AUSTIN, Minn. – The second commercial year of dicamba tolerant soybeans is nearly done. For this upcoming third field year, growers, agronomists and seed companies are reviewing the results. The big question on growers’ minds is what the future of this technology is and how will dicamba applications change.

The first year dicamba tolerant soybeans were commercially available, 2017, was a controversial season. Weed control with dicamba based herbicides was effective and growers were excited to have this tool available. On the other hand, the issues with application caused problems for other growers.

“Many weed control problems that were prevalent pre-dicamba were rectified in 2017. Instead of weed control issues, application concerns and off-site damage were the new concerns regarding dicamba,” said Nick Schiltz, Agricultural Science instructor with Riverland Community College, Austin. “New issues arose that season that have been corrected in some degree in 2018.”

The stringent label restrictions that were put in place at both state and federal levels for dicamba-based herbicides labeled for use on soybeans appear to have been effective.

“Iowa State University Extension reported that offsite movement was lower this year than what it was in 2017,” said Schiltz. “That could be due to more growers are growing dicamba soybeans, more closely following label restrictions, and also better technologies available in the market for growers to use.”

Another contributing factor would be the wet spring and late planting. Dicamba application is restricted to before June 20 in Minnesota. Many growers were not able to meet that application timeframe, so while they had the tolerant varieties in the field, they did not get the herbicide applied. Dicamba restrictions are also set for the first reproductive stage (R1) or beginning flower set in soybeans.

“In terms of yield of the dicamba soybeans, yields have been very nice,” he said. “Amongst all seed companies, dicamba yield results have steadily increased with each successive season. For years, companies stockpiled soybean reserves and invested heavily into research and development into this new mode of action for soybean weed control. With all the generations, better selection and breeding yields better products. The yields are on-par and/or exceeding that of the Roundup Ready soybeans.”

Improved yields and improved application practices are good news for growers looking to take advantage of the technology in 2019.

The seed companies that offer the dicamba tolerant soybeans, Monsanto, Pioneer and Syngenta are looking to expand and push those beans.

“Certainly, there has been a shrinking of non-dicamba soybeans on the market. There has been less and less available. Seed companies understand growers’ concerns for weed control and are pushing new varieties onto the market to use as result,” he said. “This rivals the period of when Roundup Ready was introduced in the late 1990s. With each season, less and less conventional and non-Roundup Ready soybeans were available on a wide scale. In 2018, the same reasons why Roundup was introduced are the reasons Roundup Ready 2 Xtend are being produced. There was acceptance and a big push to release these products for growers to use.”

Not unlike Roundup, growers also seem more inclined to buy dicamba beans as the product as it enters its fourth year in the fields. If anything, planting dicamba tolerant beans is an insurance policy – insurance against potentially difficult weeds and insurance against potential off-target movement.

In the end, it will all come down to costs. Profit margins for growers are getting increasingly tight. For growers getting good yields and weed control without the added trait, the costs may not be justified. Other growers fighting resistant weeds that are taking away yield, they have a real need for this product.

It is still unknown if or how label restrictions may change on the dicamba-based herbicides for 2019 applications.

“Think about how remarkable this science is. 2,4-D was the first major chemical herbicide available in the 1940s. Herbicides were used in ounces instead of in pounds. It was also one of the first non-selective herbicides available to control all broad leaves. With the advances in soybean breeding during the 1980s and 1990s, growers are using a similar herbicide to kill weeds in a broadleaf crop,” said Schiltz. “While it is a wildly scientific feat, there needs to be development and there needs to be refinement on how we utilize this.”