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Saskatchewan's Ministry of Agriculture is letting producers know a recent result of a study that could change how producers use herbicides on shrubs.
In 2019, the government looked to demonstrate and compare two chemical control options in southwest Saskatchewan to control the encroachment of a pair of woody species on rangeland: Western snowberry (Buck brush) and Wolf Willow.
To do that, they applied 2 herbicides on July 11, 2019:
- Reclaim II ‘A’ at 81 g per acre, plus Reclaim II ‘B’ at 0.69 L per acre,
- 2,4-D Ester at 852 g per acre, plus Dicamba (Oracle) at 710 g per acre,
The plots were monitored for three consecutive years (2019-2021) for the results from the initial herbicide treatments that occurred in 2019.
At the end of the 3rd year, the following results were found, with Range Management Extensions Specialist Trevor Lennox detailing the findings.
"For the initial year of application, we applied in July for both treatments, the 2,4-D dicamba as well as the Reclaim II, gave equal control the first year. But going the second and third years after, the 2,4D dicamba gave no residual control in the second and third year, so we did see those shrubs coming back. That was the western snowberry, whereas the reclaim gave very good control of second year, but by the end of the third year we're starting to see a few shoots coming again. So we knew that residual activity of that chemical was wearing off."
"The wolf willow on the other hand, we found a lot easier to kill in our projects. We found that both products worked equally and gave good control over the term of the project. So the 2,4D dicamba treatment was equal to the Reclaim 2 treatment for wolf willow."
Lennox says those findings are being shared to help producers decide what's best for their fields.
"We're sharing information out to producers to help them understand that there are some herbicide options to help reduce the continued expansion of brush on their range land. Obviously, the herbicides definitely come with the cost, we were looking in the low to mid $50s in terms of per acre for the herbicide rates for the cost, but strategically it can definitely be one way of slowing down the continued expansion of brush across pastures and rangelands."
Lennox says that mixing that method with mowing is another possible way to extend a herbicide's control.