ST. PAUL, Minn. – As soybean growers shift their focus towards planning for the 2020 growing season, two questions remain: Can dicamba-based herbicides be used, and when can they be applied to soybeans?
In addition to the federally mandated regulations, the Minnesota Department of Agriculture (MDA) recently released the state’s rules for dicamba applications on soybeans.
“We are not making any changes and we’re, again, instituting the June 20 cutoff for the 2020 growing season,” said Thom Petersen, Minnesota Commissioner of Agriculture. “We decided to announce it a couple of weeks earlier this year because we wanted farmers to have plenty of time to make decisions.”
Dicamba has had a contentious beginning since tolerant soybeans hit the market three years ago. The first applications on beans were made during the 2017 growing season.
The product is volatile and has a tendency to lift off the plants and drift if applied during the wrong weather conditions. It then settles back down out of the air, often times on crops and plants that are not tolerant to the herbicide, causing damage.
In 2017, the MDA investigated 253 instances of off-target movement of the herbicide, impacting 250,000 acres.
“Our decision came down to the investigations that we had from farmers in Minnesota,” Petersen said. “We've been able to cut it down from 253 in 2017 to less than 20 investigations in 2019. We've been able to go from a quarter of a million acres down to less than a thousand acres impacted by keeping that June 20 date.”
When Minnesota set the June 20 cutoff date for the 2018 and 2019 growing seasons, it was the earliest cutoff date among the Midwest states. However, in 2020, other states will be joining Minnesota with the early cutoff.
“We see other states adopting the earlier date that Minnesota has. Both Illinois and Indiana are moving towards that date after having a later date this year and then having problems,” he said.
Illinois has significantly more reports of off-target dicamba movement than Minnesota. As of Aug. 23, there were 590 dicamba related complaints.
Other states in the region, South Dakota and North Dakota, have a June 30 cutoff date. Wisconsin and Iowa have not yet released their dates, but will likely continue with June 30 as the final application date.
For the last two growing seasons, it has been a challenge to meet the cutoff date. Both years were unseasonably wet and cold in the spring, delaying planting, as well as post-emerge herbicide applications.
“We know, for some farmers, June 20 was a really long day this year and they worked hard to get that in, but there are other products that they can use after June 20,” Petersen said. “In a normal growing season, even a halfway normal growing season, June 20 would be just fine.”
Dicamba remains an important weed control tool for farmers, particularly for those dealing with glyphosate and other herbicide-resistant weeds in their fields.
The goal of the MDA is not to make the use of dicamba so difficult that farmers can’t use it, but to ensure it is used in a manner that protects other growers, allowing the product to remain on the market and be used as an effective weed control tool for years to come.
“In Minnesota, it's been tough the last couple of years, so we're hopeful that all the way around, planting through harvest, that we just have a much better year next year,” he said. “We're keeping the same time that we had, and we are getting the message out there earlier so farmers have time to make those planting decisions now.”