Fall Armyworms

Fall Armyworm Poses Risks to Hayfields and Pastures

As we move into the later part of the summer, the risk of damage to hay fields, lawns, and pastures from fall armyworms greatly increases. We have already had scattered reports in the area to our south, which typically means we will see them soon. The fall armyworms can hatch out by the thousands each year during this time.

Since UGA Extension has an Agriculture and Natural Resources Agent in almost every county in the state, farmers can call in and report armyworm infestations on their farms, and the ANR agents can warn other counties. The agent can then assist the county farmers in how and when to control the armyworm populations. 

Armyworm Lifecycle

Fall armyworms can hatch out in large numbers, especially during periods of dry weather in late summer. They hatch out about the same time and start marching across hay fields, pastures, and lawns, eating everything green and living in their path. The whole process starts with a large number of light brownish colored moths laying clusters of eggs on blades of grass and other plants close to the ground. The eggs hatch in two to five days and become the caterpillars that cause all of the destruction.  They are about an inch and a half long when full-grown. Their body color varies from green or tan to nearly black and usually has an inverted white "Y" on their face. They feed on plant material for about 12 days and then pupate. After pupating for seven to fourteen days, adult moths emerge, being mainly active at night, and start the whole process over. Farmers and homeowners should be on the lookout for armyworm populations in hayfields, pastures, and lawns.

What to Do if You Find Armyworms

Once farmers (or homeowners) encounter these green-leaf-eating-machines, they need to take a count of the population. If there are more than three armyworms per square foot, they will need to spray an insecticide, such as Sevin 80S, Baythroid XL, Mustang Max, Coragen, Dimilin, or Karate. It is worth noting that most products available to homeowners under the brand name “Sevin” no longer contain Carbaryl, so be sure to read the label for the active ingredient prior to purchasing. These insecticides may have restrictions and precautions for use, so be sure to read and follow the label directions before using.

Hay producers have one other option in order to salvage the hay crop and stop the armyworm progression. If the hay crop is close enough to yield a decent harvest, they can go ahead and cut the grass and bale it. This will take away the food for the worms and they should not survive beyond the field. Farmers and homeowners should be on the lookout for additional damage to crops in Banks County. To help us keep track of armyworm infestations, please call the Banks County Extension office at 706-677-6230 or email zmccann@uga.edu to file a report and to receive additional recommendations for controlling these pests.