G.L. Graham and M.J. Melanson
Partner: Bleuets NB Blueberries
Abstract: Sheep sorrel (Rumex acetosella) is an annual or short lived perennial weed that has been noted in blueberry
production for many years. Recently, growers are observing heavier than normal sheep sorrel populations and the weed
has moved beyond its typical bare spot habitat and is being found more often within clones of blueberries. Herbicide
options, such as propyzamide and hexazinone, can be quite variable in their control levels for sheep sorrel. A fall
herbicide application may be a viable control option, as the sheep sorrel is actively growing much later into the fall than
the blueberries. A trial was established in the fall after blueberry pruning within a commercial field near Aulac, New
Brunswick. At the time of crop harvest, no treatment resulted in significant blueberry injury, although yields were
highly variable. Complete control of sheep sorrel was not achieved for any treatment evaluated, although the high weed
pressure in the trial may have masked some treatment effects. Propyzamide had activity on sheep sorrel and would be
commercially acceptable. Sulfentrazone gave excellent sheep sorrel control at the start of the trial, but control declined
by the final ratings. Dicamba showed control at higher rates, although the most effective rate used can cause crop
injury. Triclopyr and nicosulfuron/rimsulfuron had no activity at the timing used in this trial. Significant
re–growth occurred in all treatments, demonstrating the need to evaluate multiple application timings in order to
achieve adequate, long term sheep sorrel control.
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