Plant Growth Regulators' Effect on Growth of Mixed Cool-Season Grass Stands atFort Drum

摘要

Mowing is one of the more expensive operations in managing roadside and other low-maintenance turfgrass areas. The objective of this study was to evaluate the performance of two plant growth regulators (FGRs)-mefluidide (Embark) and imidazolinone (Event)-in reducing the development of seedheads and inhibiting the vertical growth (plant height) of mixed turf swards at multiple sites over a two-year period. Mefluidide applied at the manufacturer's recommended rate (2.3 L/ha or 2 pints/acre) provided the best general control of plant height and seedhead development compared to mefluidide at lower rates or imidazolinone at both recommended and lower rates or a combination of mefluidide and imidazolinone at lower rates. Within the control areas (no PGR), plant height did not correlate with plant weight. Therefore, the timing of treatments is critical since increases in plant height and weight occur at different times during the spring. At the early May application time, mefluidide applied at the recommended rate inhibited both plant height and weight. The effects of this treatment on plant growth were similar in most of the eight sites tested. However, PGR performance was affected by the presence of earlier maturing grasses in the sward, microclimatic factors, and broadleaf weeds. There was no difference in the effectiveness of the treatments when the materials were applied again during the following season. Despite some variation in its effect, the mefluidide treatment at the recommended rate was consistent enough among all test locations, turf species, and microclimates to recommend using this technique in the demonstration stage of the trial.