ALABAMA A&M and AUBURN UNIVERSITIES

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contact Donna Reynolds, Extension Assistant Editor

BROWN PATCH IS BAD NEWS FOR ALABAMA LAWNS

AUBURN, APRIL 4---Brown patch is a serious disease on home lawns across Alabama. St. Augustinegrass, zoysiagrass, centipedegrass and tall fescue are the main targets for the disease, says Dr. Austin Hagan, Extension plant pathologist with the Alabama Cooperative Extension System.

Disease outbreaks are almost always tied to excessive or late use of nitrogen. Also, several days of cloudy, wet weather with temperatures between 60 and 75 degrees Fahrenheit are needed to trigger brown patch.

In the Gulf Coast counties, brown patch often appears during warm spells anytime from late fall to early spring. Further north, this disease is usually seen just before the first frosts in the fall and shortly after green-up in the spring.

Tall fescue lawns are damaged by brown spot during hot, wet summer weather.

Brown patch first appears as small brown areas a few inches in diameter. These patches quickly increase in size and merge together, forming large patches of damaged turf. On St. Augustinegrass, these patches may reach 20 feet in diameter. Damage is often worse on shaded lawns.

Good management often helps prevent outbreaks of brown patch. Apply low rates of nitrogen fertilizers monthly through the growing season. Avoid fertilizing St. Augustinegrass, zoysiagrass and centipedegrass with high rates of nitrogen shortly after spring green-up. For tall fescue, do not apply high rates of nitrogen in the summer.

To speed evaporation of dew, prune trees and shrubs to increase sunlight penetration and increase air circulation. Also, irrigate your lawn either during the early morning hours or at mid-day. In addition, verticut or dethatch your lawn to prevent the buildup of thatch.

Preventative fungicide of home lawns is usually unncessary. Routine applications should only be considered on lawns damaged by brown patch year after year. Otherwise, spot-treat damaged areas after symptoms are first seen. Make several fungicide applications to those areas ever seven to 10 days to prevent further spread of the disease.

For more information on brown patch and its control, ask your county Extension agent for circular ANR-492, "Controlling Brown Patch on Warm-Season Turfgrasses."