5 Common Bermudagrass Diseases

Bermudagrass disease - Hydraulic fluid injury

You love your bermudagrass lawn for its high foot traffic tolerance and drought resistance. It may invade the flower beds from time to time, but fortunately, that means you have an aggressive grower that outcompetes weeds. But despite being a powerhouse in the yard, your turf is vulnerable to five common bermudagrass diseases.  

Ready to protect your beloved bermudagrass from diseases? We’ll show you how to identify and treat each fungal disease. 

1. Large patch

Causal agent: Rhizoctonia solani  (This pathogen also causes brown patch and yellow patch disease).

Symptoms: Disease symptoms occur in early spring when grasses green up and conditions are wet. Rough circular patches of brown or yellow grass appear in the yard, ranging from a few inches to several feet in diameter. In some cases, these patches may merge. 

The patch’s center may turn green as the lawn recovers, creating a donut shape. 

Upon closer inspection, you may discover rotted, water-soaked leaf sheaths near the soil surface (sheaths are where the leaf blades attach to the stem). 

Conditions for disease: 

  • Prolonged periods of wetness (can be caused by poor drainage, wet weather, overwatering, or watering in the evenings)
  • High humidity 
  • Applying nitrogen fertilizer to warm-season grasses (like bermudagrass) in late summer when it’s too close to autumn
  • Excessive thatch
  • The disease may be more severe if the soil pH is below 6.0

Treatment: The best way to manage large patch disease in your bermudagrass lawn is to practice good lawn care. The good news is that bermudagrass recovers quickly from large patch thanks to its aggressive growth habits. 

  • Water early in the morning. The best time to water the lawn is before 10 a.m., preferably before 8 a.m. Watering in the evenings is no good because the water clings to the grass overnight and creates a moist environment. 
  • Water less often. Watering infrequently and for long periods encourages a deep root system. It also gives the lawn a chance to dry between waterings. Watering too often and for short periods promotes a shallow root system and doesn’t allow enough time for the turf to dry. 
  • Set the mower to the proper mowing height. Mowing too low can increase large patch’s severity, and mowing too high encourages leaf wetness. The ideal mowing height for common bermudagrass is 1 to 2 inches and ½ to 1 ½ inches for hybrid varieties.
  • Relieve soil compaction with core aeration
  • Remove excessive thatch with a dethatcher
  • Perform a soil test to determine the soil pH. You may need to apply lime to raise the pH between 6.0 and 7.0. 
  • Fungicides are more reliable as a preventative treatment than a curative treatment. Apply fungicides to warm-season lawns in fall to prevent symptoms from appearing in spring. According to the Clemson Cooperative Extension, the fungicides azoxystrobin (with propiconazole), pyraclostrobin (with triticonazole), and fluoxastrobin provide excellent large patch management. 
Dollar spot on Bermudagrass
Dollar Spot | Scot Nelson | Flickr | Public domain

2. Dollar spot

Causal agent: Clarireedia jacksonii (formerly Sclerotinia homoeocarpa)

Symptoms: If your bermudagrass lawn looks like a bermudagrass dalmatian, it might be suffering from dollar spot disease. Symptoms appear as tan spots 2 to 6 inches in diameter peppered across the lawn. The spots are typically the size of a silver dollar (surprise, surprise), appearing in late spring or early summer. 

Infected grass blades have bleached, hourglass-shaped lesions with brownish-purple borders. In the mornings, the turf may exhibit a cobweb-like, silvery coating called mycelium. 

When dollar spot is severe, the individual spots may merge to create large affected areas. 

Conditions for disease: Lawns with dry soils and low nitrogen levels are vulnerable to dollar spot. 

Treatments:

  • Perform a soil test and apply the recommended amount of nitrogen.
  • Remove thatch buildup.
  • Mow the grass regularly.
  • Correct your irrigation regime. Water deeply and less often to promote a robust and healthy root system. 
  • Fungicides for dollar spot control are available. However, they work best as a preventative measure combined with good lawn care. The disease can quickly develop a resistance to fungicides, so it’s good to alternate between products. Fungicides for dollar spot include boscalid, myclobutanil, propiconazole, thiophanate-methyl, triadimefon, triticonazole, and vinclozolin.
Leaf spot
Leaf spot | Scot Nelson | Flickr | Public domain

3. Leaf spot and melting out

Causal agent: Drechslera poae causes leaf spot, and Bipolaris sorokiniana causes melting out. 

Symptoms: Once considered a single disease, leaf spot and melting out are two turfgrass diseases that often occur together. 

Leaf spot symptoms first appear as tiny purplish-black dots on the grass blades. The dots gradually grow into elliptical lesions with purplish-black borders and tan tissue in the center. Some spots may be surrounded by yellowing tissue. 

The melting out disease is the more serious of the two. The disease progresses down into the crown and roots, rotting away the leaf sheaths, rhizomes, and stolons. 

Conditions for disease:

  • In bermudagrasses, most damage occurs in fall and spring when conditions are cool and wet, especially during long periods of cloud cover.  
  • Excessive thatch
  • Shaded areas with poor air circulation
  • Deficient or excessive nitrogen
  • Low mowing heights
  • Drought
  • Long periods of leaf wetness

Treatments: 

  • Perform a soil test and apply the recommended amount of nitrogen during the turf’s growing season. 
  • Practice watering techniques that minimize prolonged leaf wetness. 
  • Trim or prune vegetation in shady areas to increase air circulation. 
  • Mow regularly. 
  • Remove excessive thatch. 
  • According to the PennState extension, fungicides containing chlorothalonil, iprodione, mancozeb, penthiopyrad, azoxystrobin, or fludioxonil typically provide good leaf spot control. They work best when applied as a preventative measure or in the early stages of the disease. Fungicide applications are unlikely to cure melting out. 
Rust on lemongrass
Rust | Scot Nelson | Flickr | Public domain

4. Rust

Causal agents: Different fungi cause different rust diseases. The fungus most responsible for rust in bermudagrass, particularly in bermudagrass fields, is Puccinia cynodontis. 

Symptoms: If a stroll through your bermudagrass leaves your shoes and socks covered in reddish-brown dust, your turf may have rust. Here’s how you know: 

  • The lawn or field looks bronze from a distance.
  • Tiny dark brown to orange pustules appear on the grass blades. These pustules rise slightly above the grass blade’s surface. 
  • The pustules burst and release dusty reddish-brown spore masses. 

Conditions for disease: 

Treatments: 

  • Maintain proper soil fertility.
  • Remove excessive thatch.
  • Practice good irrigation techniques that minimize leaf wetness.
  • Harvest the grass for hay or graze heavily.
  • Fungicides are available for rust control. However, you must read and follow all application instructions. Fungicides may not be suitable if your bermudagrass field has livestock. 

5. Spring dead spot

Causal agents: Spring dead spot in bermudagrass is caused by one or more species of Ophiosphaerella. 

Symptoms: If circular patches of bleached dead grass appear in your spring bermudagrass lawn, it may signify spring dead spot disease. These patches range between 6 inches and several feet in diameter. The fungal disease also rots the roots, rhizomes, and stolons. 

The fungus itself doesn’t cause the bleached grass, but rather, it makes the grass sensitive to winter damage. So the colder and wetter the winter, the worse the damage appears in spring. 

The patches can grow in size year after year if left uncontrolled. The patches may develop a donut-shaped pattern as weeds or re-established bermudagrass take over the center. 

Conditions for disease:  

  • The fungus is most active when soil temperatures are between 50 degrees and 70 degrees Fahrenheit. 
  • High nitrogen levels.
  • Applying nitrogen fertilizer to warm-season turf too close to the fall season.
  • According to the Clemson Cooperative Extension, soil pH above 6.2 has been linked to spring dead spot. 
  • Excessive thatch and soil compaction may reduce the turf’s cold hardiness.

Treatments: 

  • Aerate and dethatch the lawn in summer. Don’t perform these tasks when the disease is active; otherwise, the fungus might spread. 
  • Test soil and create a balanced fertilizer regime.
  • Apply fungicides in the fall, about one month before the lawn goes dormant. Fungicides for spring dead spot control include propiconazole, myclobutanil, and thiophanate-methyl. 

FAQ about bermudagrass diseases

How do I know if my bermudagrass has fungus?

When your lawn fades from green to brown, that doesn’t necessarily mean there’s a fungus problem. Drought stress, heat stress, or dormancy might be the cause. But if your lawn exhibits the following, then there may be a fungus attacking your lawn: 

• Patterns or patches of discolored turf appear in the yard.
• Unusual growth develops between the turf blades, such as fuzzy mycelium.
• Individual grass blades develop discolored patterns on the leaf tissue.
• Parts of the turf plant are rotten, such as the roots, stolons, rhizomes, and sheaths. 
• Visible mushrooms grow on the lawn. 

How can I protect my bermudagrass lawn from fungal disease?

The best way to protect your bermudagrass lawn from fungal disease is to practice good lawn care. Bad watering habits, weak root zones, and unbalanced soil fertility create an attractive environment for fungus to thrive. 

Applying fungicides to prevent disease development is another way to defend your lawn, but you don’t want to replace good lawn care with fungicides. Fungicides can only do so much, and using fewer fungicides is better for the environment. The healthier your lawn, the less likely it will succumb to diseases and the less you’ll need to rely on fungicides. 

Another option is to reseed or resod with a bermudagrass cultivar resistant to various diseases. Keep in mind that disease resistance varies among cultivars. 

What if I can’t identify the fungus on my lawn?

Some fungal diseases are difficult to identify because they mimic the symptoms of other diseases. But to treat the disease successfully, you need to identify it correctly. Otherwise, your control measures might prove futile. 

If you can’t identify the disease, contact a diagnostics lab or a turfgrass pathology lab (your local state university might have one). These labs specialize in accurately diagnosing turfgrass disease. 

How do I test my soil to treat fungal disease?

Several turfgrass diseases must be corrected with improved fertilization and soil amendments. To determine the best fertilizers and amendments for your lawn’s soil, send a soil sample to your local university or cooperative extension office for laboratory testing. 

DIY at-home soil tests are available, however, they don’t provide as detailed results as laboratory soil tests. A laboratory soil test provides the best recommendation for your lawn based on its soil type and grass type. 

Hire a pro and say “Bye, bye, fungi”

You worked hard all week so you could enjoy a relaxing weekend. Are you really going to let a lawn fungus take away those precious hours from you? Instead of sweating in the sun and bending over your bermudagrass, hire a local lawn care professional to revive your lawn’s health and green color. While a pro fights off the fungal infestation, enjoy your weekend fungus-free. 

Main photo credit: Scot Nelson | Flicker | Public domain

Jane Purnell

Jane Purnell is a freelance writer and actor in New York City. She earned her B.A. from the University of Virginia and enjoys a warm cup of French press coffee.