G.L. Graham and M.J. Melanson
Partner: Bleuets NB Blueberries
Abstract: Recently, growers are reporting heavier than normal sheep sorrel populations. Furthermore, the weed has moved beyond its typical bare spot
habitat and is being found more often within clones of blueberries. Typical herbicide options, such as hexazinone and propyzamide, can be quite variable in
their control levels. A trial was established in the spring in a commercial blueberry field near Aulac, New Brunswick. The trial design was a two way
factorial design, where the two treatment factors were spring and fall sprout herbicide application, with each plot receiving both a spring and fall herbicide
treatment. Significant crop injury in both June and July 2009 was observed for sulfentrazone, but the crop had recovered by the final sprout year rating.
Nicosulfuron/rimsulfuron suppressed the blueberry population. All other treatments evaluated provided a high level of blueberry tolerance. Hexazinone and
sulfentrazone alone controlled sheep sorrel in the sprout year. The addition of propyzamide to any spring herbicide treatment increased sheep sorrel control
over the first two rating periods. Hexazinone applied alone at a high rate had excellent sheep sorrel control, so an evaluation of hexazinone rates for sheep
sorrel control should occur to determine why producer applications with hexazinone have not resulted in satisfactory control.