Market News & Headlines >> Rooting Out "Superweed" Fallacies
Weed scientists are trying to uproot some common misconceptions about herbicide-resistant weeds, often referred to by the catch-all term “superweeds”. The Weed Science Society of America (WSSA) on Wednesday issued a new fact sheet that explores the truth behind two widespread fallacies.
One common fallacy is that “superweeds are a product of rampant gene transfer from genetically modified field crops”. WSSA scientists say genes can be transferred from some crops to certain weed species, but that has not been a factor in the development of herbicide resistance across large areas. The true culprit is overreliance on a single class of herbicides, resulting in selection for weeds that can survive the products in that class.
“Resistance to pesticides is not new or unique to weeds,” says Brad Hanson, Ph.D., a member of WSSA and Cooperative Extension weed specialist at the University of California at Davis. “Overuse of any compound class, whether antibiotic, antimicrobial, insecticide, fungicide or herbicide, has the potential to lead to reduced effectiveness."
Herbicide-resistance weeds were first reported more than a half century ago, but integrated weed management strategies that included increased tillage, more hand weeding and use of multiple herbicides kept them largely in check. However, it has now become common in some cropping systems for farmers to continually use a single class of herbicides to the exclusion of other weed control methods, and this has led to the growing problem with herbicide-resistant weeds.”
Another common fallacy is that “superweeds” possess "supercharged abilities to muscle out competing plants in new and more aggressive ways”. Many believe today’s herbicide-resistant superweeds exhibit properties unlike anything ever seen before.
But WSSA scientists say bully-like weed behavior isn’t new. In the absence of herbicides, resistant weeds are no more competitive or ecologically damaging than their non-resistant relatives, they say. All weeds – herbicide resistant or not – can outcompete other more desirable plants for water, nutrients, sunlight and space.