7 Common St. Augustinegrass Pests

Closeup of St. Augustinegrass with text overlay of common lawn pests

Homeowners who live in the South, particularly Gulf Coast states, love St. Augustinegrass because it’s attractive, hardy, and really tolerates the scorching heat of the Sunbelt. But you know who else likes it? Certain creepy, crawly pests, and when they take up residence in your lawn, they can do some damage.

You don’t have to live with them, however. Identifying lawn pests and knowing how to get rid of them and keep them away is key to enjoying your hard-earned, beautiful lawn year-round. 

In this article:

Mole crickets

closeup of mole cricket on glass
Dmitry Baranovskiy | Flickr | CC BY 2.0

Mole crickets damage the grass by eating it below the surface, separating it from its roots.

Mole crickets have cylindrical bodies with small eyes and shovel-like forelimbs, which are highly developed to burrow. They tunnel into the ground, uprooting turf grass and seedlings. Their rampage picks up during summer, and the damage can progress quickly.


  • Brown, spongy areas in the lawn with normal green turf
  • Burrow mounds in the lawn
  • Jagged scars in grass blades

To test for the presence of mole crickets, add liquid dish soap like Dawn to two gallons of water and pour on a patch of lawn. The sudsy water will force mole crickets to the surface within a few minutes.

Treatment and prevention

Fortunately, effective defenses against mole crickets are pretty simple:

  • Dethatch grass to destroy mole cricket habitats.
  • Mow to make pesticide and fertilizer application easier.
  • Apply broad-spectrum insecticides according to the manufacturer’s guidelines.


closeup of nematodes under microscrope
snickclunk | Flickr | CC BY 2.0

Nematodes are microscopic roundworms that eat plant tissue, making it difficult for plants to absorb and transport water and nutrients. The bad news is, they’re among the most common of the St. Augustinegrass pests.

But don’t expect to be able to spot nematodes with the naked eye. Only a laboratory test can confirm their presence because they’re so tiny. Your local Extension office can help.


  • Less vigorous turf growth 
  • Thinning of the lawn
  • Weeds emerge

Treatment and prevention

Chemical control options of nematodes are limited. Experts instead recommend good lawn maintenance to keep them at bay. The goal is to promote good root health.

  • Raise the mower deck to ensure your grass is more than 4 inches, which encourages deep rooting. 
  • Fertilize on a regular schedule.
  • Aerate the lawn as needed.
  • Avoid applying too much nitrogen, which will promote leaf growth but not root growth.
  • You can replace the old turf and soil with pest-free topsoil in the damaged area.
Ground pearls look like pearls on the ground
James Castner | University of Florida Entomology & Nematology Department

Ground pearls

Ground pearls are another common St. Augustinegrass pest that feeds on roots. They appear in the spring and summer.

Ground pearls have small pearl-like bodies and can be found on the roots of grass or just below the surface of the soil. They are covered with a hard, spherical, yellowish-purple shell. In late spring, female ground pearls hide in the soil, then lay their eggs in early summer. The slender nymph will then emerge and infest the grass rootlets.


  • Ground pearl nymphs extract juice from St. Augustinegrass, leaving circular dead regions that resemble fairy rings. The patches turn yellow, and are especially prominent during summer.
  • The grass in the infested area turns brown and dries up during fall.

Treatment and prevention

The bad news is, there are few treatments that have proven effective at getting rid of ground pearls. Following are some tips for prevention. For a more extensive look at prevention and treatment, check out Lawn Love’s guide to getting rid of ground pearls.

  • Apply insecticides in May or early June when the insects are in the crawler stage. For effective control, continue applying for two or more years.
  • If you’re planting a new lawn or replacing pieces of sod, check the roots of the new sod to be sure you’re not planting infested grass.
  • Other cultural practices include proper mowing and irrigation, and application of  fertilizers. 

White grubs

closeup of white grubs in soil
Anna Gregory | Flickr | CC BY 2.0

White grubs are not worms at all but are actually the larvae of scarab beetles. They are dirty white or gray, with a brown head, and when resting they form a C shape. 

Grubs emerge from their winter slumber in spring, grow into adult beetles, lay their eggs and fly away. The eggs hatch in late summer or early fall, producing a new crop of grubs that feed voraciously on your lawn. This is the best time to exterminate them – when they’re immature and vulnerable to pesticide treatments.

Just because you have grubs, however, you may not need to treat your lawn. A healthy lawn can generally withstand some grub activity. The best way to check is to dig up a square-foot patch of lawn, about three inches deep, and inspect what’s underneath. If you spot six or more grubs in that square-foot of soil, your lawn may require treatment.


  • Brown or yellow patches on the lawn
  • Wilting of the turf grass
  • Spongy areas in the lawn

Treatment and prevention

  • The best time to treat grubs is in the early fall – September and October – when they are young and vulnerable.
  • Some chemicals, such as carbaryl and trichlorfon, have been shown to reduce grub populations.
  • The best way to avoid grubs is a strong lawn maintenance program. A healthy lawn can sustain damage but recover over winter or when the white grubs mature.


closeup of a billbug on blade of grass
Katja Schulz | Flickr | CC BY 2.0

Billbugs are a type of weevil – black or grey in color – that attack grass stems and make their way into the root system. They are present at all times; no season hinders their activity. They also have long, narrow snouts protruding from their heads, about a third of their total length.


  • Thinning of the turf
  • Brown patches on your lawn
  • The lawn seems to suffer from drought stress

Treatment and Prevention

  • Mow grass regularly.
  • Fertilize on a regular schedule.
  • Water to prevent drought stress and stimulate new growth.
  • Remove excess thatch.
  • Use insecticides in early May to control billbugs.

Chinch bugs

closeup of black chinchbug in mulch
jacinta lluch valero | Flickr | CC BY-SA 2.0

Chinch bugs are common in the South, particularly in Texas and Florida. They attack weak St. Augustinegrass by injecting a toxin that prevents water movement and kills the grass completely. Chinch bug damage can easily be confused with grass diseases because of the large brown patches they create on lawns.

Chinch bug nymphs are red with a pale white band, while adult chinch bugs are black and have white wings. When disturbed, they hide in the soil. You can identify chinch bugs by using the floating method.


  • Irregular patches of dead or stunted grass with a yellow halo
  • Circular or semi-circular brown spots on the grass

Treatment and prevention

  • Use pesticides to control chinch bugs on your lawn.
  • Mow your lawn vertically to reduce thatch.
  • Mulch or recycle grass clippings to minimize the application of fertilizer that increases thatch build-up.
  • Aerate your lawn to increase air circulation.
  • Apply a tiny layer of sand to increase the microbial activities that will help decay the organic matter in your lawn.
  • You can also use chemical control methods such as insecticides containing carbaryl or any pyrethroid insecticides to thin the chinch bug herd.
  • Additionally, you can prevent chinch bugs by planting improved St. Augustinegrass with reddish stolons that are chinch bug resistant.

Armyworms and cutworms

closeup of a southern armyworm
USGS Bee Inventory and Monitoring Lab | Flickr | Public Domain

Armyworms and cutworms eat flowers and anything green on the lawn. They feed on the crowns and leaf blades near the surface of the soil, forming circular patches. In sunny conditions, they hide in thatch, grass clipping, or mulch on the lawn.

Cutworm larvae are dull or brown and curl into a C shape when disturbed, while adult cutworms are dark brown with streaked forewings.


  • Circular cut areas of grass
  • Grass leaves disappear

Treatment and prevention

  • Irrigate and fertilize regularly.
  • Properly drain your lawn. Cutworms and armyworms flourish in wet areas.
  • Practice proper thatch management to reduce armyworm hiding spots.
  • Apply insecticides to dry grass. Consider treating the entire yard because armyworms scatter easily.
  • Control armyworm and cutworm infestations by applying a combination of pre-emergent Bifen granules and Cyonara or eco granules every four months to prevent them from invading your lawn.

The takeaways

St. Augustinegrass is affected by most pests. If your lawn is already infested, identify the pest and get the necessary treatment for your lawn.

You work too hard on your lawn to let bugs have their way with it. Lawn Love lawn care professionals can help you maintain a healthy lawn.

Main Photo Credit: Photo by Jeff Herman with text overlay of lawn care pests commonly found in St. Augustinegrass

Millicent Onchari

Millicent Onchari is a freelance content writer. She is passionate about digital marketing, fashion and design, gardening, and health and wellness.