Turfgrass Tolerance and Weed Control with Methazole and Metribuzin

Methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] and metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one] were evaluated in separate experiments for postemergence control of large crabgrass [Digitaria sanguinalis(L.) Scop.] and goosegrass [Eleusine indica(L.) Gaertn.] and on tolerance of centipedegrass [Eremochloa ophiuroides(Munro) Hack.], St. Augustinegrass [Stenotaphrum secundatum(Walt.) Kuntze], and bermudagrass [Cynodon dactylon(L.) Pers. ‘Common’]. Methazole was also evaluated on tolerance of Kentucky bluegrass (Poa pratensisL. ‘Common’). Metribuzin applied at 0.6 kg/ha and methazole at 1.1 kg/ha as single treatments controlled 82 and 87% goosegrass, respectively. Repeated treatments were needed for similar control of large crabgrass. These treatments did not permanently injure bermudagrass or centipedegrass. St. Augustinegrass was severely injured when treated with single applications of methazole at 1.1 kg/ha or metribuzin at 0.6 kg/ha while Kentucky bluegrass was severely injured by methazole applied at any rate. Methazole caused moderate to severe injury to bermudagrass when applied at 2.2 kg/ha in each of two applications and to centipedegrass when applied at 4.4 kg/ha in each of two applications.