By allowing ads to appear on this site, you support the local businesses who, in turn, support great journalism.
Armyworms marching through lawns and pastures
Placeholder Image

Over the last few weeks, the extension office has received numerous calls from anxious homeowners and frustrated farmers regarding the dreaded fall armyworm.

This pest has the ability to decimate a lawn or hayfield in a matter of days, often going unnoticed as they cause most of the damage at night.

If you have yet to check your lawn or pasture for armyworms, now is the time. Problems with armyworms generally start in early to mid-August in North Georgia, but they seem to have begun marching earlier than usual this year.

Fall armyworms will eat many kinds of grass, but they are particularly fond of Bermuda grass that is well-fertilized and watered. Homeowners frequently notice them after their grass starts to thin. Farmers often find the damage days before preparing to cut their hayfields.

Armyworms are susceptible to cold and are unable to survive even the mildest winters in North Georgia. Each year, armyworm moths, carried by air currents, make their way from Central and South America. The size and timing of the initial moth flights are two factors that influence the outbreak potential of this pest.

Armyworm damage often seems to appear "overnight." Frankly, it's not the young armyworms that cause the damage as they eat very little. Almost all the damage is caused by the oldest caterpillars that eat more than in all their juvenile stages combined.

Larger fall armyworms will quickly invade an uninfested area in search of food once an adjacent field or lawn has been defoliated. Large armyworms disappear almost as suddenly as they appeared, either burrowing into the ground to pupate or moving on in search of food.

The four stages of development are the egg, larvae, pupae and adult. The adult is an ash-gray moth with a wing-span of about 1 ½ inches. Moths become active at twilight and feed on nectar. They have an average life span of two to three weeks.

The female moths lay eggs at night in masses of up to several hundred in grass and on fence rails, lawn furniture, tree trunks, etc. The eggs hatch within two to four days. All the eggs (within a mass) hatch at about the same time.

The tiny, light-colored, black-headed larvae spin down to the ground on silken webs and begin to feed. As they grow, their bodies darken and noticeable stripes appear.

When fully grown, larvae may be up to 1 ½ inches long and vary in color from light green to almost black with several stripes along the body. Development from egg to fully grown larva requires about two to three weeks.

Once the caterpillar reaches maximum size, it burrows into the soil and forms a pupa. The moths emerge in about 10 to 14 days. Three to four generations per year are common in Georgia.

To inspect your lawn for armyworms, simply mix about 2 tablespoons of lemon-scented dishwashing detergent in 1 gallon of water and pour it over a 1 square foot area of the lawn. If armyworms are present, they will quickly come to the top of the sod.

As for control products, several choices are available to homeowners, including Bacillus thuringiensis (Dipel), Trichlorfon (Bayer Advanced), and Carbaryl (Sevin). Always be sure to read and follow label directions.

Billy Skaggs is an agricultural agent and Hall County extension coordinator. Phone: 770-531-6988; fax 770-531-3994.