Corn Lodging

042913_2028_HaveILostAn2Over the last week I have been seeing areas of lodging and general weaker stalks in some corn fields.  Lodging is the process where a corn stalk breaks below the cob.  There are multiple factors that contribute to lodging:Stalk Cannibalization
Prior to black layer, the corn plant will respond to stress by moving sugars from the stalk and leaves to the ear.  This is the plants method of maximizing potential yield.  As these sugars are removed, the pith cells which give the stalk strength, break down and result in a weaker stalk which are more prone to lodging.

Stalk Rots
Stalk rots infect the stalk and degrade the tissue.  Anthracnose, diplodia, fusarium and gibberella all work in slightly different processes to rot the stalk.  As the stalk rots it loses strength and become susceptible to lodging.
a                                                                                                            b

Anthracnose                                 Lodging In 2011

 
Fertility
Areas of the field with poor fertility can be more prone to lodging.  Potassium is important in the development of the pith cells.  At lower soil levels, the stalk strength can be weaker.  Other fertility issue including Magnesium, Calcium and ph usually result in smaller plants and weaker stalks.

Ear Development and Weather
As mentioned earlier, anything that adds to the weight of the plant puts more stress on the cob.  Cobs that remain high in moisture and/or carry a high kernel count, add weight to the top of the plant and make it top heavy.  The addition of wind, rain or snow further adds to the weight.  At a critical point the stalk will fail and lodge.  This critical point gets lower as the season gets later.

Scouting
Start by checking for rot.  A healthy stalk will be firm and if squeezed will not compress.  Stalks with rot, apart from showing visual signs of mold will feel soft and will compress easily.  If 10-15% of stalks show affects from rot, there is a chance of significant lodging.  Also preform a push test to check stalk strength.  Take 10 plants in a row and push them at shoulder level 6-8”.  If more than 10-15% of the stalks break below the cob, there is an increased chance of lodging.
Lodging can be devastating at harvest.  Cobs near the ground will not dry as quickly, they are more prone to ear mold and harvesting speed and efficiency can be seriously reduced.  Be aware of the fields and varieties that are higher risk and be ready to harvest those first or earlier is conditions start to deteriorate.