Fall armyworms have been found in Georgia hayfields and pastures earlier than normal this year, warns Mark Crosby, University of Georgia Extension agent for Emanuel County.

He urges hay growers to scout fields regularly for the pest. Its ash-gray moths deposit eggs by the hundreds in hayfields and pastures, and the eggs hatch within four days. Black-headed larvae spin to the ground, feed on vegetation, fully develop in two to three weeks, then burrow into the soil. Ten to 14 days later, moths emerge and the cycle continues.

Three to four generations of fall armyworms can occur during one summer season. The damage can be significant, Crosby says.

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Hay growers should determine how many armyworms are in their fields, then decide if pesticide treatment is needed, he adds. According to University of Georgia entomologists, when three or more feeding caterpillars – at ½” in size or larger – can be found per square foot, it’s time to apply chemicals.

Most pyrethroids labeled for use against armyworms are effective, including Mustang, Max, Baythroid, Karate, Tombstone, Intrepid, Prevathon, Sevin, Coragen, Tracer and others.

Growers with fields needing immediate treatment, or needing extra time between spraying and hay harvest, should consider adding Dimilin to their spray tanks, he adds. That chemical protects the plant tissue until the hay is cut.

For more information, contact the Emanuel County Extension Office at 478-237-1226 or email Crosby at pmc@uga.edu.