Waitea Patch

Disease

Yellow Patch, Brown Ring Patch

Waitea circinata var. circinata

Photos

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Waitea patch is an emerging problem on annual bluegrass in Michigan. Symptoms typically begin as thin yellow rings, ranging from a few inches to a 1 ft (10 cm to 0.3 m). Rings may be circular or irregular in shape, and may become brown over time. Patches often have a greenish color behind the yellow ring which tends to be soft and sunken. Symptoms are very similar to those of yellow patch, and can also be confused with fairy ring and summer patch. Unlike yellow patch however, Waitea patch tends to occur over a broader range of temperatures, and persists into the warmer weather of the summer.

The disease can first appear in the cooler weather of the spring and persist into the warm tempertuers of the summer. Infection has been shown to occur between 50° and 95° F (10° - 35° C) with optimal temperatures of 77° - 86° F (25° to 30° C). The pathogen is thought to infect the upper roots, crown, stem and leaves of individual plants. It also appears to degrade thatch, which can cause sunken rings on putting greens.

  • Crops Affected: turf

    Damage

    The location of this disease is golf courses. General symptoms are a circle, patch, and irregular coloring. Foliar symptoms are yellowing. This can occur during the months of March, April, May, June, July, August, September, and October. Hosts of the disease are Creeping Bentgrass, Annual Bluegrass, and Rough Bluegrass.

    Management

    Since Waitea patch is a relatively newly described disease in the United States, limited information with regard to cultural management practices exist. In areas where the pathogen has caused damage, adequate nitrogen fertility is recommended to allow for recovery of the turfgrass. Applications of 1 lb of nitrogen/1000ft2 (0.5 kg per 100 m2) per month has shown to significantly reduce Waitea patch severity.

    Many fungicides have shown different responses in efficacy against Waitea patch; particularly, iprodione, which is effective against other rhizoctonia-like diseases, but does NOT control Waitea patch. The fungicides flutolanil (Prostar), azoxystrobin and propiconazole (Headway), pyraclostrobin (Insignia), and fludioxonil (Medallion) have performed particularly well in field studies at MSU. Tank mixes of these with a DMI fungicide has shown to increase effectiveness in some studies as well.

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