Source: Doug Jardine, Extension Plant Pathology, Kansas State University

When corn is planted back into corn residue, producers should be aware of the increased potential for certain diseases. Not all diseases are affected by cropping systems, however. The following is a brief summary of how soil and leaf diseases differ between continuous corn and rotated corn.

Soil diseases
* There is a greater probability of developing lesion nematode problems in continuous corn.

* Root rots, such as Fusarium root rot, could potentially be more severe. Root rot often develops into stalk rot. Root rots are also weather dependent, so just being in continuous corn does not necessarily lead to more root rot every year.

Leaf diseases
* Gray leaf spot could be more of a concern, since the disease overwinters on corn residue.

* Goss's wilt could also be more of a concern since the disease overwinters on corn residue.

* Ear rotting pathogens such as Diplodia, Aspergillus, and Gibberella thrive on corn residue, and may be increased in continuous corn systems. Keep in mind that in addition to yield loss, some ear rots produce dangerous toxins such as aflatoxin and vomitoxin.

* Southern corn rust and common rust will not be affected one way or another by being in continuous corn vs. a crop rotation. The rust diseases blow in from southern areas every year and do not overwinter in Kansas.