Field studies were conducted in wild blueberry in 2007 and 2008 to evaluate the efficacy of hexazinone applied PRE and multiple application timings of POST mesotrione on goldenrods and the efficacy of burning, terbacil applied PRE, nicosulfuron/rimsulfuron applied POST, and multiple application timings of mesotrione applied POST on black bulrush. Mesotrione application timings were at 10 and 30 cm of height, floral bud initiation, and full flower. Hexazinone applied at 1.92 kg ha−1 in 200 L water ha−1 effectively suppressed goldenrods. At least 90% goldenrod damage was achieved with mesotrione POST applied at 101 g ha−1 in 300 L water ha−1 before full flower, following hexazinone PRE at two of three sites. Damage following mesotrione was more variable when hexazinone was not applied. Mesotrione efficacy was lower when applied in the crop year, but a crop-year registration may be warranted to improve harvest ease and increase berry quality. A single application of mesotrione at the label rate did not adequately control black bulrush. Ninety percent black bulrush control was achieved with rimsulfuron/nicosulfuron applied at a rate of 0.03 g L−1 of water with 0.2% v/v nonionic surfactant. Equivalent levels of control were achieved with sequential mesotrione applications at the label rate.
Nomenclature: Hexazinone; mesotrione; nicosulfuron; rimsulfuron; terbacil; goldenrods, Solidago spp.; black bulrush, Scirpus atrovirens Willd; wild blueberry, Vaccinium angustifolium Ait.