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Waterhemp resistance to Group 15 herbicides may be more common than expected

A weed science professor at the University of Illinois says the extent of waterhemp resistance to Group 15 residual herbicides is likely more common than previously thought.

Aaron Hager tells Brownfield, “Almost half of these samples that we collected from 84 counties across the state would have been advanced to calculate a resistance ratio.”  He says, “That at least suggests to us that this either resistance or greatly reduced sensitivity is probably more common and widespread.”

He says the use of residual herbicides has become key for farmers, especially soybean growers. 

“Soybean farmers who are thinking and contemplating about doing a layered residual application, and that would be throwing in a residual herbicide with their post herbicide,” he says, “we may simply not get that length of residual that we would normally expect.”

Hager says further research is being conducted to determine the extent of Group 15 resistance in waterhemp.

AUDIO: Aaron Hager – University of Illinois