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| Department of Agriculture, Aquaculture and Fisheries |
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Abstract: Grass weeds continue to limit blueberry production in New Brunswick. Poverty oatgrass (Danthonia
spicata) can escape typical hexazinone treatment and becomes a harvest issue in the crop year.
Fluazifop–p–butyl is the only registered control option for grass in the crop year. Another potential
product, sethoxydim, has shown good blueberry tolerance in previous trial work and could have a reduced
pre–harvest interval, allowing for applications later in the season. Mesotrione has potential for crop year use and
a tank mix application of both sethoxydim and mesotrione would provide a broad spectrum weed control. A trial was
established near Pennfield, New Brunswick to evaluate sethoxydim, mesotrione and tank mixes for poverty oatgrass
control within a commercial blueberry field entering the cropping phase of production. No crop injury was noted for all
variables measured in this trial, indicating a good blueberry tolerance to crop year applications of mesotrione,
sethoxydim and the tank mixes of these products. A high rate of sethoxydim was needed to suppress poverty oatgrass,
as early suppression from the low sethoxydim rate did not continue in later ratings. Mesotrione alone had no effect on
poverty oatgrass. The addition of mesotrione to sethoxydim did not improve or reduce control of poverty oatgrass, as
all tank mix treatments were not significantly different from the related sethoxydim alone treatment. No difference was
noted between treatments with or without Agral 90 added. Sethoxydim, mesotrione and a tank mix of both products
would be beneficial additions for weed management in the wild blueberry industry.