Response of Kentucky Bluegrass to Four Growth Retardants

Abstract

Abstract A turfgrass blend of ‘Parade’, ‘Adelphi’, ‘Glade’, and ‘Rugby’ Kentucky bluegrasses ( Poa pratensis L.) was treated with N-[2,4-dimethyl-5-[[(trifluromethyl) sulfonyl] phenyl] acetamide (mefluidide) at 0.28 and 0.56 kg ha −1 ; (2-chloroethyl) phosphonic acid (ethephon) at 2.24, 4.48, and 6.72 kg ha −1 ; 5-(4-chlorophenyl)-3,4,5,9,10-pentaaza-tetracyclo [5,4,1,0 2,6 ,0 8,11 ]dodeca-3,9-diene (BAS 106 00 W) at 1.68, 3.36, and 5.04 kg ha −1 , and α-(1-methylethyl)-α-[4-(trifluromethoxy) phenyl]-5-pyrimidinemethanol (EL-500) at 0.84, 1.21, and 1.40 kg ha −1 in field and greenhouse studies. Each of the materials investigated was effective in retarding Kentucky bluegrass growth in field studies. However, effects on growth inhibition and turfgrass quality varied between years. Ethephon was the only material not effective in reducing clipping yield in the greenhouse, whereas none of the growth retardants inhibited root organic matter production or rhizome weight in the greenhouse study.