Crown-rot anthracnose, caused by Colletotrichum cereale, remains the most important disease of the past decade on golf course greens. This is because of the demand by golfers for ‘fast greens,’ which is accomplished by lowering the mowing height and reducing the nitrogen fertility. These two factors exacerbate CRA and have helped make it a significant disease on annual bluegrass (i.e. Poa annua) in the past decade.
Controlling CRA is also becoming a problem because of C. cereale becoming resistant to thiophanate-methyl and quinone outside inhibitor (QoI) fungicides. For years, this author has tried to convince golf course superintendents to use one class of fungicides until resistance develops, but this recommendation has mostly been drowned out by many voices urging superintendents not to forget to practice good fungicide resistance management by rotating different chemistries. This idea was supposed to work by one class of chemistry “getting rid of resistant strains that developed to a different class of chemistry,” and it might have worked if the fungus could have only become resistant to one class of chemistry at a time.
Read the full article: Controlling Turfgrass Diseases