News

Tracking herbicide-resistant weeds

A weed scientist says researchers are gaining ground in tracking the spread of herbicide-resistant weeds.

Dawn Refsell with crop protection firm Valent USA helps growers manage the two most common resistant-weed species: palmer amaranth and water hemp.

“You want to follow river tributaries in reverse back up from the Mississippi, that’s a good way to follow resistance.”

She says weed seeds are also being introduced through contaminated sources.

“Cotton seed for example, and now we’re also seeing CRP or any of your cover crop seed might have some of the palmer or water hemp seed in it.  So it’s spreading seed that way.”

She echoes what others in the industry are recommending in the fight against resistant weeds: a management program that includes multiple modes of action with pre and post applications.

Brownfield spoke to Refsell during the Farm Progress Show in central Iowa earlier this month.