This study was conducted to determine if the rate of ‘Meyer’ zoysiagrass (Zoysia japonica Steud.) establishment and spread could be enhanced when plugs were introduced into plant growth regulator-(PGR) treated Kentucky bluegrass (Poa pratensis L.) and perennial ryegrass (Lolium perenne L.) turfs. During the first growing season, PGR treatment made little difference in zoysiagrass spread. Zoysiagrass coverage in perennial ryegrass treated with mefluidide (57%) or amidochlor (63%) was significantly greater than in ryegrass treated with ethephon (47%) or the untreated control (48%) by the end of the 2nd year. Enhanced zoysiagrass spread in perennial ryegrass treated with mefluidide and amidochlor was attributed to stand thinning resulting from PGR phytotoxicity and environmental stress in the first year. Zoysiagrass coverage in Kentucky bluegrass was greatest in mefluidide-treated plots, but the increase over the control was only 6%. Flurprimidol slowed the establishment of zoysiagrass in both cool season turfs. Chemical names used: [(N-[(acetylamino)methyl]-2-chloro-N-(2,6-diethyl phenyl)acetamide (amidochlor); (2-chloroethyl)phosphonic acid (ethephon); α-(l-methylethyl)-α-[4-(trifluoromethoxy)phenyl]-5-pyrimidinemethanol (flurprimidol); and N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]amino]phenyl]acetamide (mefluidide).
Received for publication 25 Feb. 1985. Contribution from the Agronomy Dept., Univ. of Maryland as Scientific Paper No. A-4078 and Contribution No. 7063 of the Maryland Agriculture Experiment Station, College Park, MD 20742. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.