---
title: "Large patch on zoysia, St. Augustine, and centipede—fall–spring Rhizoctonia vs summer brown patch"
description: "Warm-season large patch (Rhizoctonia solani AG 2-2 LP): circular yellow/orange patches at fall and spring green-up, leaf-sheath lesions, soil-temperature timing (~70 °F fall), why it is not cool-season summer brown patch, culture-first nitrogen and moisture habits, and honest fungicide framing for DIY lawns."
pubDate: 2026-07-20
updatedDate: 2026-07-21
canonical: "https://lawncarejournal.app/articles/large-patch-zoysia-st-augustine-centipede/"
---

If your **zoysia**, **St. Augustine**, or **centipede** lawn shows **circular yellow-to-orange patches** that enlarge year after year—especially as the grass is **going dormant in fall** or **greening up in spring**—you may be looking at **large patch**, not the midsummer “brown patch” story that hits tall fescue. NC State, UGA, and Clemson Extension all describe the same homeowner-relevant disease: a **cool, wet weather** problem on **warm-season** turf caused by *Rhizoctonia solani* **AG 2-2 LP**—a different strain from the *R. solani* AG that drives [summer brown patch on cool-season lawns](/articles/summer-brown-patch-rhizoctonia-tall-fescue).

This guide is an identification and expectations framework for a typical DIY warm-season lawn—not a remote diagnosis. Confirm chronic patches with [county extension](https://www.extension.org/) before renovating or buying every “lawn fungicide” on the shelf. For the late-summer **soil-temperature checklist**, nitrogen stop dates, and preventive spray framing, use the companion [fall large patch timing checklist](/articles/fall-large-patch-fungicide-timing-zoysia-warm-season). Mixed cool- and warm-season lots should also read the [brown patch → large patch season flip](/articles/transition-zone-brown-patch-large-patch-season-flip).

## Key takeaways

- **Large patch** = warm-season disease (zoysia, St. Augustine, centipede, bermuda, seashore paspalum); most damaging on **centipede**, then zoysia / St. Augustine; **bermuda** often outgrows it (NC State, Clemson, UGA themes).
- Caused by *Rhizoctonia solani* **AG 2-2 LP**—not the same anastomosis group as cool-season summer brown patch (UGA C1088).
- Active when thatch/soil cools into roughly the **50–70 °F** window with prolonged moisture; symptoms peak in **cool, wet fall and spring**, often most obvious at **spring green-up** (NC State, UGA).
- Look for **circular patches** from about **1 ft to many feet** across, bright **yellow/orange** margins, and **water-soaked reddish-brown or black lesions on leaf sheaths**—roots are usually not the primary kill story the way [take-all root rot](/articles/centipedegrass-decline-take-all-root-rot) is.
- DIY wins: **hold early-spring and late-season nitrogen**, improve drainage and thatch, irrigate deeply but infrequently in the morning, mow at species-appropriate heights—not another soft “green-up” dump into cool wet weather.
- Fungicides are **preventive** and **fall-timed** (zoysia often near **~70 °F** for 5+ days; centipede/St. Augustine often earlier near **~80 °F** per NC State)—see the [fall timing checklist](/articles/fall-large-patch-fungicide-timing-zoysia-warm-season); many retail products are weak matches—read the label for **large patch** / warm-season turf.

## Side-by-side: large patch vs common look-alikes

| Clue | Large patch | Summer brown patch (cool-season) | Take-all / centipede decline | Chinch bugs |
| --- | --- | --- | --- | --- |
| Season | **Fall & spring** (cool + wet); can linger into mild winters | **Hot humid summer** nights | Summer thinning; spring fail-to-green | Hot sunny midsummer |
| Hosts | Warm-season (zoysia, St. Aug, centipede…) | Tall fescue, ryegrass, etc. | Centipede & other warm-season roots | Often St. Augustine |
| Pattern | Circular patches **1–26+ ft**; yellow/orange edge | Smoke-ring foliar blight | Irregular yellow → thin; **black roots** | Wilt in sun; insects under canopy |
| Tissue | **Leaf sheath** lesions; tip dieback | Leaf/sheath foliar blight | **Root** rot | Roots usually intact |
| N cue | Excess **fall/early-spring** N worsens | Excess **midsummer** N worsens | Excess annual N on centipede | Fertility secondary |
| Start here | This guide | [Brown patch](/articles/summer-brown-patch-rhizoctonia-tall-fescue) | [Centipede decline / take-all](/articles/centipedegrass-decline-take-all-root-rot) | [Chinch & armyworms](/articles/chinch-bugs-armyworms-warm-season-lawn-damage) |

Also compare [dollarweed in wet spots](/articles/dollarweed-pennywort-warm-season-lawn-identification-control), [ground pearls](/articles/ground-pearls-centipedegrass-lawn-identification) (expanding yellow circles with sand-to-pearl cysts), [dormant vs dead](/articles/dormant-grass-vs-dead-grass-summer) winter browning, and spring green-up habits in [zoysia / St. Augustine spring care](/articles/zoysia-st-augustine-spring-green-up-mowing).

## What you are looking at

UGA describes circular patches from roughly **3 to 26 feet** across. Freshly infected turf at the **periphery** often looks bright **yellow and/or orange**. Centers thin, sink, and invite weeds; patches can be **perennial**, returning and expanding in the same spots. Pull blades at the active margin: infection sits on the **lower leaf sheaths** as water-soaked, reddish-brown, or black lesions; foliar dieback then runs from tip toward the base. NC State’s symptom set emphasizes sheath lesions and tan/yellow/orange/red foliar color—**not** a primary root-and-crown rot profile.

That sheath story is why large patch is easy to confuse with “dead grass from winter” at green-up and with midsummer insect wilt later. Dig before you assume: soft black roots point toward [take-all](/articles/centipedegrass-decline-take-all-root-rot); carpet-lift C-shaped larvae point toward [white grubs](/articles/white-grub-japanese-beetle-lawn-midsummer-control); flotation insects under St. Augustine blades point toward [chinch bugs](/articles/chinch-bugs-armyworms-warm-season-lawn-damage).

## Why it is not “brown patch in July”

Homeowners and older labels still say “brown patch” for everything *Rhizoctonia*. NC State renamed the warm-season disease **large patch** because it differs in **hosts**, **season**, **symptoms**, **fungal anastomosis group**, and **control timing**. Cool-season brown patch thrives in **hot days and warm nights** with long leaf wetness on tall fescue and ryegrass. Large patch thrives when warm-season grasses are **slow**—entering or exiting dormancy—under **cool, wet** thatch and soil.

Practical takeaway: a July smoke-ring on tall fescue and an October orange ring on zoysia are **not** the same DIY playbook, even if both involve *Rhizoctonia*.

## Weather and soil window

- **Infection window (UGA):** thatch temperatures about **50–70 °F** with continuous moisture for **at least ~48 hours**.
- **Fall start (NC State / Clemson themes):** pathogen activity often begins as soil temperatures decline toward about **70 °F**; symptoms may lag until cool wet stretches or spring green-up.
- **Favoring factors:** excess nitrogen in fall and early spring, poor drainage, over-irrigation, heavy thatch, low mowing heights, shade, and restricted airflow (NC State, Clemson, UGA).

A [soil thermometer](https://www.amazon.com/s?k=soil+thermometer+garden&tag=lawnjournal0c-20) helps you watch the fall cool-down and spring warm-up instead of guessing from the calendar. Catch-can inches from a [rain gauge](https://www.amazon.com/s?k=lawn+rain+gauge&tag=lawnjournal0c-20) keep you from stacking irrigation on top of rainy cool weeks. As an Amazon Associate, Lawn Care Journal LLC earns from qualifying purchases.

## What DIY culture can accomplish

You cannot stop a cool rainy spring, but you can stop stacking soft growth and wet thatch on top of it.

**Hold late-season and early-spring nitrogen.** NC State’s cultural framing: do not apply nitrogen to warm-season grasses within about **6 weeks before dormancy** in fall or within about **3 weeks after green-up** begins in spring—those grasses are growing slowly and do not need a soft push then. Clemson’s South Carolina homeowner calendar is even more concrete for that state: avoid nitrogen after about **August 15** (Upstate/mid-state) or **September 1** (coast), including many “winterizer” bags that still contain N. UGA ties spring N to soil warmth (about **65 °F at 4 in. and rising** in their Georgia framing) rather than the first warm Saturday. Pair decisions with a [soil test](/articles/spring-soil-test-before-lawn-fertilizer) and species budgets in [zoysia / St. Augustine spring care](/articles/zoysia-st-augustine-spring-green-up-mowing) and [bermuda green-up](/articles/bermuda-grass-spring-green-up-when-to-fertilize).

**Manage moisture, not mist.** Irrigate **deeply and infrequently**, preferably early morning, and only as needed to prevent severe drought in fall and spring (NC State / UGA). Chronic surface wetness favors large patch and [dollarweed](/articles/dollarweed-pennywort-warm-season-lawn-identification-control). Verify inches with [rain gauge / soil probe habits](/articles/lawn-rain-gauge-soil-probe-measure-watering) and check [smart controller / rain sensor](/articles/smart-irrigation-controller-rain-sensor-verification) shutoff before another automatic cycle.

**Improve drainage, thatch, and air.** Core-aerate and cultivate in **summer** when warm-season turf is growing strongly—avoid spreading inoculum with aggressive cultivation while the pathogen is most active in cool spring/fall windows. Raise mowing height within species norms; UGA notes large patch on zoysia worsens as height drops from about **1.5 in. toward 0.5 in.** Prune shrubs that trap humidity. Spot compaction at gates still matters—see [spot compaction](/articles/spot-compaction-paths-gates-high-traffic).

**Species expectations.** Centipede and seashore paspalum often take the hardest hits; zoysia and St. Augustine can stay thin for weeks to months; bermuda frequently recovers faster once heat returns (NC State, Clemson). Chronic centipede failure after high-N programs also belongs in the [decline / take-all](/articles/centipedegrass-decline-take-all-root-rot) conversation—dig roots before you pick a jug.

## Fungicides—preventive, fall-first, label-first

UGA’s homeowner framing is blunt: **few highly effective retail options**, so culture and species choice lead. Where fungicides are used, extension programs emphasize **prevention**, not rescue after half the lawn is orange.

Timing themes across NC State and Clemson:

- **Fall applications matter most**—often initiated when soil/thatch temperatures settle near about **70 °F** for several consecutive days (exact trigger and product list vary by state bulletin).
- NC State notes earlier starts for some grasses (centipede / St. Augustine sometimes discussed when soils first decline toward the **80 °F** range for consecutive days) and zoysia closer to the **70 °F** fall trigger—follow your **state** bulletin, not a national blog date.
- A **spring** application near green-up is often discussed for chronic sites.
- Apply in enough water (NC State cites on the order of **≥2 gal per 1,000 sq ft**, sometimes with light watering-in) so product reaches sheaths and thatch—not a mist on leaf tips.

Many professional actives are **not labeled for home lawns**. If you still choose a retail product, confirm **large patch** (or *Rhizoctonia* on warm-season turf) is listed, match grass species and re-entry, and rotate modes of action when labels require it—see [pets after treatments](/articles/pet-safe-lawn-care-after-fertilizer-herbicide). Optional search when a labeled product is appropriate: [lawn fungicide large patch](https://www.amazon.com/s?k=lawn+fungicide+large+patch+zoysia&tag=lawnjournal0c-20). Prefer reading the active-ingredient panel over packaging photos. As an Amazon Associate, Lawn Care Journal LLC earns from qualifying purchases.

## Expectations worth writing down

Large patch is a **seasonal amplifier**: cool wet thatch + slow warm-season growth + soft nitrogen. Culture reduces frequency and severity; it rarely erases a low wet bowl overnight. Distinguishing fall/spring orange rings on zoysia from midsummer [brown patch on fescue](/articles/summer-brown-patch-rhizoctonia-tall-fescue), [take-all black roots](/articles/centipedegrass-decline-take-all-root-rot), and [chinch wilt](/articles/chinch-bugs-armyworms-warm-season-lawn-damage) is the scientifically honest first step—and it keeps you from fighting the wrong season with the wrong product.

## What to journal this week

Log soil temperature at 2–4 in., rainfall vs irrigation inches, patch photos (yellow/orange margins?), leaf-sheath lesion checks, last nitrogen date and product, mowing height, and whether the same circles returned from last spring. Map chronic patches now so fall preventive timing is targeted instead of whole-lawn guesswork. [Lawn Care Journal](/) for iPhone and iPad is built for those notes; download on the [App Store](https://apps.apple.com/us/app/lawn-care-journal/id1507797403). Optional in-app Assistant is educational only—not a disease diagnosis.

Related reads: [transition-zone brown patch → large patch season flip](/articles/transition-zone-brown-patch-large-patch-season-flip), [fall large patch timing checklist](/articles/fall-large-patch-fungicide-timing-zoysia-warm-season), [St. Augustine gray leaf spot](/articles/gray-leaf-spot-st-augustine-late-summer) (sticky midsummer leaf spots—not cool-wet large patch), [spring dead spot fall timing (bermuda)](/articles/spring-dead-spot-bermudagrass-fall-fungicide-timing), [zoysia / St. Augustine spring care](/articles/zoysia-st-augustine-spring-green-up-mowing), [summer brown patch (cool-season)](/articles/summer-brown-patch-rhizoctonia-tall-fescue), [tall fescue brown patch recovery](/articles/tall-fescue-brown-patch-recovery-september-overseed), [centipede decline / take-all](/articles/centipedegrass-decline-take-all-root-rot), [chinch bugs & armyworms](/articles/chinch-bugs-armyworms-warm-season-lawn-damage), [dollarweed](/articles/dollarweed-pennywort-warm-season-lawn-identification-control), [ground pearls](/articles/ground-pearls-centipedegrass-lawn-identification), [summer watering](/articles/summer-lawn-watering-deep-infrequent), [rain gauge / soil probe](/articles/lawn-rain-gauge-soil-probe-measure-watering), [smart controller / rain sensor](/articles/smart-irrigation-controller-rain-sensor-verification), [soil testing](/articles/spring-soil-test-before-lawn-fertilizer), [bermuda spring green-up](/articles/bermuda-grass-spring-green-up-when-to-fertilize), [dormant vs dead](/articles/dormant-grass-vs-dead-grass-summer). More DIY topics: [articles index](/articles). App help: [Support](/support).