A Herbicide Application Strategy for Crops by Growth Stage and Weed Pressure Weeds are not a side problem in farming, they are one of the biggest, most preventable causes of yield loss worldwide. Left unmanaged, weed competition for light, water, and nutrients can reduce crop yields by 30 to 60 percent, depending on the crop and the severity of infestation. Yet most yield loss from weeds isn't caused by using the wrong herbicide, it's caused by using the right herbicide at th