Zinc and possibly certain other metals or their salts cause peanut stems to split open and may even kill plants after roots penetrate into soils having high concentrations of these elements. Toxic concentrations of such elements are frequently found in areas of fields where old buildings once stood or where livestock feeders were once located. Toxicity symptoms may appear a few weeks after planting or later in the season depending on the concentration and depth of toxic elements. At first, plants appear stunted and have yellow leaves. The split stem symptom is unique to this problem and serves as a diagnostic key for recognition.