Question of the Week - Spider Mites

Photo last week of a speckled cotton leaf was spider mites. They are tiny pests that feed under the leaves but cause leaf damage visible on top. they love it sunny and hot so hopefully recent cloudiness and rain will help reduce their numbers. They usually occur or at least start out in certain areas of a field.  This week a corn question, we are getting ready to start field corn harvest next week. What is the problem with this corn plant?