STARKVILLE, Miss. (WJTV) – Fall armyworms have been a problem in Mississippi this summer, as they advance across much of the state in higher than normal numbers.
Blake Layton, entomologist with the Mississippi State University (MSU) Extension Service, said the armyworms are the most damaging insect pests of bermudagrass hayfields and pastures. They can defoliate an entire yard or field almost overnight.
“They are called fall armyworms because their numbers are highest in late summer and fall, and hay producers, cattlemen, turf managers and homeowners should expect to be dealing with this pest until frost,” Layton said.
Armyworms arrive each summer when moths migrate back into the state from the Caribbean, Mexico and areas of South America.
Fall armyworms are caterpillars that reach about 1½ inches long at maturity. When they metamorphose into moths, they are about ¾ inch long when resting with their wings folded.
The eggs hatch in two to five days, and the newly emerged larvae begin feeding on the underside of leaf blades. Their feeding habits result in tiny, white “windowpanes” in the leaf blades or a white frizzing of the leaf tips.
“Experienced cattle producers watch for this white frosting or frizzing of the leaf tips as an early warning of fall armyworm infestation,” Layton said.
There are treatment options for lawns, pastures, fields and golf courses. Rocky Lemus, Extension forage specialist, said that in hayfields and pastures, pyrethroids used alone often fail to control the caterpillars, but they are more successful when combined with a growth regulator. A better option may be to switch to a nonpyrethroid product.
“Producers need to pay attention to grazing and haying restrictions associated with the product used to treat their pasture and hayfields,” Lemus stated.
Homeowners can speed along the process with good watering, fertilizer and weed control. Both pyrethroids and nonpyrethroid products are available for lawns. Hose-end applicators work for small areas, while broadcast sprays work for large lawns.