For University of Missouri Extension weed scientist Kevin Bradley, the battle against resistant weeds is one of the key stories from his 16 years with MU Extension.
He says waterhemp has developed resistance to a variety of herbicides, and Bradley and other researchers are working to document all the resistance.
“We’ve been actively screening a lot of waterhemp populations to see what kind of control we’re getting,” he says.
Bradley says weed control needs to involve strategies other than just spraying.
“What’s next, and what we’re looking at with our research, is basically things other than just herbicides,” he says. “I just feel like my whole career has been spent moving from one waterhemp mode of action to the next.”
Bradley says these ongoing research projects range from electrocuting weeds to using cover crops to control weeds. He says herbicides aren’t going to go away, but adding management strategies to herbicide use could be a way to combat ongoing weed resistance.
Adaptation and research are crucial for weed control, Bradley says.
“Nothing ever stays the same,” he says. “The weeds are constantly changing and adapting to what we’re doing.”
Bradley is from Virginia, where he attended Ferrum College before going to Virginia Tech to get his Ph.D. in plant pathology, physiology and weed science. The first thing he noticed when he came to Missouri to start working was how much of an issue waterhemp is. He has jokingly referred to it as Missouri’s “state flower,” and says it has been the top weed threat during his time with MU Extension.
Another pigweed, palmer amaranth, has been a growing issue in fields across Missouri, as it is an aggressive weed that can grow quickly and produce a lot of seeds. These two pigweeds, waterhemp and palmer amaranth, have consistently been the top threats for farmers.
“It’s pretty consistent,” Bradley says. “Palmer amaranth is a growing concern, but it’s still waterhemp number one. I’ve been here for 16 years, and it’s been the top concern for 16 years. The pigweeds rule, and that’s remained the case.”
Of course, a key factor making this year different was the coronavirus pandemic. University schedules and plans were disrupted this spring, and MU continues to work through the coronavirus situation. Bradley says there were some impacts from the virus and adjustments, but for the most part researchers were able to get test plots planted and continue with their research.
“Obviously corona’s affected everybody,” he says. “We were still able to do most of the fieldwork. We’re mostly back to normal now.”
Bradley enjoys the variety of his work, looking for solutions to weed challenges in the state.
“There’s very rarely one day where we’re doing the same thing (as other days),” he says.