Raghuwinder Singh, Ferrin, Donald M.
Large patch is the most common disease of warm-season turfgrasses in Louisiana. This disease is caused by the soilborne fungus Rhizoctonia solani. Although large patch is particularly prevalent on St. Augustine grass (see Figures 1-3) it also occurs on all other warm-season turfgrasses, such as Bermuda grass, centipede grass and zoysia. As the name suggests, the disease is characterized by the development of large, circular or irregularly shaped patches of diseased turf that can become quite extensive if not treated. The large patch fungus does not usually kill the grass but rather causes a rot at the bases of the leaf sheaths that makes the leaves separate readily from the crown of the plant. The result is thinned areas of turf that are readily invaded by weeds. For St. Augustine grass, the turf at the leading edge of the patch that is being attacked by the pathogen typically exhibits a yellowish cast, whereas for centipede grass it exhibits a reddish cast.
The LSU AgCenter and the LSU College of Agriculture