Disease During Bermuda Dormancy: How Spring Dead Spot Gets Started in Winter

Here’s the cruelest trick spring dead spot pulls on DFW homeowners: it attacks in fall and winter, hides all season long, and then reveals the damage in April or May when your bermudagrass finally wakes back up. By the time you see those ugly sunken circles on your lawn, it’s already too late to treat for this year. The pathogen did its dirty work months ago — while your lawn was dormant, while you weren’t watching, while you assumed everything was fine.

Spring dead spot is the most destructive bermudagrass disease in North Texas. It’s also the most misunderstood, because the timing between infection and visible damage is so far apart that most homeowners never connect the dots. At Hamann Lawn Care & Weed Control, we’ve been treating Arlington and DFW yards since 2006, and spring dead spot is one of the most common calls we get every spring from homeowners who swear their irrigation is broken, their bermuda was winter-killed, or they have a grub problem. Usually, it’s none of those things. It’s a root-rot pathogen that moved in during October and quietly destroyed crowns and stolons all winter.

What Spring Dead Spot Actually Is

Spring dead spot is caused by soilborne fungi in the genus Ophiosphaerella — primarily Ophiosphaerella korrae, O. herpotricha, and O. narmari, depending on your region. In Texas, O. korrae and O. herpotricha are the main culprits. These pathogens are root and crown rotters. They don’t attack leaves or blades — they go straight for the vascular tissue below ground, rotting roots, crowns, and stolons until the grass is completely dead from the inside out.

The infection cycle starts in fall, typically September through November in the DFW area, as soil temperatures cool into the 50s and 60s. Bermudagrass is going into dormancy, its metabolism is slowing, and its natural disease defenses are dropping. That’s when Ophiosphaerella moves aggressively. It colonizes root and crown tissue, producing dark, necrotic rot that spreads through the root zone over the entire winter. The grass sits dormant looking completely normal on the surface while the pathogen is systematically destroying what holds it alive underground.

Then April hits. DFW warms up. Your bermuda gets the signal to break dormancy. The healthy areas green right up. But the spots where Ophiosphaerella did its work? Nothing. Dead. Sunken. Straw-colored circles that stay brown while everything around them turns green. That’s spring dead spot revealing itself.

The Bermuda Paradox: Most Vulnerable When It Looks Fine

This is the part that trips up most homeowners. Bermudagrass looks absolutely bulletproof in July and August. It’s thick, green, and aggressive. It’s crowding out weeds and spreading into every corner of your yard. That mid-summer strength creates a false sense of security — the lawn looks so healthy that the idea of a fungal disease taking hold seems absurd.

But spring dead spot doesn’t attack in summer. It attacks at transition — specifically when bermuda is going INTO dormancy in fall and when it’s coming OUT of dormancy in late winter and early spring. Those transition windows, roughly September through November and again February through March in DFW, are when the pathogen is most active and when bermuda is most susceptible. Soil temperatures during those windows are in the sweet spot for Ophiosphaerella: not cold enough to suppress the pathogen, but cool enough that bermuda’s defenses are down.

That early-spring window — February and March — is a secondary infection period. The pathogen can continue spreading even as bermuda starts showing the first signs of break from dormancy. This is important because it means the disease window isn’t just fall. If you miss fall treatment, there’s still a narrow window in late winter before things get visibly bad.

What the Spots Look Like in Spring

Spring dead spot shows up as distinct, roughly circular patches of dead straw-colored grass. The spots tend to be sunken or slightly depressed compared to the surrounding healthy turf — that’s because the root mass underneath has rotted away, causing the surface to collapse slightly. Size ranges from about six inches for new infections all the way to three feet or more for established infestations that have been building for multiple years.

One of the most telling signs is the ring of weeds that colonizes the dead zone. Dandelions, annual bluegrass, clover, and other opportunists move into the dead spots almost immediately because there’s no competition. You’ll often see a circular patch that’s weedy in the center while healthy bermuda surrounds it. Over summer, bermuda does try to fill in from the edges — stolons creep inward toward the dead zone. But that fill-in process is slow and incomplete, especially on larger spots. And if the pathogen population in the soil isn’t treated, it returns and re-infects the following fall, making the spots larger each year.

If you’re not sure whether you’re looking at spring dead spot or something else, our full lawn disease and fungus controlguide walks through how to distinguish spring dead spot from winter kill, grub damage, and irrigation failure — three things homeowners commonly confuse it with.

DFW-Specific Risk Factors That Make It Worse

Not every bermuda lawn gets spring dead spot, and not every lawn gets it equally bad. Several factors specific to North Texas increase your risk significantly.

Heavy clay soils.DFW is famous for Blackland Prairie clay, and it’s exactly the kind of soil spring dead spot loves. Clay holds moisture longer, stays cooler deeper, and creates the anaerobic conditions near root zones where Ophiosphaerella thrives. If your yard drains poorly or you have areas where water pools after rain, those spots are prime spring dead spot territory.

Thatch buildup. A thick thatch layer acts as a reservoir for the pathogen. Ophiosphaerella lives in organic matter, and thatch gives it a protected environment close to the root zone. Lawns with thatch layers over half an inch have dramatically higher spring dead spot pressure than well-maintained yards.

High nitrogen fertilization in late summer. This is one of the most common mistakes Arlington homeowners make, and it directly fuels spring dead spot. Applying a heavy nitrogen fertilizer in August or September pushes bermuda into a flush of lush, soft growth right before it needs to be hardening off for winter. That soft new growth is especially susceptible to Ophiosphaerella infection. It also delays dormancy, extending the window of vulnerability.

Soil pH problems. Bermuda performs best at a soil pH of 6.0 to 7.0. DFW soils often trend alkaline, and high pH reduces the availability of certain micronutrients that support plant immunity. Lawns with pH issues have less natural disease resistance and tend to develop more severe spring dead spot symptoms.

The Recurrence Problem: Why Untreated Spring Dead Spot Gets Worse

This is the detail that matters most for long-term lawn health. Spring dead spot is not a one-and-done problem. When left untreated, the Ophiosphaerella population builds in the soil year over year. Small spots expand. New spots develop. What was a scattering of six-inch circles in year one can become overlapping two- and three-foot patches by year three or four. We’ve seen Arlington yards where twenty to thirty percent of the bermuda lawn was consumed by spring dead spot over the course of a few untreated seasons. By that point, recovery requires significant soil work in addition to fungicide treatment.

The earlier you identify and treat spring dead spot, the easier it is to manage. Catching it in its first or second year — when spots are still small and the pathogen population is lower — gives fungicides a much better chance of bringing the disease under control.

If you’ve also noticed other winter-period disease symptoms on your lawn, winter lawn disease in North Texas covers the broader range of problems that can hit dormant grass, including some that overlap with and compound spring dead spot damage.

Treatment Timing: When Fungicide Actually Works

Here’s the hard truth about spring dead spot treatment: by the time you see circular dead spots in April or May, this season’s damage is already done. Applying fungicide to visible spring dead spot spots in spring will not reverse the damage. What it can do is reduce the pathogen load going into summer and start protecting the lawn against the fall infection cycle.

Effective spring dead spot management requires preventive fungicide applications timed to the infection windows. In DFW, the primary window is fall — September and October, when soil temperatures are dropping into the 60s and the pathogen is becoming active. Fungicide applications during this window penetrate to the root zone and interrupt the infection before it gets established. A secondary application in late winter (February through early March) can address the spring infection window, especially on lawns with a known spring dead spot history.

The fungicides used for spring dead spot are systemic — they need to move down to root level to work. Proper application rate, timing, and watering-in after application all matter significantly. This is not a disease where a basic granular fungicide from the hardware store is going to cut it.

What NOT to Do

Several common lawn care practices significantly increase spring dead spot risk, and most of them are things homeowners do with the best intentions.

Skip the late-summer nitrogen push.Fertilizing heavily in August or early September feels productive — the grass looks great for a few weeks. But that flush of growth right before dormancy creates exactly the soft, susceptible tissue that Ophiosphaerella targets. Stop nitrogen applications by late July in DFW.

Don’t overwater in fall. As bermuda slows down and temperatures drop, cut back irrigation significantly. Keeping the soil wet in fall extends the favorable conditions for the pathogen and delays the dormancy hardening process.

Don’t ignore thatch. If your lawn has a thick mat of dead organic material above the soil surface, it needs to be addressed. Dethatching or core aeration in late summer helps reduce the habitat that harbors Ophiosphaerella and improves fungicide penetration.

The Integrated Approach That Actually Works

Controlling spring dead spot long-term isn’t just about spraying fungicide once. It requires a coordinated program: fall fungicide applications at the right soil temperature window, proper fall fertilization timing that supports root development without pushing vulnerable top growth, thatch management to reduce pathogen habitat and improve treatment penetration, and soil pH testing to make sure your bermuda has the micronutrient availability it needs to fight back. On clay-heavy DFW soils, core aeration in late summer is especially valuable — it improves drainage, reduces compaction, and helps fungicide reach the root zone where it needs to work.

At Hamann Lawn Care & Weed Control, we’ve been managing spring dead spot on Arlington and DFW bermuda lawns since 2006. We know the soil types, we know the timing, and we know how to put together a treatment program that interrupts the disease cycle before it does visible damage. If you saw circles last spring, fall is the time to act — not next April.