2019 Dicamba Usage Update

As we wait for spring planting to begin, it’s a good time to review South Dakota’s dicamba guidelines, which have been updated for 2019.

Tom Gere, agricultural services assistant division director at the South Dakota Department of Agriculture, shares the biggest change.

“For 2019, June 30 is the last day that dicamba products can be applied in South Dakota. The 24(C) is a special, local label,” he says. “It reads that you can apply the product 45 days after planting, up until R1 or June 30, whichever comes first.”

“June 30 is the cutoff date because a significant number of our complaints about dicamba drift or volatility during the last two years have occurred after July 1.”

When dicamba drifts, it can damage crops that are not dicamba-tolerant, and in some cases, gardens. “We’ve seen everything from very little damage to potential crop loss or loss of one’s garden,” Gere explains.

The Label Is the Law

“The label’s the law. Anyone who is going to be applying dicamba needs to be certified, and they also need to take the annual dicamba training.”

Gere says dicamba is “touchy.” It can only be tank-mixed with certain products. “There’s just a whole list of certain things applicators have to remember when they’re applying dicamba.”

Wearing proper protection equipment (PPE) is also required.

Weed Control for the Long Haul

Farmers are increasingly using dicamba on tough-to-control weeds that are resistant to glyphosate. According to Gere, the biggest problems in South Dakota are kochia and pigweed species like waterhemp.

“There are a lot of weeds out there that are currently resistant to glyphosate,” Gere says. “Dicamba has a different chemistry or different mode of action that’ll go after these tough-to-control weeds differently.”

One of the reasons it’s critical to use weed control products according to the label is that regulations are designed partly to prevent the development of herbicide-resistant weeds.

“There’s already some documented resistance in regards to dicamba,” Gere says. “That’s why it’s important to follow the label and use different modes of action out there on your corn and soybean fields to prevent resistant biotypes.”
“Dead weeds don’t produce seeds. They’re less likely to reproduce and be tolerant to different chemistries,” he says. “I definitely recommend putting down a pre-emerge out there on your acres and then coming back with a post-emerge product that works differently. The earlier you get out there, the better off you are, and I know with the way the spring’s panning out might be a little bit tougher this year.”

For more information on dicamba, visit the South Dakota Department of Agriculture’s ag services site at https://sdda.sd.gov/ag-services/ or call 605-773-4432.