Disease management is necessary in any crop to protect yield. An integrated approach using several practices is usually recommended, according to Alison Robertson and Gary Munkvold, Department of Plant Pathology, Iowa State University. In corn production, the most commonly recommended disease management tactics include hybrid selection, rotation, residue management, and fungicide applications.
In corn-on-corn fields, since rotation is not being practiced, the potential for yield loss due to increased disease is greater. This is because many of the common corn diseases that occur in Iowa are caused by pathogens that survive on infected corn residues. Rotation to nonhost crops of the pathogen allows time for decomposition of infected crop residues, which deprives pathogens of a food source and exposes them to antagonistic endemic soil microbes.
Therefore, rotation helps to naturally eradicate many pathogens from the soil, decreases inoculum levels, and reduces the risk of disease development. Surface residues also modify the soil environment (cooler soil temperatures, higher soil moistures), which can affect disease development.
Can we mitigate disease risks in corn following corn? Yes, but it is going to take a little more thought, care, and attention than we may be used to. Getting into the field to scout for disease outbreaks will be necessary if economically effective management decisions are to be made.