Response of ‘Tifway’ Bermudagrass to Trinexapac-ethyl

Abstract

ABSTRACT The suppression of vegetative growth of turfgrasses can be achieved by the use of plant growth regulators (PGRs). One or two applications of trinexapac-ethyl PGR were applied at four rates to 'Tifway' bermudagrass [Cyrtodon dactylon (L.) Pers. × C. transvaalensis (Burtt-Davy)] in three studies to evaluate growth suppression and phytotoxicity. When the plant growth regulator was applied at 0.2 kg ha−1 in a single application, the vegetative growth was suppressed 30 to 34% at 2 weeks after treatment. Suppression was reduced from 17 to 24% by 4 weeks and < 12% by 6 weeks. Vegetative growth suppression at 6 weeks was higher (13 to 23%) in plots treated once with 0.4 kg ha−1 compared to those treated once at 0.2 kg ha−1 (6 to 12%). There was no advantage in vegetative suppression from split trinexapac-ethyl applications when compared to a single application when each was applied at the same total rate. The quality of 'Tifway' bermudagrass was reduced by trinexapac-ethyl applied at rates 0.2, 0.4, and 0.8 kg ha−1. Turfgrass treated at 0.2 kg ha−1 generally maintained an acceptable quality (> 90), but the turf required 3 to 8 weeks for complete recovery. Key Words: Trinexapac-ethylgrowth suppressionbermudagrassplant growth regulatorturf injury