Weeds are continuing to evolve to become resistant to pesticides commonly used in conventional agriculture. Scientists are searching for ways to control these “superweeds,” which are devastating conventional farms reliant on chemical weed control and invading new habitats. Barnyardgrass is one of the many weeds to recently evolve to a more

Barnyardgrass
Photo Credit: Matt Lavin

invasive, problematic form. Originally growing only on dry land, this weed evolved a tolerance to waterlogged soils, resulting in up to a 10 percent reduction in crop productivity. Herbicides are used to reduce the detrimental effects of barnyard grass, but the development of resistance is rapid, happening within a few years of the introduction of a new chemical. This is just one of over 217 species of weeds that are currently resistant to at least one herbicide, according to the International Survey of Herbicide Resistant Weeds, showing that pesticide use does not solve long-term weed problems.