Pre‐snow and post‐snow applications of ethephon in winter enhance the suppression of annual bluegrass seedheads

Abstract

The practice of applying ethephon in late fall or winter to improve spring seedhead suppression of annual bluegrass (Poa annua L.) has become more common. Two distinct winter application timings were tested in eight studies on five putting greens in Utah and Colorado from 2013 to 2017. Winter ethephon treatments preceded standard spring seedhead applications and included a pre‐snow application alone (before snow cover), a post‐snow application alone (after snow melt), or a combination of both winter timings and compared to the spring programs only. Tank mixes of Civitas Turf Defense and snow mold fungicides used in the region were also tested at the winter timings. No turf injury was observed by any ethephon treatment. Winter applications of ethephon enhanced seedhead suppression in annual bluegrass, and snow mold control was unaffected. Although either single winter ethephon application would improve suppression, more suppression may be achieved by making both a pre‐snow and post‐snow application.