Seashore Paspalum Growth Regulation with Flucarbazone‐Sodium

Seashore paspalum (SP) has desirable qualities for golf course turf, but prolific seedhead production is difficult to manage with growth regulators currently available. Flucarbazone‐sodium (FS) is currently used in turfgrass seed production for weed control, but also has potential for growth regulation of tolerant species. Experiments were conducted to evaluate (i) efficacy of FS alone or with trinexapac‐ethyl (TE) for SP growth regulation, and (i) physiological behavior of FS in SP. In field experiments, FS at 30 and 60 g a.i. ha –1 3 wk –1 provided good (80–89%) to excellent (≥90%) seedhead control on 8 of 9 evaluations, but 15 g ha –1 provided poor control (<70%) on four dates. At all rates, FS alone reduced clippings 62 to 93% from nontreated at three harvest dates, and caused <20% injury. Tank‐mixtures with TE at 96 g a.i. ha –1 3 wk –1 exacerbated injury on most dates from FS at 30 and 60 g ha –1 3 wk –1 . At 96 g ha –1 3 wk –1 , TE alone reduced clippings 48 to 85% from nontreated, but only controlled seedheads 12 to 52% from 1 to 6 wk after initial treatments. In laboratory experiments, SP distributed the majority of 14 C‐FS to nontreated shoots after foliar and root uptake. The addition of TE did not affect 14 C‐FS foliar absorption at 8 hours after treatment (HAT). Seashore paspalum metabolism of 14 C‐FS in the treated leaf generally increased from ∼25% at 24 HAT to ∼50% at 168 HAT. Overall, FS has potential for managing clippings and seedheads in SP, as an alternative to TE.