Published on Thursday, 24 May 2012 18:47
Written by Filipa Mateus de Almeida
The appearance of yellow to reddish brown rings is a common springtime occurrence on golf course turf. Yellow Patch, the disease often associated with these rings can occur on creeping bentgrass (Agrostis stolonifera) and perennial ryegrass (Lolium perenne), but the symptoms are most widespread on Poa annua. The patches can range from circular to irregular or scallop shaped ranging from 50 cm to 1 meter in diameter. The yellow ring along the circumference of the patch ranges from 1 to 3 cm in width. Yellow patch, caused by the pathogen Rhizoctonia cerealis, occurs under cool (10-18C) wet cloudy conditions (3), common spring conditions in the temperate and oceanic climates. The disease is normally considered a minor problem because with the arrival of warmer sunny conditions the symptoms disappeared.
In the last few years yellow rings similar to yellow patch have occurred over a wide range of temperatures on low cut Poa annua turf with the symptoms progressively becoming more severe with increasing daytime temperatures (28-34 C). The pathogen was initially described as “Rhizoctonia-like”. Researchers at the University of California, Riverside identified the pathogen as Waitea circinata (1). Previously, researchers in Japan identified the same pathogen as causing similar symptoms on creeping bentgrass and named the disease “brown ring patch” (4).
The disease has been reported over a wide geographical range through the United States (2). On Poa annua the disease has been previously called “Waitea Patch” but it appears the accepted name is brown ring patch. Given that the disease does not disappear and increases in severity with warmer temperatures, control measures are difficult. Where the appropriate fungicides are available treatments might be warranted. A fungicide application needs to be applied in an adequate spray volume (> 2gallons/1000 sq.ft.) since the pathogen is found at the base of the plant. As a note of caution, current fungicide control strategies for this disease are not fully understood.
1. de la Cerda, K.A., Douhan, G.W., and Wong, F.P. 2007. Discovery and characterization of Waitea circinata var. circinata affecting annual bluegrass from the western United States. Plant Disease 91:791-797.
2. Rimelspach, J. 2007. They’re back … yellow rings. OSU Turf Web Site (http://buckeyeturf.osu.edu). May 29 p. 2.
3. Smiley, R.W., Dernoeden, P.H., and Clark, B.B. 2005. Compendium of turfgrass diseases. APS Press. St.Paul, MN. pp. 167.
4. Toda, T., Mushika, T. Hayakawa, T., Tanaka, A., Tani, T., and Hyakumachi, M. 2005. Brown ring patch: A new disase of bentgrass caused by Waitea circinatavar. circinata. Plant Disease 89:536-542.