Page 84 - AG 7-2011 Revised 2016

BROWN PATCH Brown Patch

Brown patch is a fungal blight of cool-season grasses, which is most Photo Courtesy of Bayer
noticed during periods of hot weather. Short patches of blighted turf
will usually have a purple edge or ring appearance. Initial patches
may appear purplish-green and turn brown as the blight progresses.
On taller turf plantings, patches will appear to turn dull tan to brown.
The fungus causes lesions on leaves that may develop a reddish
brown margin. Plants killed by blight will often have a light brown
color, and turn brittle.
The most susceptible grasses for blight are bentgrass, fescue,
ryegrass, and bluegrass.

Blight is more severe under conditions of poor drainage, high
compaction, thick thatch layers, long periods of leaf wetness, low
mowing heights, excessive mechanical damage, and high nitrogen
fertilization. It is most common when temperatures are in the range of
75-95°F. Managing irrigation and leaf wetness is an important part of
controlling blight diseases.

FAIRY RING Fairy Ring

Fairy Ring is caused by a variety of species of mushroom-forming Photo Courtesy of Bayer
fungi. Fairy Rings are fairly circular and can range in size up to
several feet in diameter. They may be noticed in several forms: 1)
dark green rings with no dead turf; 2) dark green rings with a thin
ring of dying or dead turf inside or outside the green ring; 3) rings of
dying and dead turf with a hardened layer of soil that is difficult to
irrigate; and 4) rings of mushrooms without a visible effect on the turf.
Many of these mushrooms are poisonous and should not be eaten.
The fungus can be spread by spores dispersed by the mushrooms
within the rings. In some cases, rings or mushrooms can appear in
the turfgrass and cause no apparent damage. Weeds will commonly
show up in infested areas.

All grasses can be infected with Fairy Ring. Soils that have a thick
thatch layer or undecomposed organic matter favor the development
of the disease. Lawns with low fertility or insufficient water tend to
have more damage than lawns with adequate fertilizer and water.
A turfgrass management program that provides proper fertilization
and irrigation along with regular dethatching of the turfgrass will help
prevent the development of this disease. Fungicide treatment or soil
removal may be necessary if Fairy Ring becomes a regular problem.

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