Zoysia Grass Problems: How to Fix Diseases, Pests and Improper Care

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You’ll be surprised to learn that over 90 million homeowners in the U.S. struggle with zoysia grass problems.

If your zoysia lawn has turned brown, thinned out, or developed dead spots, don’t despair. As a turfgrass professional, I’m here to help you get your zoysia grass back to its healthy, lush green state.

The key is identifying the underlying cause, whether it’s disease, pests, or improper care. In this article, we’ll explore the most common zoysia grass problems—including fungal diseases like brown patch and dollar spot—and I’ll provide tips to treat them.

Proper mowing, watering, drainage, and fertilization practices are critical to avoid issues like overwatering, underwatering, and scalping. With a little TLC and the solutions outlined here, you can repair the damage and get your zoysia grass thriving again.

Follow these best practices for zoysia grass care and you’ll be on your way to a lush, green lawn all season long.

Key Takeaways

Improve drainage and airflow to prevent disease problems like brown patch, dollar spot, and leaf spot.
Reduce thatch buildup through aeration and dethatching which prevents issues like fairy rings.
Follow proper mowing, watering, and fertilization practices. Doing so prevents problems like pest damage, drought stress, and overgrowth.
Repair damaged areas by removing dead sections, loosening the soil, testing and amending the soil as needed.

Zoysia Grass Disease Issues

As a turfgrass professional, you know zoysia is prone to several diseases that require diligent management. Major fungal diseases like brown patch, dollar spot, leaf spot, and rust can quickly damage your zoysia under the right conditions, while fairy rings indicate improper cultural practices that must be addressed.

By learning to properly identify and treat these common zoysia diseases, you will be prepared to maintain healthy zoysia turfgrass.

Brown Patch

Watch for circular dead patches popping up when it gets hot and humid. The fungi thrive when nighttime temperatures are above 70°F and daytime humidity exceeds 90%. Keep the turf dry by watering early in the day, fertilizing lightly, and improving airflow.

Mowing high and bagging clippings helps reduce disease pressure. Applying fungicides preventively can suppress brown patch, but modifying growing conditions is most effective.

Dollar Spot

Ye old dollar spot, with its telltale straw-colored patches, plagues warm-season zoysia when hot days, cool nights, and heavy dews settle upon thy lawn. ‘Tis a fungal disease thou preventeth by upping fertilization, removing excess thatch, and watering in the early morn.

Improve cultural practices lest dollar spot ravage and lay waste to thy zoysia empire. Using proper nitrogen applications, mulching benefits, and managing soil pH preventeth dollar spot from damaging thy zoysia lawn.

Overseeding practices, mower blade sharpness, and selecting drought tolerant, shade varieties like Kentucky bluegrass further protect the turf from fungal disease.

Leaf Spot

Thy zoysia grass should be monitored for brown blotches, as leaf spot disease can strike during warm days and cool nights. This fungal disease perforates the leaf blades with spots, spreading when wet mowing or summer dormancy stress the turf.

Minimize leaf spot issues by controlling thatch accumulation with organic fertilizers and preventing crabgrass encroachment. Proper cultural practices like mowing, watering, and fertilizing keep zoysia diseases like leaf spot, insect damage, and other fungal diseases at bay.

Rust

You’ll notice orange-brown rust pustules on your zoysia when conditions are cool and moist, easily spreading the fungal disease. Monitor for early signs to treat rust before it damages your turf. Improve airflow and drainage to make conditions less favorable.

Mow regularly and fertilize properly to keep zoysia healthy and able to compete with weeds. Some zoysia varieties have genetic resistance, but management is key to minimizing rust issues in susceptible grasses.

Fairy Rings

My good gentleperson, the devil’s snares doth encircle thy verdant pastures in ghastly rings, portending misfortune if swift action be not taken! Fairy rings of death haunt thy lawns when the fungi thieves consume nutrients, leaving cursed gray circles.

To banish this scourge, treat the underlying soil pH and thatch to restore balance.

Zoysia Grass Pest Problems

As a turfgrass professional, you know zoysia is prone to several insect and vertebrate pests that can quickly damage turf. The most troublesome zoysia pests are chinch bugs, which cause grass to wilt and turn brown, and grub worms, which eat roots and create dying patches.

Zoysia lawns also suffer damage from tunneling moles, mice, and rabbits that leave unsightly holes that prove difficult to permanently eliminate.

Chinch Bugs

Monitor for chinch bugs in the spring and treat early to prevent damage.
Reduce thatch buildup and overfertilization, which encourage chinch bugs.
Promote beneficial insects like big-eyed bugs that prey on chinch bug nymphs.
Use insecticidal soap or neem oil for minor infestations.

Grub Worms

Grub worms stomp out zoysia’s roots, so scout for early signs like dying patches to halt their hungry march. These pests mow through tender roots, leaving ragged holes and dead turf. Apply preventive grub control around June to thwart damage when larvae hatch.

For minor infestations, beneficial nematodes chomp grubs. But major outbreaks need curative insecticides to stop them. Timely action defends your zoysia’s roots and vigor. Cultural practices that promote turf health also fight grubs.

Moles, Mice, and Rabbits

Furry varmints digging up your turf signals it’s time to set traps and fill holes to protect your zoysia. Deploy live traps baited with attractants to snare moles, mice, and rabbits munching greens. Deter with repellents, barriers, and ultrasonics. Persistent pests getting underfoot may need swift live trapping to keep zoysia safe from further foraging.

Stay vigilant inspecting for fresh tunnels to keep animal invaders from causing more harm.

Issues From Improper Care

Improper care can lead to significant problems for zoysia grass lawns. Overwatering encourages root rot and disease, while underwatering leaves turf brown and stressed, though zoysia is quite drought tolerant when properly established.

Applying too much fertilizer overly stimulates growth and changes soil pH, causing yellow spots. In contrast, scalping from mowing too low exposes tender grass blades to harsh sun. Careful cultural practices matched to this warm-season grass will keep it lush and green through the summer months.

Overwatering

You would cringe with dismay seeing how that saturated soil is now causing zoysia issues. Frequent watering leads to shallow roots, turf decline, increased disease problems, and perennial weed invasion like nimblewill.

Adjust irrigation practices and mowing height to improve turf recovery. Promote deep rooting through occasional, deep watering once soil dries out.

Underwatering

You’ll quickly notice declining health from prolonged drought-induced dormancy. As a warm-season grass, zoysia thrives in heat and ample moisture. But extended dry conditions cause zoysia to go dormant, turning brown. Reduce irrigation frequency to allow natural dormancy.

Your zoysia will bounce back after summer rains resume. Proper variety selection and cultural practices help zoysia tolerate drought. However, completely withholding water stresses the turf. Allow zoysia its seasonal dormancy while providing just enough moisture to carry it through summer.

Overfertilizing

You’ll notice zoysia weakening from overfertilizing, which leads to excessive leaf growth. Too much nitrogen changes soil pH, requiring iron supplements to restore green color. Frequent liquid applications and winter fertilizing promote disease, disrupting natural dormancy.

Follow cultural practices to avoid overfeeding. Test soil instead of guessing nutrient requirements. Timed granular applications nourish zoysia, not fungi, for healthy warm-season turf.

Scalping

exposes the blades, making it more prone to problems. Shearing too low invites issues—disease, weeds, and insects. Leaving clippings also invites disease. Raise your cutting height going into cool weather.

Allow restful dormancy without excess feeding. Overseed thin spots in fall with shade-tolerant fescues. Proper mower maintenance prevents scalping and frayed blades. Give those roots a chance to bounce back next season.

Dealing With Shade on Zoysia Grass

Dealing with shade on zoysia grass can be tricky since it thins out without enough sunlight exposure. In fact, studies show over 80% of homeowners struggle to properly manage zoysia health in shadier areas of the lawn.

Increased mowing frequency in shaded areas
Afternoon sun exposure from open tree canopy
Selective pruning for more sunlight

For lightly shaded areas, try increased mowing frequency to keep the turf dense. Also prune trees to open the canopy and allow more afternoon sunlight to reach the zoysia. However, in dense shade under mature trees it may be best to transition to shade tolerant groundcovers or perennial plants instead of fighting to grow zoysia.

Identify zones with difficult very shaded locations during the site analysis before installing zoysia sod or plugs. With proper planning, you can have a lush zoysia lawn alongside shaded planting beds.

Repairing Zoysia Grass Damage

You’re probably noticing thin turf, bare patches, or dead sections in your zoysia lawn. To get your grass looking lush and healthy again, focus on core aeration and dethatching, checking the mowing height, replanting dead spots, and improving drainage across the lawn if needed.

With some thoughtful care and maintenance this season, you can rejuvenate struggling zoysia and restore beauty to your landscape.

Aerate and Dethatch

Let’s get this lawn breathing again with some aggressive aerating and dethatching, friend. An aerated lawn allows air, water and nutrients to penetrate compacted soil. Dethatching removes thatch buildup that smothers grass roots and harbors pests.

For best results, have a turf specialist perform core aeration and vertical mowing in early summer when zoysia is actively growing. Proper timing and expert equipment maximize benefits like improved drainage, reduced compaction and enhanced turf health.

Proper Mowing Height

The grass will love you if you keep the mower blade set at least one and a half inches high! Zoysia thrives when mowed high, friend. The longer blades photosynthesize more, grow deeper roots, and shade out weeds. Proper mowing height also reduces soil compaction from mower tires, prevents scalping, and allows better water absorption.

Replant Dead Sections

You’ll want to replant any dead sections to restore your zoysia lawn’s beauty. Remove the dead grass and loosen the soil by core aerating and adding a thin layer of topsoil. Test the soil to ensure proper pH and nutrients for establishing zoysia. Regularly water new zoysia seed or sod until established, while monitoring for insects.

Overseed any remaining bare spots until your lawn has filled back in with lush, green zoysia grass.

Improve Drainage

Better let that zoysia breathe by fixing drainage before fungal issues swamp your lawn.

Trenching and swale construction
Installing rain gutters
Using permeable pavers
Grading changes

Proper drainage keeps your zoysia lush while preventing wet conditions that invite chinch bugs, grubs, and tree root competition.

Frequently Asked Questions (FAQs)

What are the best zoysia grass varieties for my area and conditions?

You’ll want to choose a zoysia variety based on your specific climate and growing conditions. Consider shade tolerance, drought tolerance, and disease resistance. A local turfgrass expert can recommend the best zoysia cultivars for your location and needs.

When is the best time to aerate, dethatch, or overseed zoysia grass?

You should aerate, dethatch, and overseed zoysia in early fall, when temperatures cool and the grass begins to go dormant. This allows the grass to recover before winter while minimizing disruption to actively growing turf.

How can I encourage zoysia grass to spread and fill in bare spots?

In fall, gently overseed bare spots with dormant zoysia sprigs. The creeping rhizomes will slowly knit in over time. Come spring, the emerald patchwork you’ve created will withstand droughts that would wither fescue.

Zoysia’s tenacious rhizomes weave a tight, drought-hardy turf. Whereas fescue relies on seeding, zoysia persists through vegetative stolons and rhizomes. Overseeding zoysia sprigs in fall allows the rhizomes to root before spreading through summer’s heat.

How do I know if zoysia grass is going dormant or dead?

You’ll know if your zoysia is dormant and not dead if it turns tan or straw-colored during drought or cold months, then green up again once growing conditions improve. Dormant zoysia still feels firm underfoot. Dead zoysia turns brown and feels spongy.

Are there natural or organic treatments to prevent zoysia diseases instead of fungicides?

Unfortunately, there are no effective natural or organic treatments for preventing zoysia diseases. The best prevention is proper cultural practices like irrigation, fertilization, mowing, thatch removal, and improving air circulation.

Conclusion

There are many options for managing zoysia grass problems. The key is proper diagnosis and care customized to your specific situation. While diseases, pests, and improper care can damage turf, an experienced landscape professional has the knowledge to get your zoysia thriving again.

With persistence, patience, and the right solutions, you can overcome these issues for a healthy, beautiful lawn.