Guide on newly approved herbicides available from Office of Indiana State Chemist

WEST LAFAYETTE, Ind. - The Office of Indiana State Chemist (OISC) has published a set of guidelines for soybean farmers who are considering the use of newly approved dicamba-based herbicide products.

Last year, the U.S. Environmental Protection Agency registered Monsanto’s XtendiMax and BASF’s Engenia herbicides for pre-emergence and post-emergence use on dicamba-tolerant (DT) soybeans.

The dicamba outreach publication was developed by pesticide program administrator Dave Scott of OISC and Purdue Extension weed specialist Bill Johnson to explain how to legally and effectively use dicamba-based herbicides on DT crops.

Dicamba-based herbicides are best used to treat giant ragweed, marestail, waterhemp, Palmer amaranth, lambsquarters and morning glories.

“This product is a sorely needed tool in controlling glyphosate, ALS, and PPO resistant broadleaf weeds in soybeans,” Johnson said. “It’s very effective if used correctly.”

Using dicamba-based herbicides requires more caution than other more commonly used herbicides, Johnson said.

“This is a new tool for controlling weeds in soybeans, but it has more restrictions than any other herbicide I have encountered in my life,” he said.

Scott expects the labels and legal prohibitions on dicamba-based herbicides to be in development for some time, which is why the publication was created.

Dicamba is a highly active herbicide at very low levels, meaning it can damage many desirable crop and landscape plants at very low doses if it moves off the intended area.

“Because this tool will be widely used and misused, and the fact it can injure non-target vegetation at such low doses, the potential for lawsuits and cancellation of registration is also very high,” Johnson said.

“Past experience with dicamba herbicide use has demonstrated that potential damage to non-target crops and vegetation is considerable and must be avoided if these products and herbicide-resistant technology is to survive,” Scott added.

The publication is available online at https://www.oisc.purdue.edu/pesticide/pdf/dicamba_outreach_011117.pdf.

Questions should be directed to Scott at scottde@purdue.edu or Johnson at wgj@purdue.edu. 

Writer: Mikaela Wieland, mwieland@purdue.edu 

Sources: Dave Scott, 765-494-1593, scottde@purdue.edu

Bill Johnson, 765-494-4656, wgj@purdue.edu

Agricultural Communications: (765) 494-8415;
Darrin Pack, dpack@purdue.edu 
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