Common Zoysia Grass Pests & Diseases
Zoysia Insect Pests
There are many insects that care for your Zoysia Grass.
The most common Zoysia Grass Pests include:
- Azalea Caterpillars
- Bagworms
- Bermuda Billbugs
- Chinch Bugs
- Fire Ants
Azalea Caterpillars
To control azalea caterpillars, use biological insecticides such as Bacillus thuringiensis (Bt) or spinosad. These products are available from your local nursery or home and garden center. If you’re not sure which product to choose, ask the staff for help. Once you’ve decided on a product and purchased it, read the label for instructions before applying it to your zoysia grass.
The azalea caterpillar will grow into an adult moth with a brown body and white-striped wings that span 1 ½ inches across. The male has feathery antennae while the female has threadlike antennae, which makes them easy to distinguish from one another. The adult moths don’t damage plants but they do lay eggs on them in late spring, so keep an eye out for these pests in May and June near your zoysia grass.
Bagworms
Bagworms are not true worms, but caterpillars, the larvae of a moth. They are about an inch long and covered with a hard, brown, cone-shaped shell that is made up of materials stuck together from the plants on which they feed. The bagworm’s head and legs are tucked out of sight under this shell, and you need to look closely to see them as they stick out from the opening of their bags to eat the vegetation. Though very tiny when hatched in late spring or early summer, these creatures can grow rapidly to fill their bags with silk-like material bound together with leaf and plant parts.
Bermuda Billbugs
The Bermuda Billbug is a common lawn pest found throughout the United States. The billbug is a type of weevil that feeds on the roots of grass causing the lawn to die. Billbugs are especially common in lawns that are not well maintained.
Weeds and thick thatch in your turf provide a perfect home for these insects. Billbugs prefer sandy, warm soil and avoid soils with high clay and organic matter content. They also have a strong preference for bluegrass, fescue and ryegrass over zoysia grass varieties.
Chinch Bugs
Chinch Bugs: Chinch bugs are tiny insects that can inflict considerable damage to your lawn. They are difficult to control because they inject a toxin into the grass that prevents it from absorbing water. The combined effects of the toxin and water loss cause the grass to turn yellow in patches and then brown, eventually dying. Chinch bugs are most active during the summer months, but are especially active during dry periods.
Fire Ants
Fire ants are a big problem for homeowners in the southern United States. Fire ants are aggressive and can sting repeatedly. They also will defend their nests from pets and people. Baits that contain Spinosad or Abamectin are most effective against fire ants and will provide long-term control of the colony, even if not all fire ants eat the bait at first. Drenching is less effective because it kills only stock above ground level without killing the queen(s).
Sod Webworms
A lawn pest that can cause considerable damage to your zoysia grass is the sod webworm. The sod webworm is the larval stage of a small moth that comes out at night and flutters above the grass, rarely seen by people because of its nighttime activity. The adult moth lays eggs in the grass and when the larvae hatch from these eggs, they eat their way into your Zoysia lawn, often resulting in brown spots anywhere from 2 to 8 inches in diameter. If you have ever noticed areas of dead or dying grass without any other problems appearing to be present, you probably have a sod webworm problem.
Sod webworms feed on nearly all types of turfgrass on both sunny or shaded areas, but prefer warm-season grasses like St. Augustine and Bermuda as opposed to cool season varieties like fescue and bluegrass. They are more likely to attack dryer areas of lawns rather than moist ones so keeping your Zoysia lawn watered during hot summer months can help prevent a lot of damage caused by these pests.
There are many ways to get rid of sod webworms in your lawn with chemical insecticides being one option (though not the only one). Check out our article on How To Get Rid Of Sod Webworms for identification information and step-by-step instructions on how to control this common turf pest before it invades your perfect Zoysia turf!
White Grubs in Zoysia Grass
White grubs are the larvae of various beetles that feed on plant roots. Many adult beetles emerge from the soil in late summer. They lay their eggs and then die out by early fall. The eggs hatch, and then the grubs go into a dormant state through winter. When spring rolls around, they begin to feed again on your lawn’s roots until sometime in June when they go underground for another brief dormancy period. They resume feeding again in July before moving on to pupate into adult beetles by August.
Zoysia Grass Weeds
The first and most obvious way to rid your lawn of weeds is to pull them by hand. Be careful if they’re embedded in thatch, as it may be necessary to pull the weed and some grass along with it. If there are too many weeds for you to remove by hand, use a liquid weed killer or spread down mulch. Mulch will help choke out weeds and allow your grass to grow fuller.
It’s always best practice to attack weeds when they’re young, but if you have a serious infestation, talk to a professional who can recommend a weed and feed product that will work on your individual property. You can also do other yard work like overseeding your lawn or dethatching it if the problem is getting out of hand.
A weed problem can be an indicator that something else is wrong with your lawn. Make sure you take good care of your zoysia by giving it plenty of water and fertilizer so it doesn’t fall into disrepair.. If you know there are seasonal weeds coming up in spring/fall/summer, apply pre-emergent herbicides before the season begins!
A healthy lawn is a weed free lawn.
Everyone knows a weed is a plant that’s not wanted. But did you know that a weed isn’t always a weed? Yup, if the grass is growing in your lawn, then it’s turfgrass. If it’s growing somewhere other than your lawn, then it can be considered a weed.
Weeds can be removed through hand-pulling or use of herbicides (weed killers).
Weeds can also be controlled through methods such as mowing and fertilizing the turf. And weeds can even be prevented with proper care of the soil and turfgrass selection.
And just because something is called a “weed” doesn’t mean it has to be bad thing! Weeds can benefit the soil by cycling nutrients back into it. They are often deep-rooted plants that mine minerals from deep in the subsoil and bring them to the surface where they are available for other plants to use.