How To Get Through Armyworm Season

There are many insects that are native to Southern lawns. A common, chronic pest in the Southeast is the Armyworm. Armyworms are most numerous in late summer or early fall. Here is some information about the insect, and some tips on how to determine if a lawn has an infestation.



Armyworms are brown to greenish in color and have stripes along their sides. Adults of the armyworm are light brown moths. The armyworm caterpillar is greenish when small and dark brown when mature. It has a light midstripe on its back with darker bands on either side. The midstripe ends in an inverted Yon the head. They grow to about 1.5 inch in length.



Armyworm damage may vary in appearance and severity according to the type of grass and management practices. The damage is often scattered and not confined to patches. Populations of armyworms often feed at the same time in the same location. They feed during the day and do not rest in a curled position. The grass may seem to thin out and develop brown spots that look burned. This is a result of the grass plants rapidly dehydrating after armyworm larvae have chewed off the tender foliage. For this reason, the damage often resembles drought damage. Armyworms feed predominately on grass leaves and stems, leaving the roots. This is fortunate for homeowners as their grass will likely recover from damage.



First, identify if the armyworm is present in the grass. Mix 1 TBSP of dishwashing soap in 1 GAL of water. Pour solution on grass. Insects will crawl to the surface if they are present.

A population of 3+ armyworms per sqft is a reasonable treatment threshold. If necessary, treat with insecticides while the worms are small. The bigger they are, the harder to kill. Consult product labels to see if it is effective against armyworms and for application rates and other instructions.

Tips for applying Insecticides to battle armyworms:

1. Cutting the grass prior to treatment will aid in control as the chemical will not have to penetrate as far to reach the armyworm.

2. Irrigate lightly prior to treatment as this may increase larval activity.

3· Apply treatments in the early morning or late afternoon when they are most active.



Eric Readinger