Brown patch

src: ag.umass.edu

Brown Patch is a turfgrass disease caused by Rhizoctonia species. This turfgrass disease is the most common chocolate patch to be found in all winter turfgrass found in the United States. The most damaging chocolate patches: Bentgrass (Agrostis sp.), Ryegrass (Lolium sp.), Annual Bluegrass (Poa annua), and Tall fescue (Festuca arundinacea). Chocolate filling is also found in Kentucky bluegrass (Poa pratensis) and Fine fescue (Festuca sp.) But this is rare or only slight damage. Chocolate patch is known as leaf disease, so it has no effect on the crown or the roots of grass plants.

Video Brown patch

Symptoms

The symptoms of chocolate patches differ depending on the various maintenance practices performed on turfgrass (cutting altitude, fertilizer, watering, etc.) Symptoms on wet turfgrass for long periods and trimmed closely will produce a grayish ring typical of a grayish " which is up to 50 cm in diameter, while the tall, non-wet grass for a long time will start producing patches of several feet in diameter and may have a "frogeye" appearance.The white mycelium can be found in dewy grass early in the morning. take a closer look at the leaves of the grass leaf (usually on the High Fescue) You might see chocolate become a small irregularly shaped lesion.

Maps Brown patch

Disease Cycle

Rhizoctonia species thrive in temperatures ranging from 70 ° F to 90 ° F but can survive in freezing temperatures. Chocolate patches are most common when night temperatures fail to fall below 68 Â ° F and during periods of high humidity or prolonged wet leaves. Rhizoctonia species have two specific fungi that affect grass plants at different times throughout the year. In most cases, Rhizoctonia solani will cause the Brown patch in June throughout early July. As the temperature begins to heat up and the air becomes more humid, Rhizoctonia solani will become Rhizoctonia zeae. It has been found that brown patches thrive on fertile and succulent turfgrass that have high nitrogen levels compared with moderate-run grasses. It has been found that Rhizoctonia species are able to survive on the ground for years without affecting turfgrass. During the winter months, the fungus will fall asleep on the grass or ground tissue and form into a resting body called sclerotia.

src: ag.umass.edu

Cultural Control

Similar to most turfgrass diseases one of the best cultural practices to prevent Brown patches is to incorporate new resistant turfgrass varieties. To find this new cultivar, you can visit the seed distributor of turfgrass, an extension specialist, or visit the National Turfgrass Evaluation Program website at: [www.ntep.org]. If combining resistant varieties of turfgrass is not an option then focus on better management practices. Some management practices include reducing reeds, having adequate drainage, and removing moisture during hot and humid weather. Dew can be removed from the grass from the cut, using a backpack blower, or dragging the hose across the grass. Install an internal drainage system if you have severe drainage problems. Improve air circulation and avoid irrigation practices that will leave moisture in the grass for a long time. Adequate aeration programs will reduce compaction and improve drainage. Aeration annually should interfere between 15-20% of the total surface area. Make sure you do not use excess nitrogen to your soil. The most balanced fertility program for Kentucky Bluegrass grass will consist of the application of 2-5 lbs nitrogen/1000 sq.ft. year.

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Chemical Control

If it is severe enough or on expensive summer grass patches (eg green golf) can be controlled with the use of fungicides. The application of fungicide is usually done curatively. Apply the fungicide on the first sign of the Brown patch symptoms. In a bad traditional area that causes severe damage to the grass, the application of fungicide prevention will work best. Fungicides should be applied in accordance with the instructions on the label, fungicidal applications containing thiophanate-methyl and/or chlorothalonyl in weather above 90 ° F have been shown to be ineffective against Rhizoctonia zeae. Minimize the cost of fungicide application by selecting fungicdes that will work on a variety of turfgrass diseases at the same time.

Effective fungicides include:

• Benzimidazoles: Pro Turf
• Carboxide: Prostar
• DMI: Banner, Bayleton
• Dicarboximides: Proturf Fungicide X, Touche
• Dithiocarbamates: Captan
• Nitriles: Daconil
• QoIs: Heritage, Compass, Insignia
• Antibiotics: Supports (polyoxin D)
• Phenylpyrroles: Medallion

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References

Source of the article : Wikipedia