Seed World

No Evidence to Show Crop-to-Weed Gene Transfer Leads to Resistance

Use of the word “superweed” has snowballed in recent years, along with considerable misinformation that isn’t supported by scientific facts, according to the Weed Science Society of America (WSSA). Most online dictionaries, for example, associate superweeds with herbicide resistance caused by the suspected transfer of resistance genes from crops to weeds. However, there is no scientific evidence that indicates a crop-to-weed gene transfer contributes to the herbicide resistance.
In response, WSSA joins with six sister organizations to recommend a new definition for superweed — a catch-all term used by many to describe weeds that are perceived to be more invasive and to grow more aggressively after developing resistance to herbicides.
“Since superweed is now clearly part of the public vernacular, we decided to offer a definition that more clearly reflects the true source of herbicide resistance,” says Lee Van Wychen, WSSA science policy director.
The science-based definition developed by WSSA focuses on the ability of weeds to develop resistance to virtually any treatment method that is used repeatedly — and exclusively.