Scouting for Corn Stalk Strength

Temperatures have generally been cooler than usual during this year’s corn grain-fill period.  In addition, over the past 30 days, overcast, rainy conditions have predominated in some areas; whereas in other areas, particularly far western Kentucky, rainfall levels have been well below normal until recently.  Conditions such as these may reduce photosynthesis rates enough to cause reduced stalk strength (Figure 1).

Figure 1. Reduced stalk strength can lead to lodging. (Photo: Paul Vincelli, UK)

Figure 1. Reduced stalk strength can lead to lodging. (Photo: Paul Vincelli, UK)

Stalk rot fungi may also colonize weakened stalks, resulting in internal discoloration and degraded pith (Figure 2).  The highest-risk fields would be those with high plant populations.

Figure 2.  Degraded stalk rind and pith caused by the fungus Diplodia maydis. (Photo: Paul Vincelli, UK)

Figure 2. Degraded stalk rind and pith caused by the fungus Diplodia maydis. (Photo: Paul Vincelli, UK)

It is always a good idea to scout fields for stalk strength.  Scouting will help you select fields for harvest based on how strong the stalks are.  Harvest those with the weakest stalks first, before they blow down from a strong storm.

The easiest way to check for lodging potential is to walk through the field and, at about chest height, check a hundred plants by pushing the stalk approximately 12 to 15 inches from its vertical position.  A stalk that bends and fails to spring back is prone to lodging.  If 10 to 15% of the stalks in a field exhibit lodging potential, the field should be scheduled for early harvest.

 

By Paul Vincelli, Extension Plant Pathologist

 

 

Posted in Grains