The use of the harsh, best-selling chemical pesticide, glyphosate—sold as Monsanto’s Roundup—is causing the widespread growth of resistant ‘superweeds.’ Used on genetically modified crops including Monsanto’s canola, cotton, corn and soy, which dominate much of the nation’s farmland, glyphosate resistant superweeds were first noticed in 2010, spreading out across farms, damaging crops, farm equipment, and requiring the use of increased applications and additional chemicals.