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Iowa Soybean Association comments on use of dicamba

Article cover photo
The Iowa Soybean Association is monitoring the dicamba situation in Iowa. (Photo: Joseph Murphy/Iowa Soybean Association)

Editor’s note: The Iowa Soybean Association offers the following comments surrounding the use of reformulated dicamba herbicide and its impact on soybeans and other crops.

Harvest time is here, a reminder that your success as a farmer and ours as an association is rooted in crop performance and productivity. 

One issue the Iowa Soybean Association (ISA) is closely monitoring is the use of reformulated dicamba herbicide and its impact on targeted and off-target soybeans and other crops.

Designed to drift less and be less volatile, the product is for over-the-top use on engineered dicamba-resistant soybeans and a valuable tool for farmers. As you are aware, herbicide-resistant weeds pose a major threat to soybean production and your bottom line. Evasive weeds, especially glyphosate-resistant Palmer Amaranth, water hemp, giant ragweed, marestail and common lambsquarters pose the dual threat of increased production costs and lower yields. Managing them effectively has taken on added importance and urgency.

New formulations of dicamba combined with tolerant soybean varieties were popular tools used by farmers and crop specialists this growing season. The effectiveness of these products lies in dicamba’s ability to mimic natural plant hormones but at high doses, causing abnormal growth and death.

As anticipated, the integration of this product as an on-farm management tool for broad-leaf weed control has not been entirely seamless. Some farmers have heralded the product’s effectiveness while others have identified problems or expressed concerns.

The ISA, Iowa Department of Agriculture and Land Stewardship, seed and tech providers, Iowa State University Extension and Outreach and others have received reports of suspected drift or volatilization/off-target herbicide events related to the use of dicamba. These reports are being investigated. Additional information will be known about the impact of these events as harvest unfolds.

Regardless of the potential problem or its origin, what has received unanimous support from farmers and industry is the importance of having technology that works in the ongoing fight against weeds. To that end, the ISA is:

  • Listening carefully to all reports provided by farmers regarding the use of dicamba and passing that input directly along to the industry.
  • Seeking additional input, especially yield data, from farmers during combine visits and fall/winter grower meetings.
  • Doing everything we can to connect the farmer and technical provider to resolve issues of mutual concern.
  • Routinely communicating the science behind the product, label instructions and farmer and industry feedback using a variety of channels including the Iowa Soybean Review, and numerous social media portals (Facebook and Twitter; our handle is @iowasoybeans).
  • Encouraging science-based and data-driven dialogue. It remains early in the life-cycle of the technology to know the extent of its viability, yield impacts and how it may change 2018 planting decisions.
  • Continuing to emphasize the importance of working together to collect target effectiveness, off-target symptom timing and severity, management and as-applied, climate/weather, topography, lab/chemical, yield, and other relevant If there are problems, we can use data to determine the causes, what the impacts were/weren’t and what we can collectively do to continuously improve the technology and its application.
  • Prompting more effective communication and engagement across and between all parties impacted by this technology including private and public researchers, farmers, viticulturists, gardeners, fruit tree growers, nursery owners and vegetable crop growers.  
  • Engaging in conversations with farmers and industry officials at state and national levels. On the national front, the American Soybean Association is having robust discussions about dicamba with its Research, Precision Ag, & Ag Data as well as the Environment, Conservation and Regulatory Advocacy Teams. These discussions will continue through harvest and winter.
  • Inviting industry representatives to meet directly with farmers to receive input and answer questions about the product and grower experiences this growing season (including a session held earlier this month at a meeting of the ISA board). 

We know that risk accompanies all new technologies. Even with the newly formulated dicamba and dicamba-resistant soybeans system, those risks are real. If not managed carefully, there will be overspray, drift and volatilization issues, losses and lawsuits. None are good for farmers and the soybean industry.

ISA’s mission is to improve the competitiveness of the Iowa and U.S. soybean industries while providing information and expertise to help farmers improve their productivity. We remain focused on this issue, representing the needs of farmers and resolving the concerns of all involved. In the meantime, we welcome your input and ideas on this important matter.

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For media inquiries, please contact Katie Johnson, ISA Public Relations Manager at or Aaron Putze, ISA Communications Director at

For permission to republish articles or to request high-res photos contact Aaron Putze at Iowa Soybean Association | 1255 SW Prairie Trail Pkwy | Ankeny | IA | 50023 | US

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