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LAWN & TREE » Turf & Tree Insects  Plant & Grass Diseases Fire Ant Treatments |
Plant & Grass Diseases
Brown Patch
 The beauty of a lawn can be quickly destroyed by brown patch (Rhizoctonia species), a serious fungal disease that can affect all Texas
lawn grasses. It can develop rapidly when temperatures are warm (75 to 90 °F) and humid, especially on cool-season grasses (fescue,
ryegrass, bluegrass and bentgrass). It can also occur on these grasses during warmer periods of the winter months. Warm-season grasses
(St. Augustinegrass, zoysiagrass, Bermudagrass and centipedegrass) most commonly are affected by brown patch (also called large patch)
during the early spring and late fall.
The best way to prevent brown patch in the home lawn is by following good lawn care practices. This is much easier and less expensive
than the use of fungicides and can be very effective.
Avoid high rates of nitrogen fertilizer on cool season grasses in the late spring and summer. Avoid high nitrogen rates on warm season grasses in mid to late fall. The brown patch fungus readily attacks the lush growth of grass which nitrogen promotes.
Irrigate grass only when needed and to a depth of 4 to 6 inches. Water early in the morning. This disease can spread fast when free moisture is present.
Avoid spreading the disease to other areas. Remove clippings if the weather is warm and moist to prevent spread to other areas during mowing.
Keep lawns mowed on a regular basis to the proper height for the grass species you are growing. Prevent excessive thatch buildup.
Provide good drainage for both surface and subsurface areas.
Fungicides can be difficult to rely upon for controlling brown patch in the home lawn but regular applications can vastly improve
appearance. A good "rule of thumb" to follow on either cool- or warm-season grasses is to initiate fungicide sprays when night time low
temperatures reach 70 °F. Stop applications when night time lows are forecast to be below 70 °F for five consecutive days. Typically,
applications are made at 14-day intervals. If disease is severe enough to warrant chemical control, select one of the following fungicides
listed in Table 1. It may help in control to alternate fungicides used with subsequent applications to prevent a buildup of resistance to
a fungicide. Slightly better control may be obtained by a liquid fungicide application rather than by granular application.
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