Midwestern corn growers know the symptoms of northern corn leaf blight all too well: greenish-gray lesions on the leaves that can add up to major yield losses if not detected and treated early. Resistance genes have been identified in corn, but the fungal disease has found ways to sneak around corn’s defenses. Now, researchers have figured out how the fungus is outsmarting corn, and they may be able to use this information to help corn fight back.