Armyworms and fall armyworms are the larvae (caterpillars) of moths. When they are numerous, they may devour the grass down to the ground. Their feeding causes circular bare areas in lawns or in heavy infestations whole lawns may be devoured. These larvae are 1 1/2 inches long; they are greenish to brown with alternating dark and light stripes. The best diagnostic features of the fall armyworm are its darker head with contrasting white to yellow inverted “Y” lines on the front of the head and four distinctive black dots on the top of each abdominal segment. The adults of the armyworm are tan with bronze front wings with a single white dot in the middle. Their wings measure about 1 1/2 inches across when expanded.

Read more about armyworms and other lawn pest in UT Publication 1158, "Lawn Insects: How To Control Them", found here.

Armyworms are primarily night feeders. Check for fall armyworms and other caterpillar pests in turfgrass by preparing a soap solution of 2 teaspoons of liquid dishwashing detergent in a gallon of water. Pour this solution over a 2-foot by 2-foot area (4 square feet). These caterpillars will be forced to the surface by the irritating soap solution. Sample periodically through the spring and summer and treat when any populations of these caterpillars are detected. Control is best done when the caterpillars are in their early stages and still small. If not treated, they can reach high population levels and totally defoliate fields or yards.

or chemical control recommendations, consult the Insect and Plant Disease Control Manual, UT Extension Publication 1690, found here. Please contact your local Extension office for specific pesticide recommendations.