Brown ring patch

[1] The disease primarily affects putting greens and causes yellow or brown rings up to 1 metre (3.3 ft) in diameter.

[4][6] Brown ring patch is similar to other Rhizoctonia species, but appears to infect upper roots, crowns, and stems as well as foliage of individual plants.

[5][failed verification] Brown ring patch is most destructive when the weather is humid and temperatures are stressful to the grass.

Conversely, in warm-season grasses such as zoysia, Brown ring patch is most severe in humid weather with moderate temperatures (45–70 °F or 7–21 °C).

[11] The disease is more severe on greens which have low nitrogen fertility and often develops first on areas that are dry or have other environmental stresses.

Research in 2008 demonstrated that 1 pound of nitrogen per 1,000 sq ft (nitrate, ammonium or urea) could reduce disease by 50 percent or more.

[12] Cultural skills include reducing thatch aggressively by verticutting and/or aerifying in the spring and fall when the turf is actively growing, and raise the mowing height prior to and during summer stress periods.

The best treatment is to apply Medallion, polyoxin-D (e.g., Affirm and Endorse), ProStar, one of the QoI fungicides (e.g., Heritage or Insignia), Trinity, Triton Flo, and Torque now and repeat in two to three weeks to limit disease development later in the spring.