appeared in the state by the end of July.

“After last year’s unusually heavy and widespread fall armyworm outbreak, hay producers and turf managers are understandably anxious about what this year may hold,” Layton said.

According to the MSU Extension Service, pyrethroid chemicals make up the first line of defense against fall armyworms. However, some growers experienced control difficulties with pyrethroids last year, while others did not.

Layton recommended that hay producers who experienced control difficulties with pyrethroids alone last year may want to use a higher rate and tank mix the chemical with one of the insect growth regulator products.

Homeowners can protect lawns attacked by fall armyworms with pyrethroid sprays and other recommended treatments available at farm cooperatives or outdoor supply stores.