Q: Is early weed control always a solid tactic?
A. It’s been well established that competition from early-emerging weeds is most detrimental to crop development. Weeds emerging along with the crop compete for moisture, fertility and light before the crop has a chance to get the upper hand by developing its root system and getting above any later-emerging weeds. But how early is too early for weed control? Weeds are emerging from various depths and germinating at varying times, making the spray timing decision difficult.
Do I spray now or wait? Planning ahead can help you decide. Too often we focus on controlling what we can see, forgetting the value of soil-applied pre-emergent products. There are now more options available to growers for both broadleaf and grassy weed control in front of more crops. Many of these products can be considered a great setup to a complete weed control program, and often have the added benefit of using alternative herbicide modes of action such as Group 3, 8, 13, 14 or 15.
Adding these herbicide groups can decrease early weed pressure on a crop while also providing an opportunity to use an alternate herbicide group to control weeds in crop for effective herbicide-resistance management. While pre-emergent products often require a followup in-crop application of herbicide, they are part of a complete weed management program that can help a crop achieve its full yield potential.
Scott Anderson, P. Ag, CCA, is a manager of agronomic services for Nutrien Ag Solutions in northwest Saskatchewan