How to Get Rid of Armyworms

Armyworms live up to their name when it comes to “marching through” and destroying your lawn. When an infestation occurs, your sod can be destroyed as quickly as overnight or in a few short days. We are here to help you fight the battle against these pesky intruders.

What is an armyworm?

An armyworm is the caterpillar of a moth who migrates across the state of Georgia every year. Although we’re in the South, moths do not typically survive our winters, but our summers are perfect for their babies. The northern parts of Georgia typically see large quantities of armyworms in late summer and early fall. A moth lays eggs in batches of a few dozen to several hundred. The lifecycle of an armyworm is fast paced, as they hatch after a few days and within a month, they will be an adult moth, meaning the cycle will start over. This month of the “armyworm stage,” however, can destroy your lawn — and it happens fast.

Are you worried your lawn has armyworms? There are a few key characteristics to look for on the worms. Armyworms will typically measure 1.5 to 2 inches long and their heads, although varying in color, have a distinctive inverted “Y” mark. Their bodies have a series of brown, red, green or yellow stripes down their back and sides. The adult moths are about 1.5 inches across.Their front wings are dark gray with light and dark spots and their hind wings are a pale gray-white.

Does your sod have armyworms?

The first indicator of an armyworm infestation is the presence of a lot of birds — birds love to feed on worms so an abnormal amount in your lawn would attract them. When looking at your lawn, these are some key indicators of armyworm damage:

● ragged or chewed grass blades
● chewing of just the green layer of grass
● grass sheared to the ground (creating care spots)

If you see a small brown spot in your lawn that starts to increase in size, check it out because armyworms work fast! The stage of life of the armyworms also show different signals. Large armyworms are easier to find, not just because of their size, but because they are more active during the day and their droppings (referred to as “frass”) are typically easily identified where they are feeding. Smaller armyworms are harder to see because they stay in the canopy during the day, meaning their feeding and resulting damage is harder to see. An easy way to test for armyworms is by pouring soapy water on your lawn. Mix ½ cup of dish detergent with 1 gallon of warm water. Pour all of the mixture on one spot, where the lawn seems weakest. Wait 1-15 minutes. If you have worms, they will rise to the surface.

Fixing the problem

If identified early enough (when the caterpillars are half an inch or smaller), a harmless bacterium called Bacillus thuringiensis (Bt) can be sprayed on your lawn, as it is meant only to kill caterpillars. However, this won’t work on mature caterpillars and in that case, you will need an insecticide, preferably one that will attach to the end of your hose for easy application such as Sevin Spray. Unlike most other treatments for your grass, insecticides for armyworms should be applied to your lawn in the late afternoon or early evening since armyworms eat into the night. This will ensure that you are taking care of all the armyworms, no matter their size.

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