Are Fall Armyworms Bad For My Lawn?


When the fall armyworms attack your yard, you should be prepared for a real lawn problem! Fall armyworms are bad for your lawn as they attack the healthy green grass, leading to excessive damage to your lawn.

Fall armyworms start appearing in large numbers in late summer or early fall, and most likely, the grass damage will happen from August through October. Each year, there are at least 3 generations of fall armyworms. They are susceptible to cold and cannot survive harsh winters.

These caterpillars will chew all the green leaves of your grass, therefore, it’s essential to identify them earlier and control their spread to minimize the destruction.

This article responds to all the questions you might have about the fall armyworms.


How Do You Identify A Fall Armyworm?

These are caterpillars that are about two inches long. Their bodies have green, brown, or black colored stripes, with darker stripes running along their sides.

At the top, each abdominal segment has two pairs of black spots from which stiff hair grows. On the front part of their head, you’ll see an inverted “Y” mark which is lighter in color than the head.

Fall armyworms have recently caused a lot of havoc in most lawns in Atlanta as they attack the yard in a large group, chew the green grass, and march off.

To identify them, it’s essential to first determine the type of grass you have on the lawn because, for the most part, these pests appear on bluegrass, fescue, and buffalo grass.

If you want to check for potential fall armyworm infestation on your lawn, pay attention to at least two of the following:

The increase of birds on your lawn indicates the presence of armyworms. The caterpillars are a source of food for the birds, such as the bobolink bird, the American crow, and starling, to name a few. Thus, the presence of these birds is a sign that there is plenty of food available.

If your lawn has got tell-tale brown spots on the grass.

As you walk on the lawn, you might notice some of the caterpillars on the ground.

In general, make sure to check for their presence in August and September, this is because the eggs have a high chance of surviving due to the rainfalls.



What Causes The Fall Armyworm Infestation In The Yard?

There are some seasons when your lawn will have a heavy infestation of armyworms, while some seasons you won’t experience the infestation.

The armyworms will invade your lawn in search of food. Researchers attribute the increased infestation of the grass with armyworms to the lower mortality rate of the young caterpillars and eggs.

Drought or other natural disasters in some areas can also trigger the infestation as the caterpillars will be moving slowly to survive in the adverse conditions and keep off the predators, therefore, seeking safe shelter in your lawn.

Lastly, if you have delayed harvesting crops in your yard, the armyworms may invade your lawn in search of food after other sources have been exhausted.


When Do Armyworms Come Out?

Experts consider the fall armyworms as nocturnal creatures that feed mainly at night. These caterpillars are very active during the night, destroying the lawn by chewing all the green grass.

During the day, they hide underneath the debris or in garden soil, and curl up and stay still when disturbed. Thus, if you want to notice grass damage, it’ll be better to check for them after dark when they come out. In turfgrass, you can make them come to the surface by sprinkling some soapy water onto the infested areas.


What Do Armyworms Eat? What Type Of Grass Do They Eat?

The fall armyworm caterpillars feed on stems, leaves, and reproductive parts of most green plants. The wide range of plants they eat includes corn, legumes such as soybeans, sugarcane, Johnsongrass, rice, sorghum, small grain crops, Sudangrass, peanuts, Timothy grass, and other plants found in your yard or garden.

Additionally, these caterpillars also feed on specific types of grasses which are their primary meals in most lawns. The grass that the fall armyworm prefers to feed on includes buffalo grass, fescue grass, ryegrass, and buffalo grass.



What Does Armyworm Lawn Damage Look Like?

It’s straightforward to identify a lawn that has been destroyed by the armyworms. However, the damage may vary in appearance and severity based on the type of grass you have and the level of maintenance.

In general, a lawn damaged by fall armyworms resembles drought damage. When the grass thins out and shows small patches that look burned or browned out, it’s the first sign indicating that these pests have attacked the lawn.

The grass quickly dehydrates and the blades of the grass may appear ragged. It happens as a result of the fall armyworm larvae chewing only the green and tender layers of the plant.

The young and small armyworms will skeletonize the surface of foliage and the inner surfaces of leaf sheaths. On the other hand, the larger ones will consume the whole grass leaves, starting from the outer edges.

The damage can lead to complete loss of foliage if there are great numbers of caterpillars attacking your lawn and if the grass is left untreated. Thus, you will notice bare spots on the lawn as the pests may have sheared the yard to the ground.

Lastly, these pests may leave matching rows if your yard has corn or plants with larger leaves.


Will Your Grass Recover From Armyworms?

When armyworms infest your lawn, they typically won’t kill the lawn grass completely, however, they will cause massive damage or destruction.

Your grass can recover from armyworm infestation only when the infestation rate is moderate or low. The reason is that the armyworm might have only chewed the blades but not the crown. In such situations, the grass will recover if you feed it and water appropriately. However, the grass may not recover if there has been a heavy infestation causing severe attacks during hot and dry weather.

Healthy and established Bermuda grass is rarely killed and usually recovers after fall armyworm infestation and defoliation because of the aggressive growth habit of its roots and stems. But newly established bunch-type grasses like fescue can be weakened, stunted, and killed by a severe infestation.


Does Mowing Kill Armyworms?

Lawn mowing may be essential in destroying or mechanically killing the armyworms, especially the larvae. Additionally, if you mow the grass that these pests have infested, the hay will dry out after cutting it down. Thus, the armyworms may starve to death or move on as they have lost interest in this food source. Besides, it’ll be good to supplement the mowing of the lawn with the use of chemical treatments or other control measures.


Fall armyworms are particularly harmful if they are present in your lawn in large numbers. Thus, it is important to treat the lawn as soon as possible to avoid further damage.

Guaranteed Green provides a wide variety of outdoor perimeter pest control services for lawns in Metro Atlanta, GA. We proud ourselves on providing fast and efficient service so don’t hesitate to reach out to us. Whether you’re looking for army worms lawn treatment, weeding, or fertilizing, or anything else, we are the best provider to render these services and leave you with a lawn you’re proud of.