Evaluation of Proxy and Primo for Growth Reduction in Perennial Ryegrass

Abstract

PROXY (ethephon) and PRIMO (trinexepac-ethyl) were applied to ryegrass (as overseeded turf) in winter and early spring of 1999. PGR effect was assessed as reduction in clipping weight between mowings on eleven harvest dates. From March to April, the greatest percentage reductions were realized from all PGR treatments. Over the entire test period (March 5 to May 15), clipping reduction was rate dependent for PROXY with the 10.0 ounce rate producing a greater PGR effect (less clippings than that of PROXY at the 5.0 ounce rate). PRIMO treated turf (at the highest label rate of 1.0 ounce/product/1000 ft) generally produced the greatest clipping reductions, but lost affect in the middle of May when suppression (broke) was released. PROXY at the 10.0 ounce rate was closer to that of PRIMO for PGR effect than was PROXY at the 5.0 rate. All treatments produced less clippings than that of the control on nine of the eleven harvest events. PRIMO produced on average a noticeably darker color turf than PROXY treated turfs and that of the control plots as well. PROXY treated turf at the 10.0 ounce rate generally had similar overall quality turf when compared to PRIMO treated turf throughout the test. This was due to a high degree of plant uniformity among PROXY treated turf, versus the darker color enhancement realized from PRIMO. No PGR affected the initial stages of spring transition from ryegrass to bermuda by late May 1999.