University of Tennessee researchers are advising farmers and pesticide applicators to avoid mixing glyphosate with dicamba because of the possibility of volatilization.

Two plant science professors, Tom Mueller and Larry Steckel, applied dicamba and glyphosate mixture to soil in a humidome.

“As expected, more dicamba was detected in the humidome as the temperature increased, with the largest gains coming when temperatures exceeded 85 degrees,” the university said in a news release. “Results also showed that across temperature ranges, the addition of glyphosate to dicamba formulations increased detectable dicamba air concentrations by 3 to 9 times compared to dicamba alone.”

“With increased volatility comes increased potential for off-target movement of the herbicide and injury to non-dicamba-tolerant plants,” the university said.

"Based on this research, we believe glyphosate in the tank mix could be a culprit in why we're seeing some of the drift in fields these past three years," Steckel said.

Since new formulations of dicamba from Monsanto (since bought by Bayer), DuPont and BASF were released in 2017, dicamba drift has resulted in millions of acres in damage to soybeans, trees and ornamentals.

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