Primarily a problem of bentgrass and annual bluegrass but is commonly seen in the winter on overseeded bermudagrass greens, inperennial ryegrass or rough bluegrass. Also occurs on ryegrass, tall fescues, zoysiagrass and bermudagrass. When it occurs on warm-season grasses this disease will infect in the fall as the grasses approach dormancy. Rhizoctonia cerealis remains dormant during summer and begins disease-causing activities during cool, wet weather (fall, spring, or winter) at temperatures of about 40° F. On putting greens, this disease becomes visible when tan, brown, or yellow rings appear, ranging in size from several inches to feet. On bentgrass greens, lesions are similar to brown patch that occurs in the warmer months of the year. In zoysiagrass leaf lesions, tan centers and brown borders more closely resemble dollar spot as patches. Preventative applications are needed before rings appear to control symptoms.
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