Written By Peter Honeycutt
Armyworms are most common in the fall season beginning mid-August and continue into the first of October. The first sign of armyworms are brown patches in the grass which rapidly grow bigger. These caterpillars feed at night and early morning. Another sign is several birds clustering on an area of turf grass. The caterpillar is approximately one and a half inches long with white stripes down its body. There are usually two angled stripes on the head and joined with a longer stripe to make a “Y”. If you see more than twenty-thirty smaller sized armyworms, it is time to treat. Each spring, stormy weather transports the moths north. Their eggs develop into the black caterpillars you see in your lawn.
It is not possible to kill armyworms while they are in egg stage, therefore they can only be killed once they hatch. The female moths lay eggs at night on light colored surfaces such as fence posts, woods, tree trunks, under tree limbs, etc. The eggs will then hatch within 2-4 days after the moths have laid their eggs and become armyworms.
It is a quick and easy fix if you see armyworms. Army Worms are fairly easy to kill with insecticides. There are many cost effective insecticides such as bifenthrin and permethrin. Sevin and Crosscheck are common products that are easy to find and use. Fall armyworms DO NOT kill grass but can weaken a lawn and they will not hurt it permanently. Armyworms can hatch at any time and come from anywhere. It is more common for armyworms to be near houses with woods nearby or after any type of storm. The moths can come from anywhere to lay their eggs.