It’s been discovered that Monsanto’s Roundup herbicide encourages the growth of toxic fungus in wheat. Genetically-modified wheat, also produced by Monsanto, has been especially engineered to be immune to Roundup, so that an entire field can be sprayed and only the weeds will be affected.
Andy Coghlan writes in New Scientist this fungus already destroys one-fifth of the wheat in Europe, and produces toxins that can kill both humans and animals. Since the GM wheat isn’t killed by the herbicide, farmers are likely to spray more often, producing even more toxic fungi. Switching to other herbicides isn’t the answer, since Roundup is one of the least harmful, because it quickly breaks down in the soil.