Seashore Paspalum Response to Trinexapac-ethyl and Paclobutrazol

The usage of seashore paspalum ( Paspalum vaginatum Swartz) as a recreational turf has increased in recent years. On similar species, such as bermudagrass ( Cynodon ssp.), plant growth regulators (PGRs) are used to decrease mowing frequency. However, no data currently exists for the use of PGRs on seashore paspalum. Therefore, field experiments were conducted over 2 years to determine the effects of trinexapac-ethyl and paclobutrazol on seashore paspalum. Paclobutrazol was non-injurious to turf when applied sequentially, 4 weeks apart, at rates as high as 0.56 kg·ha -1 of a.i. However, these same treatments failed to reduce vegetative growth. Conversely, trinexapac-ethyl treatments produced unacceptable injury (>15%) when applied sequentially, 4 weeks apart, at rates higher than 0.19 kg·ha -1 of a.i. As trinexapac-ethyl rates were reduced to ≤0.14 kg·ha -1 of a.i., injury was reduced to ≤ 12% while vegetative growth was suppressed to ≥59%, relative to nontreated seashore paspalum. Therefore, trinexapac-ethyl can serve as an effective option for those managing seashore paspalum turf areas. Chemical names used: 4-(Cyclopropyl-α-hydroxymethylene)-3,5-dioxo-cyclohexanecarboxylic acid ethyl ester (trinexapac-ethyl); (+/-)- R * , R * -β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1 H -1,2,4-triazol-1-ethanol (paclobutrazol).