Postemergence applications of BAS 9052 OH, {2-[1-(ethoxyimino)butyl]-5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-one}, at 0.25 and 0.5 kg ai/ha were made to 27 temperate and 28 tropical species of Gramineae. Annual bluegrass (Poa annua L. ♯3 POAAN) and rattail fescue (Festuca myuros L. ♯ VLPMY) were resistant to these rates of BAS 9052 OH. Five species of fescue and three species of bluegrass received postemergence applications of BAS 9052 OH at rates of 0.1 to 6.4 kg ai/ha. The germination of seeds and the subsequent growth of the seedlings of these species as influenced by various concentrations of BAS 9052 OH were also studied. Meadow fescue (Festuca pratensis Huds. ♯ FESPR), tall fescue (Festuca arundinacea Schreb. ♯ FESAR), Kentucky bluegrass (Poa pratensis L. ♯ POAPR), and rough-stalked meadowgrass (Poa trivialis L. ♯ POATR) were most susceptible; annual bluegrass was somewhat less resistant; hard fescue (Festuca longifolia Thuill) was resistant; red fescue (Festuca rubra L. ♯ FESRU) and rattail fescue were very resistant.
