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It is not too early to think about how you are going to control weeds in 2016. Many of you will remember how ineffective early weed control was last spring due to all the rain that either prevented spraying or diluted the impact of residual herbicides.

We all know that you can no longer rely on glyphosate to control all weeds and that programs today need either a burndown, a residual or another post as a tank mix with glyphosate. In addition, fall control of winter annuals such as marestail is becoming an increasingly important option.

Marestail, a very common winter annual in Illinois, is often glyphosate-resistant and is tough to control once it bolts in fields in the spring. Marestail control in next year’s soybean fields should begin with fall or spring applications of dicamba, 2,4-D, Canopy® EX or Autumn™ Super. However if you have ALS-resistant marestail make sure you have 2,4-D or dicamba in the tank mix. Fall treatments should be delayed until November after the fall-germinating marestail has emerged and is in the small rosette stage.

If spraying in the spring, be aware of the intervals required between application of these herbicides and planting soybeans, particularly with 2,4-D.

BASF’s Kixor®-containing Sharpen®, OpTill® or Verdict® can be applied as a burndown to control marestail before soybean emergence. As with any post application, spray when the marestail is under 4 inches in height and use an adequate volume of water (15 gallons per acre or more) to get good coverage, but don’t expect much residual control.

Other residual preplant herbicides that help with burndown and residual control of marestail include Valor® and FirstRate® herbicides including Valor XLT, Fierce®, Fierce XLT, Envive®, Trivence®, Enlite®, Authority® First, Sonic®, Gangster®, or Surveil®.

Marestail is best controlled in the fall or in the spring before it begins to bolt. FirstRate or Synchrony can be tank mixed with glyphosate as a post application. You can also apply Liberty® as a burndown before planting or as a post on Liberty Link® soybeans.

Agronomist Dr. Daniel Davidson posts blogs on agronomy-related topics. Feel free to contact him at djdavidson@agwrite.com or leave a comment below.