Genetically-modifed corn and soybean has been widely grown in the US over the past 15 years, and has been flowing unrestricted in the food chain. In the main this has been until now accepted by farmers and consumers. No longer. Here is a report that US farmers are confronting herbicide-resistant weeds that require more herbicides to control them (an impact widely predicted with the onset of GM technology), together with the loss of premiums to the non-GM markets of Europe. US consumers are demanding labelling, and General Mills, one of the largest US food companies, has begun to meet that demand. These trends will have seismic impacts on the world agri-food industry.