In the latest development in the dicamba saga, EPA approved over-the-top application for years to come of three dicamba herbicides.

As DTN reports, Bayer’s Xtendimax, BNSFs Engenia, and Syngenta’s Tavium dicamba-based herbicides were each granted five-year registrations with a new restrictions, including a cutoff date of June 30 for soybeans and July 30 for cotton, after which dicamba cannot legally be used for over-the-top application.

There are several other new restrictions EPA placed on dicamba use in response to extensive damage to neighboring crops, gardens, and native vegetation from the highly volatile herbicide drifting across the landscape. See the full ruling docket here, but the big changes include an increase in the downwind buffer from 110 feet to up to 310 feet, and a requirement that applicators use pH buffering agencies to lower volatility. Existing requirements related to wind conditions, sprayer speed, and time of day remain in place from previous labeling.

In another important change, EPA specified that states “will no longer be permitted to use Section 24(c) of the Federal Insecticide, Fungicide and Rodenticide Act to further restrict the federal label.”  States who want to enact stricter rules will have to do it via the more onerous Section 24(a) instead, “which requires individual state regulatory or lawmaking processes” (Unglesbee, 2020).

Meanwhile, we are getting a fuller picture of the cost of dicamba drift damage. In recent reporting, Investigate Midwest reports that the EPA’s “own data shows that the damage from the weed killer was worse than previously known. The pesticide harmed tens of thousands of farmers, overwhelmed state agriculture departments and damaged research plots across the United States, according to documents the federal agency released” (Hettinger, 2020).

Investigate Midwest dug through the documents released by EPA as part of the new dicamba decision, and put together some new metrics on the extent of dicamba damage:

• 5,600 farmers have reported drift damage to manufactures Bayer and BASF
• EPA’s own estimates predict up to a 25-fold underreporting rate
• 4 percent of all soybeans, or 65,000 fields, were damaged in 2018 – 4.1 million acres in all, the highest annual total yet reported
• “Dicamba fatigue” is hitting state ag departments hard, including in the pocketbook where millions are being spent to investigate complaints, while other priorities fall to the wayside
• Research plots at the Weed Science Society of America’s research stations reported 30% losses in 2019
• Drift damage was reported in dozens of natural areas in affected sates, including 86 in Arkansas

Investigate Midwest analyzed the potential impact of the EPA’s ruling and found that there is still a lot of room for error. “About 60% of damage incidents have been reported after June 30, the new cut-off date.” And that 240-310 foot buffer? Some damage reported has been more than a mile and a half from the source (Hettinger, 2020).

They also uncovered some interesting data that seems to support the theory that many farmers are planting dicamba-tolerant crops as defense again the volatile herbicide. EPA records show that in 2018, “only 51% percent of farmers sprayed dicamba on dicamba-tolerant crops,” compared to a 90% spray rate on glyphosate and glufosinate-resistant crops (Hettinger, 2020).

With the EPA’s latest registration decision, dicamba drift will continue to make news, and we will continue to follow and report back highlights like these.

Sources:

Johnathan Hettinger, “EPA documents show dicamba damage worse than previously thought,” Midwest Center for Investigative Reporting, Date Published: October 29, 2020, Date Accessed: November 2, 2020.

Emily Unglesbee, “EPA Registers Dicamba Again,” DTN Progressive Farmer, Date Published: October 27, 2020, Date Accessed: November 2, 2020.