It’s mid-April and the weeds are growing in eastern Canada.
Overall, good weather has many fields one month ahead of schedule, and in some cases, two months ahead of backward 2019 spring conditions, notes BASF agronomist Rob Miller. That means it’s time for growers to tackle perennial weeds and winter annuals like Canada fleabane before planting, he says.
On this episode of RealAgriculture’s Corn School, Miller also discusses the need for residue management this spring. With the delayed 2019 corn harvest, growers had little time to squeeze in fall tillage and many fields have accumulated high levels of crop residue that will promote weed pressure and could also be problematic for planters.
Herbicide carryover is another issue growers should have on their radar. With delayed planting in 2019, many growers applied residual herbicides later than normal. Much of the crop was planted in June and may have been sprayed in early July. This spring, if things go well, herbicides will go down early. If crops are also planted early, it will shorten the interval between microbial activity and there may be some evidence of herbicide carryover damage.
Miller notes, however, that herbicides are tested for safety at twice the recommended rate to ensure there is no overlap from one season to the next. He’s confident that any herbicide carryover will not result in yield loss. (Story continues after the video.)
As spring continues, Miller believes growers will also see a different story unfold for pre-emergent herbicides. If the weather continues to co-operate pre-emerge products will be able to keep weeds at bay until the crop is able to close canopy and starve late-emerging weeds of the sunlight they require to grow and impact yield.
But if spring weather turns cool and the crop is slow to emerge and growth is delayed, growers may have to turn to two-pass weed control. If that is the case, Miller says growers should be confident they can get the job done. He notes that two-pass weed control systems are typically the most efficient and help growers maintain yield potential throughout the season. They are also highly effective in reducing the weed seed bank and setting a field up for future weed control success.
In the video, Miller also notes key best management practices for weed control success including employing multiple effective modes of action and ensuring adequate water values.
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