Effect of Irrigation Frequency and Fertilization Application Method On Silvery Thread Moss Encroachment in Creeping Bentgrass.

Silvery-thread moss (STM) encroachment into cool season golf greens on a variety of rootzone materials is prevalent throughout the world.  Silvery-thread moss invasion compromises a healthy, dense turfgrass, leading to an inconsistency of ball roll and rebound resilience.  Two studies were conducted to test the hypothesis that delivering resources at the surface as opposed to the rootzone may increase the population of STM in creeping bentgrass turfgrass.  The first study examined the relationship between irrigation frequency and rate on the establishment of STM within a “Penn A4” creeping bentgrass canopy. Greenhouse experiments were conducted where creeping bentgrass pots were uniformly inoculated with 1 g of moss followed by the initiation of an irrigation program consisting of two rates, 75% and 100% evapotranspiration_, at frequencies of 1, 2, 4 and 7 days. The results showed that higher amount of STM was present in the 1 and 2 day application frequencies than in the 4 and 7 day frequencies regardless of watering rate.  A second experiment was conducted where urea was applied with three different application methods: foliar liquid, watered-in liquid, and granular.  Foliar fertilization had significantly more STM (46% cover) than the watered-in liquid (39%) and granular (35%) treatments.  These greenhouse experiments confirm that surface application of water through frequent irrigation and urea-based nitrogen through foliar fertilization resulted in an increased presence of inoculated STM in creeping bentgrass stands.