EPA herbicide restrictions aim to protect snake species in Minnesota counties where it doesn't live

This article has been corrected to say that a reference to a list of endangered species in Minnesota also included threatened species and species of note.

WASHINGTON — When the EPA announced new restrictions on a herbicide in Minnesota in order to help protect an endangered species, it did not identify the species it is trying to protect.

It turns out, according to snake experts, it may be trying to protect a snake that has not lived in the state for at least 50 years.

The herbicide affected is Enlist Duo for use on Enlist soybeans.

The restrictions apply to six Minnesota counties: Clay, Marshall, Polk, Redwood, Renville, and Stearns. Polk County is the top soybean producing county in the state.

But the species? Similar EPA restrictions were put in place to help protect a burrowing beetle in Nebraska and South Dakota. A plant would be a good bet. The list of endangered, threatened plant species of concern in Minnesota is far longer than that of mammals, birds and fish combined. Or perhaps it could be a pollinator.

But in an email response to Agweek, the Environmental Protection Agency identified the species as a snake — the eastern massasauga rattlesnake.

According to the Minnesota Department of Natural Resources, the eastern massasauga is one of only two venomous snakes in the state, the timber rattlesnake being the other. "Both are found only in the southeastern counties and are rarely encountered," the DNR's web page on snakes says.

But none of the counties where the restrictions apply are in southeast Minnesota.

For the eastern massasauga, "there is no evidence of established breeding populations on the Minnesota side of the Mississippi River," the DNR says.

It can be found on the Wisconsin side of the river, and is native to several other states to the east and south of Minnesota.

Jeffrey Leclere with the Minnesota Herpetological Society said the massasauga "has never been documented in those counties," and he said they don't have the habitat the species would need.

The six somewhat scattered counties "are not even close to an area that used to have massagaugas."

The DNR website says, "Its occurrence in Minnesota is based on a few reliable sightings in the southeast part of the state, and one specimen whose collection location is questionable."

In an email, the DNR said that in 2016, the U.S. Fish and Wildlife Service listed the species as federally threatened. In its assessment, that agency considered the species extirpated from Minnesota, in other words, locally extinct, given that there have been no verified records from within the state in the past 50 years.

But the EPA says it relies on information from the U.S. Fish and Wildlife Service and the National Marine Fisheries Service.

"Based upon the current species distribution information from FWS that was used to evaluate the Enlist products, the Eastern Massasauga is distributed across 87 counties in Minnesota. EPA does not track additional species or habitat information collected at a state or local level by other organizations," the EPA said in an email to Agweek.

EPA also said Minnesota was the only state where the eastern massasauga was found "on field," but was found off field in 10 other states, so there were no additional Enlist restrictions in those states.

The U.S. Fish and Wildlife Service could not be reached for comment but a search of its website includes a 2021 article that says the snake is most common in Ontario, Canada, and in Michigan — not Minnesota.

The Fish and Wildlife Service interactive map for the snake's range does not include Minnesota.

David Kee of Minnesota Soybean Research and Promotion Council didn't know what species the EPA was trying to protect when he spoke with Agweek. But he was curious about the geography of restrictions.

Polk County is a large county in northwest Minnesota and Marshall borders it to the north. Those two counties almost completely surround Pennington and Red Lake counties, where there are no restrictions.

"Kinda makes you scratch your knot a little bit," Kee said.

Kee's guess was that the species must exist the west end of Polk and Marshall counties, but EPA chose to apply restrictions to the whole county.

EPA said it can refine restrictions to sub-county levels such as townships or a watershed district, "However, in this case, EPA and Corteva (Corteva Agriscience, the company behind Enlist soybeans and herbicide) decided to keep the labels simple, clear, and complete to avoid confusion and complexity with the registration and interpretation."

While EPA said the snake could be found in all 87 counties, the six counties that were chosen for restrictions had the greatest risk for exposure to Enlist Duo.

Kee said soybean growers in Minnesota are lucky compared to some other areas where both Enlist 1 and Enlist Duo herbicides have been restricted.

Kee said growers can add glyphosate to Enlist 1 to create the same effect as Enlist Duo but need to be very careful about following the proper steps for tank mixing and be aware that tank mixing can cause problems with clogging up sprayer tips.

Kee said as more herbicide labels using glyphosate, which is the primary ingredient in Roundup herbicide, come up for EPA review, there may be more restrictions coming.

"As the other labels are up for review, we may see more restrictions," Kee said.

Kee said Corteva is working with growers who may have already purchased a chemical they can no longer use.

"They are in the process of making the farmer whole," Kee said.

Matthew Krueger, a grower in the East Grand Forks area of Polk County, said with Enlist 1, with 2, 4-D as the active ingredient, still available, it should not be a significant setback for growers.

Kee said herbicide dealers will play a key role in helping growers in the counties with the new restrictions. EPA referred growers to county Extension agents for advice.

Kee said any missteps by farmers could results in "poor efficacy or outright fines."