Integrated Crop Management

Disease prospects for lodged corn

Last week's storms flattened many acres of corn in parts of the state, and now there is much speculation about the future of these fields. There will be a variety of consequences to the corn's prostrate position, including an increased risk for some diseases. Most reports indicate that the lodging was mainly root lodging, not green snap, and so I will limit my comments to root-lodged plants. I expect that the physical injury the plants experienced will lead to increased incidence of common smut, both in the ears and other plant parts. Additionally, some of these fields will not pollinate well, and smut will probably be a particular problem in those fields.

If the ears remain in proximity to the soil, there also is likely to be a greater incidence of ear molds, because soil will be splashed onto the ears. Keep in mind, though, that ear rot pathogens are commonly airborne anyway, so the risk for low-lying ears may not be greatly increased.

Finally, the biggest impact may come from stalk diseases. Root damage that occurred as the plants lodged will probably result in greater incidence of stalk rots in some fields. Premature death of the plants as a result of the root damage and stalk rots will further reduce yields.

There is little or nothing that can be done to prevent these disease problems on the lodged plants. Remember that I am referring to the risk of increased disease; thus, these events will not necessarily occur in every field of lodged corn.

Lodged corn

Todd Vagts (ISU Extension field specialist-crops) in a field of downed corn near Kiron.

This article originally appeared on page 145 of the IC-488(18) -- July 22, 2002 issue.


Source URL:
http://www.ipm.iastate.edu/ipm/icm//ipm/icm/2002/7-22-2002/lodgedcorn.html