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What Are the Treatments for Army Worms on a Lawn?

By Susan Steele ; Updated July 21, 2017

Fall army worms are small brownish-green worms with stripes on their sides that resemble caterpillars. Every year adult moths come to the U.S. from South and Central America. The female moths then lay hundreds of eggs, which hatch within just a few days. When this occurs, it is only two to three weeks until the fall army worms are at the adult stage. This is the time when substantial damage can be done to a lawn.

Where Army Worms Appear First

Army worms typically arrive in southern Alabama each year between late July and the first week of August. Fall army worms are also commonly seen in other southern states, such as Florida and Georgia. Once they have arrived in the warmer areas of North America, they may also soon travel upward to the northern states.


Fall army worms can cause damage to a variety of different grasses. They are very partial to Bermuda grass that has been well cared for. Army worms tend to do damage to grass in scattered areas. If there are several small areas where the grass appears to be thinned down, it is a good indication that the lawn has been invaded by fall army worms. These worms normally feed during the daytime and rest at night.

Testing for Army Worms

If you suspect fall army worms have invaded your lawn, there are ways to make a definite determination. Find a 4 foot area where the grass seems to be sparse and perform a home soap flush on the lawn. Mix 2 tablespoons of dish washing liquid with 1 gallon of water. Pour this mixture on the ground and observe if any army worms rise to the top. If they are present, this will bring them to the surface within a few minutes. You can also shine a light on the area at night; any army worm moths that are present will fly out.

Chemical Treatments

Once you've confirmed that army worms have invaded your lawn, there are a variety of different chemical treatments you can use. Among these are pyrethroid insecticides and products that contain trichlofon, carbaryl or Bacillus thuringiensis. For mild cases, some insecticidal soaps may also get rid of army worms.


About the Author


Susan Steele has been an avid writer for more than 25 years. Steele's articles covering gardening and other topics have been published on a variety of well-known websites, such as eHow, Garden Guides and Answerbag. She graduated from Ashland Community and Technical College with a degree in data-entry operation.