War on weeds loses ground

摘要

With its jumble of leaves and pointy, green, flower spikes, the plant known as pigweed or palmer amaranth (Amaranthuspalmeri) isn't much to look at. But to farmers in the southeastern United States, it is a formidable foe. Having evolved the ability to withstand glyphosate, the main ingredient in Monsanto's popular herbicide Roundup, it now flourishes unchecked along-side crops such as cotton and soya bean that are genetically modified to be glyphosate tolerant.