G.L. Graham and M.J. Melanson
Partner: Bleuets NB Blueberries
Abstract: Black bulrush (Scirpus atrocinctus) is a common weed in blueberry, often found in wet, low-lying areas. Generally,
growers are using a spot application, either with nicosulfuron/rimsulfuron or glyphosate, to control emerged tussocks. A trial was established
in the spring in a commercial blueberry field near Nixon, New Brunswick to evaluate broadcast herbicide options for black bulrush control.
Bulrush control was significantly higher in an earlier mesotrione application when compared with the late mesotrione treatment. Two mesotrione
applications at the registered rate of 101 g ai/ha had significantly higher control on the August 2009 rating. Nicosulfuron/rimsulfuron, either
alone or in combination with mesotrione, had a high level of bulrush control by the final sprout year rating. Only the two applications of
mesotrione at the registered rate or the nicosulfuron/rimsulfuron followed by mesotrione treatment offered control in the crop year. One
application of mesotrione had limited suppression of hawkweed, although control was highly variable. Two applications at the registered rate
had improved suppression. Nicosulfuron/rimsulfuron suppressed hawkweed.