ZOYSIAGRASS ESTABLISHMENT FROM SPRIGS FOLLOWING APPLICATION OF HERBICIDES, NITROGEN, AND A BIOSTIMULATOR

Sprigs of 'Meyer' zoysiagrass (Zoysia japonica Steud.) were treated wi th urea nitrogen, a biostimulator, and one of three preemergence herbi cides or one of two postemergence herbicides to hasten establishment i n two field studies. Monthly application of N at 48 kg . ha(-1) during the growing season had no influence on sprig establishment the first gear, but slightly increased (+5%) zoysiagrass cover the second year. Presoaking sprigs in a solution containing (mg . L(-1)) 173 auxin and 81 cytokinin, and iron at 1.25 g . L-(1) before broadcasting of sprigs , and biweekly sprays (g . ha(-1)) of 53 auxin and 24 cytokinin, and i ron at 0.2 g . L(-1) or (g . ha(-1)) 68 auxin and 36 cytokinin, and ir on at 1.45 g . L(-1) after broadcasting sprigs had no effect on zoysia grass cover or rooting. Preemergence and postemergence herbicide use g enerally enhanced zoysiagrass cover by reducing smooth crabgrass compe tition [Digitaria ischaemum (Schreb. ex Schweig) Schreb. ex Muhl]. Oxa diazon enhanced zoysiagrass coverage more than dithiopyr, pendimethali n, quinclorac, or fenoxaprop. Oxadiazon and dithiopyr provided similar levels of crabgrass control, but dithiopyr reduced 'Meyer' zoysiagras s midsummer root growth. Chemical names used: 3,5-pyridinedicarbothioi c acid, romethyl]-4-[2-methyl-propyl]-6-(trifluoromethyl)- SS-dimethyl ester (dithiopyr); [+/-]-ethyl 2-[4-[(6-chloro-2-benzoxazolyl)oxy]phe noxy] propanoate (fenoxaprop); o-5-(1-methylethoxy)phenyl]-5-(1,1-dime thylethyl)- 1,3,4-oxadiazol-2-(3H)-one (oxadiazon); 1-ethylpropyl)-3,4 -dimethyl-2,6-dinitrobenzenamine (pendimethalin); 3,7-dichloro-8-quin- olinecarboxylic acid (quinclorac).