 waterhemp, palmer amaranth, and giant ragweed. Left undisturbed, they will become the most dangerous foes to corn plants. But in the early season, these weeds are at their weakest. Now is the time. A predator lurks. Sertain herbicide attacks, unleashing full residual power before weeds have a chance to emerge. Pre- or early-post application, they are hopeless against such effective chemistry. Sertain herbicide from BASF. Always read and follow label directions.