Fall Armyworms Are Back: What CSRA Homeowners Should Watch for This Fall
Late summer brings plenty of challenges for lawns around Augusta, Evans, Martinez, Grovetown, North Augusta, Aiken, and the surrounding CSRA. Heat stress, afternoon storms, weeds, and fungal problems can all leave grass looking a little worse for wear by August.
But if an otherwise healthy lawn suddenly starts turning brown or looks like it has been scalped almost overnight, there may be something else going on.
Fall armyworms are one of the most destructive late-summer turf pests in Georgia and South Carolina, and now is the time for homeowners to start watching for them.
Despite their name, fall armyworms are actually caterpillars. When populations are high, hundreds or even thousands can move through a lawn feeding on grass blades. Damage can happen surprisingly quickly, which makes recognizing the early signs especially important.
What Are Fall Armyworms?
Fall armyworms (Spodoptera frugiperda) are the caterpillar stage of a moth that migrates into Georgia and South Carolina each year.
According to the University of Georgia Cooperative Extension, fall armyworm moths do not typically survive Georgia winters. Instead, moths move north from warmer areas such as Florida during the spring and summer, often traveling with weather fronts.
It takes several generations for populations to spread throughout the state, which is one reason fall armyworms become such a noticeable problem during late summer and early fall.
The same thing happens in South Carolina. Clemson Cooperative Extension identifies fall armyworms as a significant turfgrass pest that commonly becomes noticeable during the summer months.
By late August, CSRA lawns are firmly within the window when homeowners should be looking for activity.
Why Are They Called Armyworms?
The name makes a lot more sense once you see a serious infestation.
Fall armyworms can appear in large numbers and move together across turf while feeding. From a distance, the advancing damage can almost look like a line moving across the lawn.
One section may still be green while the area behind the caterpillars looks brown, thin, or scalped.
The “army” effect happens because adult moths can lay large masses of eggs. UGA reports that egg masses can contain anywhere from a few dozen to several hundred eggs, while Clemson notes that a female moth may lay hundreds of eggs during a single night.
When large numbers hatch around the same time, there can suddenly be a lot of hungry caterpillars sharing the same lawn.
How Quickly Can Fall Armyworms Damage a Lawn?
Very quickly.
Fall armyworms spend roughly two weeks in their caterpillar stage during warm summer conditions, and that is when they feed on grass.
The frustrating part is that the smallest caterpillars do relatively little visible damage. As they grow, their appetite increases dramatically.
Clemson reports that more than 90 percent of their total foliage consumption occurs after the fourth larval stage. In other words, a lawn can look relatively normal while young armyworms are present and then deteriorate rapidly once the caterpillars become larger.
That is why homeowners sometimes feel as though the damage appeared overnight.
A healthy lawn on Monday can look dramatically different by Wednesday if a large armyworm population is actively feeding.
What Does Fall Armyworm Damage Look Like?
Early armyworm damage is easy to confuse with other lawn problems.
At first, grass may appear:
- Wilted
- Drought stressed
- Thin
- Discolored
- Ragged along the leaf edges
As feeding becomes more severe, the lawn can develop larger brown or tan areas.
Heavily damaged turf may look as though it has been scalped extremely short, because the caterpillars consume much of the green leaf tissue while leaving stems behind.
One clue is how quickly the damage spreads.
Drought stress or many turf diseases tend to develop differently. Armyworm damage can advance noticeably across the lawn as the caterpillars move into fresh grass.
How Can You Identify a Fall Armyworm?
If you find caterpillars in damaged turf, look closely at the head.
One of the easiest identifying features of a fall armyworm is a pale upside-down “Y” marking on its head.
Mature caterpillars can grow to approximately 1½ inches long and may range from green or tan to brown, gray, or nearly black. Their bodies also have stripes running lengthwise.
You may see the caterpillars feeding during the early morning or late afternoon, when they tend to be more active.
Another surprisingly useful clue is birds.
If a large number of birds suddenly seem extremely interested in one particular section of your lawn, take a closer look. Birds feed on armyworms and may discover an infestation before the homeowner realizes anything is wrong.
Think You Have Armyworms? Try a Soap Flush
If your lawn is showing suspicious damage but you cannot find the caterpillars, Clemson recommends a simple scouting technique known as a soap flush.
Mix approximately 1 to 2 tablespoons of lemon-scented dish detergent with 1 to 2 gallons of water. Slowly pour the mixture over about one square yard of healthy-looking turf immediately beside the damaged area.
If armyworms are hiding down in the grass canopy, they should begin coming to the surface within several minutes.
This can help determine whether caterpillars are actually responsible before assuming a brown patch of grass is caused by drought, disease, or another lawn problem.
For homeowners who would rather not spend the evening interrogating their lawn with dish soap, Stokes can also inspect suspicious turf and help determine what is causing the damage.
Why Newly Installed Sod Can Be Especially Vulnerable
Armyworms can affect established lawns, but newly installed sod deserves extra attention.
Adult armyworm moths are attracted to young, actively growing grass. Newly installed sod is also typically being watered and fertilized regularly while it establishes, producing exactly the lush growth caterpillars prefer.
UGA notes that armyworm infestations are common during the first 30 to 60 days after sod installation.
Established turf will often recover from armyworm feeding once the caterpillars are controlled, although the lawn may look rough for a while.
New sod and recently sprigged turf can suffer more serious damage because the grass has not yet developed a strong root system.
If you’ve had sod installed this summer, checking the lawn regularly through late summer and early fall is especially worthwhile.
Which Lawns Do Fall Armyworms Attack?
Fall armyworms feed on several turfgrasses common throughout Georgia and South Carolina.
They are particularly associated with grasses such as bermudagrass, but they can also damage other turf species.
They may appear in:
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Residential lawns
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Newly installed sod
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Athletic fields
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Golf course turf
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Pastures
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Hayfields
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Commercial landscapes
Armyworm moths do not particularly care whether a patch of grass belongs to a farm, golf course, neighborhood entrance, or meticulously maintained backyard.
If suitable turf is available, it can become a target.
What Should You Do If You Find Fall Armyworms?
The most important thing is to act early.
Small fall armyworms are generally easier to control than mature caterpillars, and early treatment limits the amount of grass they can consume.
Once caterpillars become large, they may be close to finishing their feeding stage anyway, meaning much of the lawn damage has already occurred.
UGA and Clemson both recommend monitoring lawns closely during periods when fall armyworms are active so infestations can be identified before severe damage develops.
If you suspect armyworms:
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Inspect the border between healthy and damaged turf.
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Look for caterpillars during early morning or late afternoon.
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Check caterpillars for the inverted “Y” marking on the head.
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Watch for unusually concentrated bird activity.
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Use a soap flush if caterpillars are difficult to find.
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Avoid assuming the lawn simply needs more water.
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Have the problem identified and treated promptly if armyworms are confirmed.
Simply increasing irrigation will not solve an armyworm infestation. The caterpillars are physically eating the grass blades.
Will the Grass Grow Back After Armyworm Damage?
Thankfully, an armyworm infestation does not automatically mean the lawn is dead.
Established, healthy turf can often recover because fall armyworms primarily consume the grass foliage rather than the root system.
Once the caterpillars are controlled, appropriate watering and normal lawn care can help the turf produce new growth.
Recovery depends on how severely the lawn was damaged, the health of the grass before the infestation, weather conditions, turf species, and how quickly the armyworms were controlled.
Newly installed sod or already-stressed turf may have a more difficult time recovering.
Late-season damage can also take longer to disappear because grass growth begins slowing as temperatures and daylight decrease heading into fall.
Can Fall Armyworms Come Back After Treatment?
Unfortunately, yes.
Treating the armyworms currently feeding in a lawn does not prevent another adult moth from flying into the area later and laying a new batch of eggs.
UGA explains that fall armyworms can complete their life cycle in approximately four weeks during warm summer weather. Multiple generations can therefore occur during the same season.
This is why monitoring should continue even after an infestation has been treated.
If your lawn has already experienced armyworms once this year, keep checking it as we move through September and early fall.
How Stokes Can Help With Fall Armyworms
Fall armyworms are a problem where timing matters.
Once large caterpillars have eaten their way across the lawn, treatment cannot magically put the missing grass blades back. Catching the infestation while the caterpillars are still small gives us a much better opportunity to stop additional damage.
Stokes Mosquito and Pest Services offers lawn pest treatments for fall armyworms throughout the CSRA.
If you notice rapidly spreading brown areas, ragged grass, unusual bird activity, or caterpillars moving through your lawn, we can inspect the property, confirm whether fall armyworms are responsible, and recommend the appropriate treatment.
We serve homeowners throughout Augusta, Evans, Martinez, Grovetown, North Augusta, Aiken, and surrounding CSRA communities.
The important thing is not to wait several days hoping the lawn will improve on its own. Armyworms have a rather inconvenient habit of using those several days to eat more of it.
Frequently Asked Questions About Fall Armyworms
When is fall armyworm season in Georgia?
Fall armyworms generally become most noticeable in Georgia during late summer and early fall. UGA explains that moths move northward from warmer areas throughout spring and summer, with several generations developing before populations become widespread across the state.
Are fall armyworms active in South Carolina?
Yes. Fall armyworms are a common summer and late-season turf pest in South Carolina. Clemson Extension currently monitors fall armyworm activity across the state and recommends watching lawns and turf carefully for signs of feeding.
What is the first sign of fall armyworms in a lawn?
Early damage may resemble drought stress or wilting. Homeowners may notice ragged grass blades, thinning areas, discoloration, or a distinct boundary between damaged and healthy turf. Large numbers of birds feeding in one area can also be an early clue.
How fast can armyworms destroy a lawn?
Severe damage can develop very quickly when large numbers of mature caterpillars are feeding. Most of their foliage consumption occurs during the later stages of larval development, which is why a lawn can appear to deteriorate suddenly.
How do I know if a caterpillar is a fall armyworm?
Look for a pale inverted “Y” marking on the head. Mature fall armyworms can reach approximately 1½ inches long and usually have longitudinal stripes along their bodies.
Do fall armyworms kill grass?
They primarily eat the foliage rather than the roots, so established healthy lawns can often recover after the infestation is controlled. Newly installed sod and severely stressed turf are more vulnerable to lasting damage.
Can fall armyworms return after treatment?
Yes. Adult moths can continue moving into an area and laying new eggs, allowing multiple generations to occur during the same season. Continued monitoring is important through late summer and fall.
Does Stokes treat fall armyworms?
Yes. Stokes Mosquito and Pest Services can inspect and treat fall armyworm infestations around residential lawns throughout the CSRA. Early treatment is especially important because smaller caterpillars are easier to control and have caused less damage.
Keep an Eye on Your Lawn This Fall
Late August through early fall is prime time to start watching for fall armyworms around the CSRA.
Take a look at your lawn every few days, particularly if you have bermudagrass, recently installed sod, or turf that suddenly begins looking stressed despite adequate water.
The sooner an infestation is identified, the better the chances of stopping the caterpillars before extensive damage occurs.
If something seems to be eating its way across your lawn, don’t wait until the entire yard turns brown to investigate. Stokes Mosquito and Pest Services can help identify fall armyworms and provide treatment throughout Augusta, Evans, Martinez, Grovetown, North Augusta, Aiken, and surrounding areas.
