Production Blog

Keep an Eye on Your Dicamba Rules

Keep an eye open for state regulations that may exceed federal label regulations if you plan to use dicamba herbicides this season. (DTN photo by Pamela Smith)

DECATUR, Ill. (DTN) -- Reporting on the ongoing saga of whether Arkansas farmers get to use dicamba herbicides this season has become nearly a full-time job.

As DTN reported Thursday, a handful of farmers in that state temporarily skirted the ban through legal action. The majority of those applicator have now lost access again in the appeals process.

See that report here:…

Now, the Missouri Department of Agriculture has extended the cutoff date for southeast Missouri counties to June 10 through a 24c Special Local Needs label for Engenia, FeXapan and XtendiMax.

The original cutoff date was set for June 1, 2018, in Dunklin, Pemiscot, New Madrid, Stoddard, Scott, Mississippi, Butler, Ripley, Bollinger and Cape Girardeau counties. The cutoff date for all other Missouri counties is still July 15, 2018. After the cutoff dates, no applications (burndown, preplant, preemergence and postemergence) may be made.

In a news release, Missouri Director of Agriculture Chris Chinn attributed the move to delayed planting conditions. "We have been diligently monitoring weather to determine what, if any, adjustments need to be made to the cutoff dates, as we have said we would from the beginning," said Chinn. "Because of the wet, cold spring, planting has been delayed. This extension will give farmers extra days to use these products prior to the cutoff date." Find that announcement here:…


The thing to remember is that while the U.S. Environmental Protection Agency (EPA) gave spray applicators some detailed labeled requirements to follow for the three dicamba herbicides approved to use in the Xtend soybean and cotton crop system, some states can and have added their own stipulations.

In Minnesota, for example, applicators have both a cutoff date of June 20 and a cutoff temperature. In that state, applicators are not to apply if the air temperature of the field at the time of application is over 85 degrees Fahrenheit or if the National Weather Service's forecast high temperature for the nearest available location for the day exceeds 85 degrees. Find those details here:….

Research has shown that dicamba volatilization and the potential for injury associated with that movement increases with temperature. Label guidelines and restrictions are meant to reduce physical movement of spray particles during application, but volatility is not prevented by federal label language.

This week DTN launched a series called Dicamba Details. That series covers the main reasons EPA used for tightening the labels for the 2018 season: physical drift, tank contamination, misuse, temperature inversions and volatility. That series of stories will stretch into next week.

Between the lines of these articles is a plea for good judgment. Opening the calendar up for more spraying doesn't necessarily mean the thermometer got the memo.

And as Illinois Fertilizer and Chemical Association President Jean Payne has noted over and over: "Dicamba is not a rescue treatment. If you view it as such, your weed-management system has already failed."

All of this becomes even more critical as the planting season stretches out and the spray window becomes condensed.

At the risk of preaching, we will say it again: If you aren't willing to use the products correctly and wisely, don't use them at all.

The future use of dicamba, and many other crop-management tools, may depend on it.

Dicamba Details articles to date can be viewed at:

Decision Time for Dicamba:…

Let's Get Physical: How Does Particle Drift Happen?:…

Clean Up Your Act:…

Pamela Smith can be reached at

Follower her on Twitter @PamSmithDTN



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