Fungicidal control options for silvery thread moss on creeping bentgrass putting greens

Abstract Silvery thread moss ( Bryum argenteum Hedw.) (STM) is a common weed on golf course putting greens. Limited herbicidal options are available for the control of STM. Previous research suggests that certain contact fungicides may have efficacy against STM; therefore, a study was conducted to explore fungicidal options for managing STM on golf course putting greens. The study was conducted in Fayetteville, AR, on a “Pure Eclipse” and “Ninety‐Six Two” creeping bentgrass ( Agrostis stolonifera L.) green. Every combination of the fungicides chlorothalonil, fluazinam, mancozeb, and thiram was tested, along with carfentrazone‐ethyl, an industry‐standard herbicide, and a nontreated control for a total of 17 treatments. Treatments including chlorothalonil were the most effective at reducing STM coverage, while the combination of fluazinam + mancozeb + thiram was moderately effective at controlling STM. In a supplemental study conducted in Blacksburg, VA, chlorothalonil greatly reduced moss coverage, while potassium phosphite and fosetyl‐Al were ineffective. These results give turfgrass managers an alternative to carfentrazone‐ethyl for managing silvery thread moss on their putting greens.