One of the main problems caused by the widespread use of herbicide-tolerant, genetically-engineered (HTGE) crops is the rapid emergence of weeds resistant to glyphosate. Farmers are responding to the spread of glyphosate - resistant weeds by making multiple applications of glyphosate, increasing herbicide application rates, applying additional herbicide active ingredients, and using deep tillage to bury weed seeds, as well as manual weeding. This essentially locks farmers into an herbicide treadmill, using herbicides that increase in volume and toxicity.