Trinexapac-ethyl and Ethephon on Tifeagle
On wintergrass (Poa annua) or mixtures of wintergrass/creeping bentgrass greens, the combination of trinexapac-ethyl (Primo® MAXX) and ethephon is widely used through the western United States for suppressing seedheads of wintergrass.
Although not stated why trinexapac-ethyl and ethephon would be used on couchgrass, a recent research study (McCullough, et al., 2005) looked at the impact of trinexapac-ethyl and ethephon on "Tifeagle" couchgrass.
With repeated applications, trinexepac-ethyl reduced clippings, enhanced turf quality, and increased root mass. Trinexapac-ethyl rate used in this study was 0.04 kg ai/ha applied every 3 weeks over a 9 week period. Ethephon alone reduced root mass and turf quality, as well as causing severe thinning with increasing rate. When trinexepac-ethyl was combined with Ethephon the deleterious effects caused by ethephon alone were reduced. Although ultradwarf greens are not widespread in Australia and South Africa, interest is peaking. For example, in areas around Brisbane, Australia a few greens have been established to Tifeagle. From this study it appears that repeated treatments of trinexepac-ethyl can enhance the summer tolerance of Tifeagle by improving overall turf quality. Literature Cited 1. McCullough, P.E., L.B. BcCarty, A. Haibo Liu, and T. Whitewell. 2005. Response of "Tifeagle" bermudagrass (Cynodon dactylon x Cynodon transvaalensis) to ethephon and trinexapac-ethyl. Weed Technology 19:251-254.