Thursday, May 19, 2011

Everyone is Talking about Corn that has Turned White......

There have been several reports of corn turning white in different parts of Illinois. 

One of those reports from Southern Illinois (not yet confirmed at the U of I Plant Clinic)  refers to the possibility of Holcus spot in corn.  Holcus spot is caused by a bacterial pathogen and can be easily confused with paraquat (herbicide) injury.  Holcus spot is difficult to diagnose because the bacteria may not be readily found within the lesion.  Holcus spot has a wide host range and can infect foxtail millet, pearl millet, Sudan grass, broom corn, Johnson grass, wheat, and sorghum.  This disease is not a major problem in corn, but it is not commonly found.  For additional information, you can go to:   http://cropdisease.cropsci.illinois.edu/corn/holcusspot.html

These are pictures of suspect Holcus spot or paraquat injury from another sample that was previously submitted to the U of I Plant Clinic:

Now, the next issue that is causing "quite the buzz" among agronomists and consultants is the issue of corn turning white in the field.  I was lucky enough to find a case of this and I did take pictures.  I am not sure what may be causing this and I am unable to investigate further on this particular case, as I do not have any information on what chemicals (herbicide or insecticide) that have been applied to or near this corn field.  This picture was taken in a field south of I-72.  There does not seem to be a pattern.  As you can see in the pictures below, these plants were found in areas of the field that had been waterlogged.




 
Dr. Aaron Hager,
Associate Professor of Weed Science, has had a few reports of this, but is not sure there has been anything consistent in each instance.  Some wonder about herbicide injury (which is possible), although there have been reports of this occurring in fields where no herbicide as yet been applied.  He suspects the weather/wet soils might also be contributing to this.




You are always welcome to submit a sample to the U of I Plant Clinic, where we and Dr. Hager will fully examine the white, corn plants.  We will also need a very extensive history of the field, which includes all chemicals applied to the field.

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