Growing conditions this season have set the stage for potentially severe lodging, and with the strong winds late last week, lodging problems are starting to show up in some fields. Lodging risk is high this year because of the wet spring followed by some prolonged dry weather during grain-fill, as well as pest and disease pressure in some fields.
|This field experienced severe root lodging.|
During the past week I have seen fields suffering from extensive root lodging and stalk lodging. Root lodging is occurring because plants did not develop a strong root system during the wet conditions that followed planting in most fields. In some fields the already poor root systems were then subjected to moderate-to-severe rootworm damage. Dry conditions during grain filling tend to further erode the condition of roots, which begin to prematurely die and become rotted by soilborne fungi. These fungi then move up into the stalk and cause stalk rot.
Stalk lodging risk is higher this year because the combination of a wet spring and dry summer predisposed the plants to stalk rot susceptibility. I began to see stalk rot symptoms during mid-to-late August, including basal stalk rot and anthracnose top dieback. As of August 31, I noticed numerous fields in southwestern Iowa where all the plants were prematurely dead, due to moisture stress and stalk rot. These fields are now in danger of having substantial lodging problems if they are not harvested soon. I also have noticed that corn borer injury seems to be generally more extensive than in the past couple of years and this injury will contribute to lodging as well.
|Anthracnose top dieback.|
|Anthracnose top dieback symptoms.|
It is important to be aware of the stalk conditions in each cornfield and to make harvest plans for fields with stalk rot or other stalk quality problems. Timely harvest can avoid the lost time and yield occurring with badly lodged fields.
This article originally appeared on page 177 of the IC-486(22) -- September 17, 2001 issue.