Spring disappointment with dead spring spot

Spring disappointment with dead spring spot

Photo: Mike Kenna, Ph.D.

Spring dead spot SDS is a devastating disease of bermudagrass but rarely harms zoysia or buffalograss. This fungal disease can cause significant damage and economic losses to golf courses if not controlled.

The name stems from its characteristic symptom, circular patches of dead or dormant grass that appear in the spring when Bermuda grass begins its active growth phase. These spots are typically 6 inches to 3 feet in diameter and are most noticeable in cold areas with long winter conditions.

This disease is caused by three types of: Ophiospherellawith Ophiospherella herbotrichia Being the most common and aggressive pathogen. The fungus overwinters in infected plant debris and straw, and becomes active as temperatures rise in the spring. Spread occurs primarily through the movement of infected plants or infected soil via equipment, people, animals, and running water.

The pathogen attacks the roots and rhizomes, causing their necrosis and impairing the plant's ability to absorb water and nutrients. When grass breaks dormancy, the result is the formation of dead patches, which can persist throughout spring and into early summer.

Symptoms of spring dead spot (SDS) on bermudagrass: a) whitish color of dead plants, b) presence of severe SDS in the golf course fairway, c) less severe circular and arc patterns of SDS in the golf course fairway, and d) dead bermudagrass is a plant with Black roots, crown, roots and stones.  (Photo: Nathan Waller, Ph.D., Oklahoma State University, EPP-7665)

Symptoms of spring dead spot (SDS) on bermudagrass: a) whitish color of dead plants, b) presence of severe SDS in the golf course fairway, c) less severe circular and arc patterns of SDS in the golf course fairway, and d) dead bermudagrass is a plant with Black roots, crown, roots and stones. (Photo: Nathan Waller, Ph.D., Oklahoma State University, EPP-7665)

There are several factors that contribute to the development of SDS. The disease is more serious in poorly drained soils with high thatch accumulations. Compacted soil, inappropriate irrigation, and lack of proper cultural practices can also exacerbate the problem.

SDS management involves an integrated approach. Cultural practices such as proper mowing, proper irrigation, and avoiding excessive nitrogen fertilization are essential to maintaining a healthy Bermudagrass stand. Aerating the soil to reduce compaction and promote good drainage can also be beneficial. Newer bermudagrass cultivars selected for improved cold tolerance and SDS resistance are less susceptible to infection.

Fungicide applications are critical in controlling SDS. Experts recommend using fungicides preventatively during the fall and early spring to protect turf from infection and reduce the impact of the disease. Fungicides containing active ingredients such as azoxystrobin, propiconazole or thiophanate methyl have been shown to be effective.

Understanding the causes of SDS and implementing sound management practices, including cultural techniques and fungicide applications, is critical in disease prevention and control.

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