You may be eyeing the new dicamba-based postemergence herbicides — BASF’s Engenia, DuPont’s recently approved Fexapan and Monsanto’s XtendiMax — for controlling increasingly resistant broadleaf weeds in dicamba-tolerant soybeans and cotton. But long before you tank-up with either product, be sure you know their label regulations and rules.

Now, you can take a quick online quiz to be certain you don’t mess up. More on that shortly.

Fexapan and XtendiMax use “VaporGrip” technology to reduce volatility, according to Bill Curran and Dwight Lingenfelter, Penn State Extension weed control specialists. DuPont’s Fexapan is identical to XtendiMax. Engenia uses a new dicamba salt to reduce volatility by 70%.

Applied correctly, all three are part of the Roundup Ready 2 Xtend program and can control glyphosate-resistant species of Palmer amaranth, waterhemp, marestail and giant ragweed, plus other broadleaves. They aren’t meant to be “rescue products,” stresses Chad Asmus, BASF technical marketing manager. “You’ll still have to use a good residual herbicide so you don’t miss late-emerging weeds.” Engenia, for instance, can’t be applied later than R1 soybean (bloom) stage.

EPA restrictions
Restrictive labels prohibit application if wind is blowing off-target toward specific crops such as tomatoes, vine crops, grapes and others. It doesn’t take much breeze or product to cause drift damage, warn Curran and Lingenfelter.

That’s why only specific nozzles outputting extra-coarse to ultra-coarse droplets can be used. That includes TTI11004 and 11005 nozzles and comparable nozzles of other brands.

The labels also specify maximum ground speeds (no more than 15 mph), boom height (no more than 24 inches above target), spray volume (no less than 10 gallon per acre), wind speed limits, what you can tank-mix, and where you must leave 110-foot downwind buffers for sensitive crops.

As of March 1, EPA prohibited tank-mixing glyphosate with these products. But a number of other residual herbicides can be tank-mixed with them. Asmus is hopeful the glyphosate tankmix restriction will be lifted by this season.

Ace the Smart University quiz
BASF has expanded its On Target Application Academy stewardship program with an online Grow Smart University training module to provide up-to-date information plus easy-to-access best practices for proper application. It poses 10 multiple-choice questions, then gives you the correct answers, plus links to more details.

It’s an easy, unintimidating way to refresh your know-how on using these products. “Our goal is to keep Engenia on target,” affirms Asmus.

Access the module by visiting growsmartuniversity.com. Register, then click on the herbicides tab.

This writer took the quiz and got seven of the 10 questions correct the first time through. After a quick review, he “aced” the test.