Combinations Of Rolling, Mineral Oil, Sulfur, And Phosphorous Acid Affect Microdochium Patch Severity

Microdochium patch is a turfgrass disease that occurs in cool, humid regions caused by the fungal pathogen Microdochium nivale (Fr.) Samuels & Hallett [Teleomorph = Monographella nivalis (Schaffnit) E. Mull]. Fungicide applications are the predominant method of control; however, pesticide restrictions have generated concern regarding the use of traditional chemicals to manage turfgrass pests. The objective of this research was to evaluate the effects of the cultural practice of rolling in combination with applications of mineral oil, S, and/or phosphorous acid (H3PO3) on the suppression of Microdochium patch on an annual bluegrass (Poa annua L.) putting green. A 2-yr field trial took place from September 2013 to June 2014 and was repeated from September 2014 to June 2015 on a sand-based annual bluegrass putting green in Corvallis, OR. Experimental design was a 2 x 4 x 2 x 2 randomized complete split-plot design with four replications. Factors included rolling, the fertility products S and H3PO3 applied alone and in combination, mineral oil treatment, and year. Mineral oil suppressed Microdochium patch although applications led to turfgrass thinning. The combination of S and H3PO3 provided greater Microdochium patch disease suppression compared to applying either alone. Rolling also suppressed Microdochium patch in the second year of this study. Further research to determine how to best utilize these combined cultural practices to manage Microdochium patch is warranted.