“Farmers need to be aware of how much marestail is in their fields,” says Travis Legleiter, weed science program specialist, Purdue University. “This spring we might have more marestail or marestail further advanced in its growth stage.”
Use burndown to gain early season control of the weed, but be mindful of best management practices. Use an effective herbicide in a mix that targets multiple sites of action. Legleiter advises avoiding 2,4-D and glyphosate for burndown. Marestail is easiest to kill between 2" and 4" tall.
Make sure your herbicide is not in one of the five groups marestail is resistant to: PSI electron diverter (22), EPSP synthase inhibitor (9, glyphosate), ALS inhibitors (2), Photosystem II inhibitors (5) and PSII inhibitors (7).
Marestail does not recover well from deep tillage, and it suffers when the crop reaches canopy. Continue to scout after tillage and herbicide application to determine weed kill and if you have resistance issues.