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Take Control of Dicamba

Darrin Holder, Agronomy Manager, WinField United 4/24/2020


This illustration shows 15 GPA through a TTI11004 nozzle at 40 psi in a crosswind application. Spray on the left contains dicamba, Class Act Ridion, glyphosate and Drift Reduction Adjuvant. Spray on the right has dicamba, Class Act Ridion, glyphosate, OnTarget, and InterLock. Notice the droplet uniformity gained with the addition of the InterLock.
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It’s May, and that means it’s time to use all our resources to help control hard-to-kill weeds in soybeans and cotton. First and foremost, a weed that never emerges will never be a post control problem. Therefore, regardless of what trait platform you have planted on your farm, the use of burndown and pre-plant residuals are a must to take pressure off post-herbicide programs on tough weeds.

To help with problem weeds, many folks have adopted dicamba into their system over the past few years, and it is no exception to any other herbicide. We have to get the adjuvants right, and any tank mix it is in, to make it be the best it can be. The industry has learned quite a bit about managing this new post-applied molecule and WinField United has continued to test application methods and products for it specifically. New research from WinField United has reinforced and broadened findings from earlier this year regarding the control of fine particle drift.

What we found

First, WinField United researchers recently discovered that even if a drift reduction adjuvant (DRA) is included in the spray tank, flexible membranes called “bags” are created (think of a bubble). Once these bags leave the spray nozzle and hit a crosswind in the field, they break, creating many fine droplets that can easily drift where they shouldn’t. We call this phenomenon “bag breakup.”

After identifying this occurrence, we found that InterLock® adjuvant disrupts the formation of these flexible bags so that the phenomenon is less likely to occur.

Earlier this year, we reported on research conducted at the WinField United Innovation Center that showed including InterLock adjuvant in the spray tank helps control fine-particle drift that DRAs alone cannot. We discovered that including both InterLock adjuvant and a DRA in the tank, along with a water conditioner, reduced driftable fines by 60 percent.

The bottom line is this: farmers should still include a DRA in their spray tanks, which improves spray quality and meets label requirements for many tank mixtures. And even with a DRA, there are always going to be fine droplets with spray applications. However, adding InterLock to the tank further optimizes that spray application by reducing the potential for drift. Farmers can apply a low-use rate — just two ounces of InterLock adjuvant — per acre for that extra reassurance.

Tank mix partners

For dicamba herbicide applications, WinField United recommends using InterLock adjuvant technology along with OnTarget® adjuvant, which is a DRA. Additionally, adding a water conditioner to the tank when glyphosate is used is strongly recommended, since water used for spray applications often contains cations that can limit glyphosate effectiveness. Designed specifically for dicamba technologies, Class Act® Ridion® by WinField United is a non-AMS water conditioner that helps neutralize these cations. Class Act Ridion also contains a surfactant and CornSorb® additive for increased herbicide efficacy.

Now is a great time to talk with your local Co-op agronomy specialist about how these findings can help you optimize your herbicide applications in 2020. This can save you respray costs and help ensure your crops are getting the protection you’re paying for. Your Co-op agronomy specialist can also advise you on disrupting bag breakup and reducing driftable fines in their fields during the 2020 growing season and beyond.

For farmers and applicators who wish to stay up to date on the latest adjuvant research from WinField United, visit

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