Controlling Brown Patch on Warm- Season …

1 Controlling Brown Patch on warm - Season Turfgrasses in Home LawnsBrown Patch is the most damaging disease of warmseasonturfgrasses in Alabama. St. Augustinegrass, zoysiagrass, andcentipedegrass are most susceptible to this disease; commonand hybrid bermudagrasses are rarely nitrogen fertility levels and thatch often lead tooutbreaks of Brown Patch . The disease usually develops onlawns during periods of wet, overcast weather in late springor fall. Damage is often heaviest after several days of show-ers with day temperatures of 60 to 80 F and heavy humid coastal areas, Brown Patch is usually found fromlate fall through early spring on St. Augustinegrass and cen-tipedegrass lawns during extended periods of mild, cloudy,wet Patch first appears in lawns as small, circular, Brown areas several inches in diameter, which quickly in-creases to 3 to 6 feet (Figure 1).

2 These areas often grow to-gether, forming irregular patches of Brown , blighted turf upto 20 feet in diameter (Figure 2).The foliage of high-cut St. Augustinegrass or centipede-grass turf often wilts and collapses, giving the blighted Patch -es a sunken appearance. Damaged turf usually recoverswhen conditions no longer favor the spread of of the turf may start in the center of the blightedarea, forming a ring or frogeye pattern. Weeds frequently in-vade turf damaged by Brown to individual grass plants is usually confined tothe foliage. Leaves and leaf sheaths attacked by the brownpatch fungus, Rhizoctonia solani,first become water-soaked,then wilt, and finally turn Brown . On broadleafed turfgrasseslike St. Augustinegrass, distinct tan-colored leaf spots sur-rounded by a water-soaked margin are sometimes seen.

3 Ifthe crowns of individual plants or stolons are invaded, largeareas of a lawn may be MeasuresNitrogen fertility has a significant impact on Brown patchdevelopment. High nitrogen levels promote the growth ofsoft, succulent leaves that are susceptible to attack by thebrown Patch help prevent disease outbreaks, apply a low rate of anitrogen fertilizer at 4- to 8-week intervals through the grow-ing Season , or use a slow-release nitrogen source to maintainan even growth Patch on zoysiagrass (top) and (bottom)Figure favorable conditions, damaged areas growtogether to form large, irregular patches of blighted reduce the risk of disease outbreaks during the winterand early spring, avoid fall and late winter applications ofhigh rates of nitrogen fertilizer.

4 Finally, maintain phospho-rus and potash fertility levels according to soil test A&M AND AUBURN UNIVERSITIESV isit our Web site also plays an important role in disease develop-ment. Good drainage is needed to remove excess water fromlow-lying areas. To speed evaporation of water from the fo-liage, prune nearby trees and shrubs to reduce shade and im-prove air movement and sunlight penetration. Also, irrigatelawns at midday to minimize the time that the foliage re-mains harbors the Brown Patch fungus. Periodic mechan-ical dethatching or core aerification is needed to preventthatch buildup, especially on high-maintenance and zoysiagrass of Brown Patch are usually too sporadic, espe-cially on home lawns, to justify a preventive fungicide sprayprogram.

5 Limit preventive treatments to portions of thoselawns that have previously been damaged by this applications only when weather conditions favor thespread of disease. The time interval between applicationsvaries between 10 and 21 days, depending on the most home lawns, a fungicide spray program shouldbegin as soon as symptoms appear and continue until theturf starts to recover or until weather conditions no longerfavor the spread of disease. For best results, apply fungicidesat 5- to 7-day intervals to the diseased area and to a 1- to 2-foot Table 1 for a list of fungicides recommended forbrown Patch control on warm - Season turfgrasses on homelawns. A complete listing of fungicides can be found inExtension publication ANR-530, Disease and Insect Controlfor Commercial Turf.

6 Table Registered for Brown Patch ControlAmount To UseProductPer 1,000 Sq. fl. at 7- to 14-day intervals in 2 to 5 gal. of water per 1,000sq. ft. Shorten intervals and tank-mix with Daconil 2787 or Forewhen disease is 26019 to 2 oz. (9 to 13 T.)Apply at 14- to 28-day intervals in 2 to 10 gal. of water per 1,000sq. ft. Under severe conditions, shorten spray intervals and increase T/O4 at 7-day intervals in 3 to 5 gal. of water per 1,000 sq. 80W4 MAXX2 to 4 fl. in 2 to 5 gal. of water per 1,000 sq. ft. before symptoms are seen. Repeat at 14- to 28-day intervals. DO NOT apply more than 4 fl. oz. per 1,000 sq. ft. in a 30-day period to fl. needed, retreat every 10 s oz. (4 to 8 T.)Apply when disease symptoms first appear, and continue at 5- toCleary s 3336F1 to 2 fl.

7 Intervals as needed. Shorten spray interval and increase rateFungo FLO1 to 2 fl. disease is T/O1 to 2 oz. (6 to 12 T.)Apply at 15- to 30-day intervals in 2 to 4 gal. of water per 1,000sq. ft. when weather patterns favor disease development. Shorteninterval and increase rate when disease symptoms K. Hagan,Extension Plant Pathologist, Professor, Plant Pathology, Auburn UniversityUse pesticides onlyaccording to the directions on the label. Follow all directions, precautions, and restrictions that are list-ed. Do not use pesticides on plants that are not listed on the pesticide rates in this publication are recommended onlyif they are registered with the Environmental ProtectionAgency and the Alabama Department of Agriculture and Industries.

8 If a registration is changed or cancelled, the rate listedhere is no longer recommended. Before you apply any pesticide, check with your county Extension agent for the latest names are used onlyto give specific information. The Alabama Cooperative Extension System does not endorse orguarantee any product and does not recommend one product instead of another that might be more information,call your county Extension office. Look in your telephone directory under your county s name tofind the in furtherance of Cooperative Extension work in agriculture and home economics, Acts of May 8 and June 30, 1914, andother related acts, in cooperation with the Department of Agriculture. The Alabama Cooperative Extension System(Alabama A&M University and Auburn University) offers educational programs, materials, and equal opportunity employmentto all people without regard to race, color, national origin, religion, sex, age, veteran status, or , 10M13, Revised March 1999,ANR-492