Micheal D. K. Owen is a professor of agronomy and an extension weed scientist at Iowa State University. He is the co-author of “The Impact of Genetically Engineered Crops on Farm Sustainability in the United States.”
Weeds, like all organisms, respond to selection pressures imposed by the environment. In this case, the primary selective pressure is the repeated use of one specific herbicide: glyphosate.
If farmers adjust their approach to weed control, they’ll be fine.
The solution to the problem for farmers who have yet to cause the evolution of glyphosate-resistant weeds is to adopt a more diverse weed management program that includes tactics other than glyphosate. By altering the selection pressure on the weeds, glyphosate resistance will be slow to evolve.
For those increasing number of farmers who have glyphosate-resistant weeds, the solution is similar but more difficult: adopt alternative tactics that will control those weeds. Of course, often these weeds have also evolved resistance to other herbicides, which, again, is attributed to the historic use of one herbicide as the sole management tactic. In this case, weed control may be more challenging and costly.
Weeds have demonstrated the ability to evolve resistance to herbicides predating the relatively recent adoption of glyphosate-resistant crops. The concern is that crop production systems (corn, soybean, cotton, sugar beets and canola) are now predominantly based on the use of glyphosate. Unless growers use more integrated weed management tactics, the problem of evolved glyphosate-resistance in weeds will likely continue to increase at a growing rate.
While it is unlikely that consumers will experience a direct impact with higher food prices, the farmers will have greater production costs and more difficult management decisions.
As far as what this problem infers about production agriculture is more difficult to assess. However, based on my experience, the risk of herbicide-resistant weeds can be addressed effectively by observing some basic principles of ecology and adjusting management tactics.