Response of Goosegrass Biotypes Protoporphyrinogen Oxidase Inhibitors.

Goosegrass (Eleusine indica) is a problematic weed in both warm and cool season turf. With limited post emergence (POST) control options, control is difficult. Greenhouse studies were conducted to determine response of seven goosegrass ecotypes (‘Craft Farms’, ‘GGCCV’, ‘GGRB’, ‘Tennessee Valley’, ‘Texas’, ‘W’, ‘Woodward’) to protoporphyrinogen oxidase inhibitors. Oxadiazon (Ronstar), flumioxazin (Sureguard), and sulfentrazone (Dismiss) were evaluated for postemergence goosegrass control of two to three tiller plants at various rates. The herbicides were applied with using a CO2 pressurized R&D handheld boom sprayer. The sprayer utilized a 1.5 m wide boom with three Spraying System TeeJet 8002 VS nozzles. The study was replicated 3 times. Ratings were taken at 3 days, 7 days, and 4 weeks. At 7 days after the initial treatment Sulfentrazone and flumioxazin applied at 0.14 kg/ha controlled 81 to 96 % of the goosegrass respectively. Two ecotypes of goosegrass were found to be resistant to one protoporphyrinogen oxidase inhibitor but not to the other three herbicides from the same chemical group. These two ecotypes of goosegrass were not affected by oxadiazon at 2.24 kg ai/ha while a susceptible ecotype was controlled at 0.56 kg/ha. Across all treatments, on average, sulfentrazone and flumioxazin had 81 and 96 % control rate of two to three tiller goosegrass plants respectively. Oxadiazon was significantly less in control at 52 %. Additional research should be conducted to determine if flumioxazin can be safened on actively growing bermudagrass for goosegrass control.