Evaluation of Fungicides for Control of Rapid Blight of Poa trivialis (2003)

Rapid blight is a new disease of cool season turf grasses that has occurred on over a dozen golf courses in Arizona. It is now known to be caused by Labyrinthula terrestris, an organism in a group referred to as the marine slime molds. A trial was conducted in fall 2003 and winter 2004 to evaluate efficacy of selected fungicides for control of rapid blight at a golf course in central Arizona with a previous history of disease. Plots were established in late October2003 on a practice green on which Bermuda was overseeded with Poa trivialis. Treatments included Compass, Insignia, Fore, Bordeaux, Kocide 2000, Microthiol Disperss, Ecoguard and Floradox in various combinations and application dates. Disease symptoms appeared about 6 weeks after the first mowing and were evaluated in mid January. Results indicate that applications of Fore, Insignia and tank mixes of Insignia and Compass with Fore gave excellent control. Bordeaux, Compass alone, Compass alternated with Fore, Insignia alone, and Kocide gave good control. Microthiol Disperss, Floradox and Ecoguard gave poor control