Published online by Cambridge University Press: 12 June 2017
A red fescue (Festuca rubra L.)- Kentucky bluegrass (Poa pratensis L.) turf was treated annually with amidochlor {N-[(acetylamino)methyl]-2-chloro-N-(2,6-diethylphenyl)acetamide} at 2.2, 2.8, and 3.4 kg ai/ha, mefluidide {N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl] amino] phenyl] acetamide} at 0.4 kg ai/ha, and ethephon [(2-chloroethyl) phosphonic acid] at 5.6 kg ai/ha for three consecutive years. Recuperative potential of treated turfgrass was determined in the field and in a greenhouse study. Amidochlor and mefluidide treatments injured turfgrass (11 to 64%) four weeks after application. However, turfgrass recovered after eight weeks. Amidochlor at 2.8 to 3.4 kg/ha and mefluidide at 0.4 kg/ha suppressed (75 to 100%) seedhead development. Ethephon at 5.6 kg/ha was ineffective. Turfgrass recovered normally each spring after amidochlor treatments, with no delay in spring green-up. Root length, root weight, and root:shoot weight ratio of the plugs from the greenhouse study were unaffected by three consecutive annual applications of amidochlor, mefluidide, and ethephon. One annual spring application of amidochlor, mefluidide, and ethephon for three consecutive years caused no adverse effects that would limit their use on red fescue-Kentucky bluegrass turf.