Working Group Begins with September 25, 2019 Meeting

Oct. 14, 2019
North Central IPM Center computer

Working Group on Dicamba, 2,4-D Drift to Focus on Specialty Crop Drift and Recommended Reporting Techniques

Dicamba and 2,4-D drift has gained national attention in the past few years. Following a meeting last winter with North Central IPM weed scientists, it was named an emergency issue and a new working group was created by researchers at Purdue and Ohio State. 

As part of this initiative, weed specialists who work with both agronomic and specialty crops met online in September, along with representatives from North Central IPM and the USDA. From this gathering, organizers identified educational efforts that could help address this issue across the region. 

The group decided to work on the following initiatives in the coming months. 

  • A detailed educational guide to help farmers recognize and understand their options when tit comes to reporting drift damage. 
  • An anonymous survey to measure how prevalent drift is among horticultural crops. 

Meeting attendees noted that dicamba and 2,4-D drift complaints reported to state regulatory agencies were down in some states but did not feel this should necessarily be interpreted as fewer drift incidents happening. Indeed, many of the specialists said the decrease in official complaints does not match what field agronomists and crop specialists are reporting. Regulatory agencies in many states have been overwhelmed with requests and therefore slow to respond. Even when responses come, there is little chance of farmers being compensated for lost and damaged crops since sources of drift are difficult to track and even harder to prove. 

The group agreed that specialty crop growers and homeowners may also be less informed than agronomic crop growers about how to recognize and report drift. Specialty crop producers also have their business interests to consider. In the case of slight damage, reporting drift may prevent their crop from being sold since there are currently no tolerances for dicamba residues. Thus, for growers of produce, tobacco, and organic crops, reporting drift may bring huge economic risk with little chance for benefit. 

In summary, we don’t really know how wide-spread drift may or may not be in horticultural and other specialty crops. 

The group also advocated for more research on specialty crop tolerance levels, the fate of these herbicide residues in plant tissue and soils over time, and on factors that influence low concentration volatilization. Some related work is ongoing but is funded by herbicide companies and registrants.

Possible regulatory measures were also discussed such as temperature restrictions and establishing Inadvertent Residue Limits for dicamba and 2,4-D. Research on horticultural products may advance the case for regulatory action and future action should be discussed after the survey results come in. The survey may also be used to more widely distribute the educational materials created, and to learn about other needs this group has related to drift. 

For more information, contact Douglas Doohan or William Johnson at