If you’ve fought lawn fungus in South Florida, you know how it goes. A brown circle shows up in November. You treat it. It fades. Next fall it’s back, a little bigger, in the same spot. After a couple of years you start to wonder whether the problem is really the fungus, or the grass you’re growing.
A lot of the time, it’s the grass.
Our heat, humidity, afternoon storms, and mild winters give fungal diseases something close to a year-round season, and some cultivars handle that pressure far better than others. Picking a disease-resistant variety won’t make your lawn bulletproof. What it does is cut down on the outbreaks, the fungicide bills, and the patch repairs, and in the case of lethal viral necrosis it can decide whether your lawn survives at all.
Below we break down the diseases that actually matter in Palm Beach County lawns, then go through every major South Florida cultivar and how it holds up against each one. Where we can, we’ve leaned on University of Florida (UF/IFAS) research instead of sod-farm marketing.
The short answer: For St. Augustine, CitraBlue has the strongest all-around disease profile. For zoysia, CitraZoy is the standout because large patch, zoysia’s biggest disease problem, has never been observed on it in UF trials. If your neighborhood has lethal viral necrosis, stick with Palmetto, CitraBlue, or any zoysia and avoid replanting Floratam.
Why Disease Resistance Matters More in South Florida
Most lawn fungi need three things: a susceptible host, a pathogen that’s already in the soil (and in South Florida it almost always is), and the right weather. We can’t control the pathogen, and we can’t control the weather. The grass is the one piece you get to choose.
Our weather does most of the damage. When the air temperature plus the relative humidity adds up to 150 or more, fungal activity takes off. We explain that in detail in our post on the 150 Rule for fungal outbreaks. On a typical summer afternoon in Wellington or Boynton Beach, you’ll hit that number before lunch. Then fall and spring bring the temperature swings that trigger cool-season diseases like large patch.
Put a susceptible grass in that environment and you’re signing up for a lot of work to keep it healthy. A resistant one gives you room for mistakes: a week of overwatering, a missed treatment, a rainy October.
The Diseases That Actually Matter Here
There are dozens of turf diseases, but a handful cause most of the damage we see across Palm Beach County. (For the full list with photos, see our South Florida lawn fungus identification guide.)
Large Patch (Rhizoctonia solani)
The circular brown or orange-ringed patches that show up in fall, winter, and early spring. It’s most active when soil temperatures sit between roughly 65–75°F, and it’s the number one disease problem for zoysia in Florida. St. Augustine gets it too, often under the name “brown patch.” Learn how to spot it in our large patch guide.
Gray Leaf Spot (Pyricularia grisea)
A hot-weather St. Augustine disease. Look for small gray or tan lesions with dark brown borders on the blades. It flares up in humid summer weather, especially on lawns pushed with too much quick-release nitrogen. Newly laid sod is especially vulnerable.
Take-All Root Rot (Gaeumannomyces)
A root disease that quietly thins lawns from below. It often gets mistaken for drought stress, chinch bugs, or plain old thinning St. Augustine. Wet, compacted, high-pH soils make it worse.
Sugarcane Mosaic Virus & Lethal Viral Necrosis (SCMV/LVN)
This is the big one for Palm Beach County. Sugarcane mosaic virus causes yellow streaking on the blades. In Floratam St. Augustine, it can progress to lethal viral necrosis, which kills the lawn outright. There is no cure and no treatment. The only fix is to replace the lawn with a cultivar that doesn’t develop LVN. It’s been especially active out west. See our Wellington SCMV alert.
Dollar Spot
Small, silver-dollar-to-palm-sized straw-colored spots. It’s usually a sign the lawn is hungry for nitrogen. It’s a minor nuisance on bahia, bermuda, and some zoysias, and rarely a lawn-killer.
Resistant does not mean immune. Even the best cultivars on this list can get sick if they’re overwatered, overfed, scalped, or growing in compacted soil. Resistance improves your odds; good care does the rest.
Disease Resistance at a Glance
Here’s how the cultivars we install in South Florida compare on the diseases above. Ratings are based on UF/IFAS publications and university trial data where available.
| Cultivar | Type | SCMV / LVN | Large Patch | Gray Leaf Spot | Main Watch-Out |
|---|---|---|---|---|---|
| CitraBlue | St. Augustine | Resistant | Good | Good | Chinch bugs |
| CitraZoy | Zoysia | Not a host | Excellent | N/A | Leaf spot (minor) |
| Palmetto | St. Augustine | Resistant | Fair | Fair | Fungus in humid weather, chinch bugs |
| Argentine Bahia | Bahia | Not a concern | Rarely an issue | N/A | Mole crickets, dollar spot |
| Celebration / Bimini | Bermuda | Low risk | Fair | N/A | Nematodes, dollar spot |
| Empire / JaMur / Palisades | Zoysia | Not a host | Susceptible | N/A | Large patch in fall/winter |
| Zeon | Zoysia | Not a host | Susceptible | N/A | Large patch, dollar spot |
| ProVista | St. Augustine | Limited data | Limited data | Limited data | Bred for glyphosate tolerance, not disease |
| Floratam | St. Augustine | Susceptible | Good | Susceptible | LVN, gray leaf spot, chinch bugs |
Every South Florida Cultivar, Ranked by Disease Resistance
#1 — CitraBlue St. Augustine
Best for: Homeowners who want St. Augustine’s look without constant fungicide trips.
CitraBlue was bred by UF/IFAS specifically for Florida conditions, and its disease profile is the best of any St. Augustine we install. In UF Plant Diagnostic Center evaluations, it held up to large patch about as well as Floratam (which is good at that), took less damage from gray leaf spot than other commercial cultivars, and outperformed both Floratam and Palmetto against take-all root rot.
It also matters for LVN. In test plantings on infected sites monitored by the UF/IFAS Palm Beach County Extension, LVN did not develop in CitraBlue. It’s also one of the few residential Florida turfgrasses sold through an accredited certification program, which means you’re much less likely to get contaminated sod with Floratam mixed in.
Keep in mind: Like every St. Augustine, it’s still a chinch bug target in hot, sunny spots. It also handles shade very well (see our shade tolerance rankings), and shade is where fungal pressure is usually highest.
#2 — CitraZoy Zoysia
Best for: Anyone who wants zoysia but is tired of fighting large patch every winter.
Large patch is zoysia’s biggest weakness in Florida. According to UF/IFAS’s zoysiagrass guide, large patch has never been observed on CitraZoy. That alone puts it in a different class from most zoysias on the market. Its breeder at UF has described it as having the best large patch and brown patch resistance of any zoysia currently available, while being careful to say that’s “not immunity.”
And because zoysia isn’t a host for LVN, CitraZoy is also a safe replacement for dead Floratam.
Keep in mind: It can still get leaf spot, and like any zoysia it builds thatch that should be managed. Not sure zoysia is right for you? Read St. Augustine vs. Zoysia for South Florida lawns.
#3 — Palmetto St. Augustine
Best for: Replacing Floratam on an LVN-affected property with a proven, widely available grass.
Palmetto has been the go-to LVN replacement in southeast Florida for years. It resists the progression to LVN (it can still carry the virus, but it doesn’t die from it), and it has a long track record.
What most “best grass” articles won’t tell you is that Palmetto is less resistant than Floratam to large patch and take-all root rot. UF/IFAS also notes it “sometimes has problems with disease, particularly in Florida’s humid environment.” In practice, a Palmetto lawn may need more attention to watering, mowing height, and preventive fungicide timing than a Floratam lawn did. It’s a trade-off worth making when LVN is in the neighborhood, but you should go in knowing about it.
Keep in mind: Mow Palmetto lower than Floratam (around 2.5 inches). Check our recommended mowing heights chart.
#4 — Argentine Bahia
Best for: Large, sunny, low-input properties where “tough” matters more than “lush.”
UF/IFAS puts it simply: “Few diseases cause problems in bahiagrass.” Argentine in particular is noted for good insect and disease resistance. Dollar spot shows up occasionally, and a light feeding usually lets the grass outgrow it.
Keep in mind: Bahia isn’t a manicured-lawn grass. It’s open, it throws tall seed heads all summer, and it needs full sun. Mole crickets are its main enemy.
#5 — Celebration & Bimini Bermuda
Best for: Full-sun, high-traffic yards: kids, dogs, backyard sports.
Celebration and Bimini Bermuda can get dollar spot, large patch, and leaf spot, but Bermuda’s real advantage is recovery speed. It grows so aggressively that minor disease damage often fills back in before you’d notice it on a slower grass. SCMV/LVN isn’t a meaningful concern for Bermuda lawns.
Keep in mind: According to UF/IFAS, nematodes, not fungi, are the most serious pest of Bermuda in Florida, especially on sandy soils, and no cultivar is fully resistant. Bermuda also needs full sun and more mowing. Our Bermuda care guide covers the upkeep, and Zoysia vs. Bermuda will help if you’re deciding between the two.
#6 — Empire, JaMur & Palisades Zoysia
Best for: Dense, drought-efficient lawns where you’re willing to manage large patch.
These are excellent zoysias, and like all zoysias they’re immune to LVN. Empire in particular is a proven South Florida performer. But UF/IFAS lists all three as susceptible to large patch. If you’ve had brown circles show up every November, expect them to keep showing up unless you stay on top of irrigation timing and fall preventive treatments.
Keep in mind: Don’t water in the evening, and keep nitrogen moderate in fall. Too much feeding going into cool weather is a common large patch trigger. See how nitrogen fertilizers affect fungal activity.
#7 — Zeon Zoysia
Best for: Showpiece lawns where appearance comes first.
Zeon is the finest-textured, most luxurious zoysia we install, and it’s immune to LVN. But UF/IFAS notes that fine-bladed zoysias like Zeon deal with both dollar spot and large patch. Its dense canopy holds moisture, which helps fungus get going when watering isn’t dialed in.
Keep in mind: Zeon rewards careful care: sharp blades, controlled thatch, and morning-only irrigation.
#8 — ProVista St. Augustine
Best for: Properties fighting invasive grassy weeds.
ProVista‘s claim to fame is glyphosate tolerance: you can spray Roundup over it to wipe out torpedograss, nutsedge, and bermuda encroachment without killing the lawn. It also grows slower, so you mow less. It’s a great tool for the right weed problem, but it wasn’t bred for disease resistance, and there’s much less independent university disease data on it than on CitraBlue or Palmetto.
Keep in mind: If disease is your main concern, CitraBlue or Palmetto has the stronger research behind it.
#9 — Floratam St. Augustine
Best for: Full-sun lawns in neighborhoods with no history of LVN.
Floratam is still the most-installed grass in Florida, and it isn’t all bad on disease. It actually has good resistance to large patch and take-all root rot, better than Palmetto. But three problems land it at the bottom of this list:
- LVN: Floratam is the cultivar confirmed to develop lethal viral necrosis. On an infected site, replanting Floratam risks losing the lawn all over again.
- Gray leaf spot: UF/IFAS lists it as susceptible.
- Chinch bugs: Floratam was originally released for chinch bug resistance, but chinch bugs have since overcome it and are now a major pest.
If your Floratam looks rough every winter, read why your Floratam lawn looks worse this winter before you assume it’s fungus.
Which Grass Should You Choose? Match It to Your Problem
- LVN in your neighborhood (or your lawn): Palmetto, CitraBlue, or any zoysia. Never Floratam. Our SCMV/LVN replacement guide walks through the whole process.
- Large patch every fall and winter: CitraZoy if you want zoysia, CitraBlue if you want St. Augustine.
- Shade plus humidity (the fungus trap): CitraBlue first, Palmetto second.
- Full sun, heavy traffic: Celebration Bermuda. It shrugs off damage by outgrowing it.
- Big, sunny, low-maintenance acreage: Argentine Bahia.
- Stubborn grassy weeds more than disease: ProVista.
Still weighing the bigger picture (sun, budget, look, and upkeep)? Our full guide to choosing the best sod for your South Florida lawn covers every factor, not just disease.
Even Resistant Grass Needs the Right Care
Most of the disease outbreaks we’re called out for aren’t bad luck. They’re conditions the lawn has been living in for months. Whichever cultivar you choose, these habits do the most to keep fungus away:
- Water early, deep, and less often. Irrigate between about 4 and 8 a.m. so blades dry by mid-morning, and never water in the evening. Our South Florida watering guide has the details.
- Don’t overfeed nitrogen. Heavy, fast-release nitrogen produces lush, soft growth that fungi love. Stick to slow-release sources and follow the right fertilizer timing for Florida.
- Mow at the right height with a sharp blade. Scalping and torn leaf tips both open the door to infection. Here are the best mowing practices for Florida lawns.
- Fix compaction and drainage. Standing water and airless soil feed take-all root rot. Aeration and correcting drainage problems do more than any fungicide.
- Build the soil. Healthy soil biology helps roots fight off pathogens. Look into mycorrhizal fungi and humic acid, and start with a soil test so you’re not guessing on pH.
- Clean your mower. SCMV spreads mostly on equipment. If you hire a mowing crew, ask whether they sanitize decks between properties.
- Buy certified sod. Off-type grass mixed into a pallet, like Floratam mixed into “Bitterblue,” is one of the ways LVN shows up in a lawn that was supposed to be resistant.
When a fungus does break through, treat the specific disease you have rather than spraying whatever’s on the shelf. Our guide to choosing a fungicide for St. Augustine explains which active ingredients work on which diseases.
Frequently Asked Questions
What is the most disease-resistant St. Augustine grass for Florida?
Based on UF/IFAS trial data, CitraBlue has the best overall disease profile: good resistance to large patch, gray leaf spot, and take-all root rot, and no LVN development in field trials.
Can I overseed my lawn with a disease-resistant variety?
Not with St. Augustine or zoysia. They’re sold as sod or plugs, not seed. You can plug small areas, but if disease has taken out most of the lawn, full removal and soil prep followed by new sod is usually faster and more reliable.
Do I need to remove my old grass before switching varieties?
Yes, especially if the old lawn had LVN. Any leftover Floratam can keep the virus around and compete with your new sod. More on that here: Do I need to remove my existing grass before laying new sod?
When is the best time to install new sod in South Florida?
You can install year-round here, but spring and early fall give new sod the easiest start. Winter works too. See laying sod in the winter months. Plan your budget with our 2026 sod installation cost guide.
The Bottom Line
No grass is disease-proof in South Florida, but the gap between the best and worst cultivars is big. If fungus or LVN keeps costing you money, switching to a more resistant variety is often cheaper over five years than continuing to treat the one you have. CitraBlue and CitraZoy lead the pack, Palmetto is still a solid LVN-safe choice, and Floratam is best kept to sunny yards in neighborhoods where the virus hasn’t shown up.
If you’re not sure what’s wrong with your lawn, or which grass fits your yard, we’re happy to take a look. Floridist installs certified disease-resistant sod across Palm Beach County, and our fungus control and soil-first treatment programs can help keep an existing lawn healthy. Text us a photo and we’ll point you in the right direction.