Veteran Alabama farmers and producers know that hot, dry weather can be the perfect scenario for fall armyworms.

Kathy Flanders, an entomologist with the Alabama Cooperative Extension System, says this chronic pest was first spotted in May in Sumter County. But she says the problem only began to escalate in mid-July.

The pest was found in Jefferson County in mid-July. By July 17, Flanders says farmers and Extension agents had found fall armyworms in Baldwin, Chambers and Randolph counties as well.

"It started back in July, and the spread has not let up since then," says Flanders. "So far, more than a third of the state's counties are experiencing an outbreak of fall armyworms." You can see just where the worms are on the move with this interactive map.

She says that fall armyworms prefer lush, well-fertilized bermudagrass, and she encourages producers to check bermudagrass fields regularly for caterpillars or the appearance of brown circular patches.

"The first clue of an infestation may be the appearance of brown circular areas about 10 to 20 feet in diameter in an otherwise healthy hayfield or pasture."

She says the areas will enlarge quickly as the caterpillars eat the available food and spread outward in search of more food. From a distance, these patches can look like drought stress.

Identifying armyworms

Fall armyworm caterpillars will feed on almost all forage grasses, as well as corn, cotton and approximately 100 additional plant species. The caterpillars develop into moths that lay eggs, beginning the cycle again. In Alabama, there may be as many as five to six generations of this pest every summer.

Fall armyworms can be found on foliage at any time of day, but may be more easily detected early in the morning or late in the afternoon. In heavy infestations, you will see caterpillar droppings on the ground.