W. Kreuser, Douglas J. Soldat
Sep 1, 2011
Citations
2
Influential Citations
25
Citations
Journal
Crop Science
Abstract
Trinexapac-ethyl (TE) is a widely used growth regulator in the turfgrass industry. Poor summer effi cacy has been related to more rapid metabo- lism in the plant. The purpose of this study was to determine if a growing degree day (GDD) model could be used to identify the optimum TE reappli- cation interval for putting greens. This objective was accomplished through model development and validation. Model development was con- ducted on a creeping bentgrass (Agrostis stolon- ifera L.) golf putting green in Madison, WI, during 2008. The treatments consisted of fi ve TE reap- plication intervals (100, 200, 400, 800 GDD, and 4 wk) and a control. Growing degree days were calculated in degrees C with a base temperature of 0°C. Trinexapac-ethyl was applied at the rate of 0.05 kg a.i. ha -1 . Clippings were collected daily. The 100- and 200-GDD reapplication intervals provided consistent 20 and 12% yield suppres- sion, respectively. Other reapplication intervals had alternating periods of yield reduction fol- lowed by yield enhancement. Model valida- tion occurred on a different creeping bentgrass green in 2009 and 2010. The experiment was a 3 × 2 factorial CRD with three TE rates (0.00, 0.05, and 0.10 kg a.i. ha -1 ) and two reapplication frequencies (200 GDD and 4 wk). The 200-GDD interval consistently suppressed clipping yield. Application rate had no effect on the duration of suppression. Reapplying TE every 200 GDD pro- vides more consistent growth regulation than a calendar-based application schedule.