When corn is planted back into corn residue, producers should be aware of the increased potential for certain diseases, said Doug Jardine, Kansas State Research and Extension plant pathologist. Not all diseases are affected by crop rotation, however.
The following is a brief summary from Jardine of how soil and leaf diseases differ between continuous corn and rotated corn.
- With continuous corn, there is a greater probability of developing lesion nematode problems.
- Root rots, such as Fusarium root rot, could potentially be more severe. Root rot often develops into stalk rot. Root rots also are weather dependent, so just being in continuous corn does not necessarily lead to more root rot every year.
- Gray leaf spot could be more of a concern, since the disease overwinters on corn residue.
- Goss’s wilt also could 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.