Arrested Ear Syndrome

Well, it has shown up again – perhaps the worst we’ve seen in at least several years. I’m talking about arrested ear syndrome (also called blunt ear or beer can ear).

I prefer the term arrested ear syndrome because I think that best describes the phenomenon. The corn plant develops apparently normally, including full length husks, but the ear development stops at some point. The result is an ear which is full-sized in terms of girth but may be from 2 to 6 inches long. The tip of the ear, where the cob should have continued to develop, will have a small spike, perhaps the diameter of a pencil lead and about 3/8 inches long. This small spike is the cob that did not develop properly.

No one that I’ve found knows exactly what causes the cob, or ear, to develop normally for some time, and then to stop before it has reached its normal length. One theory is that a significant change in temperature in a short period of time (probably a drop from a warm spell to quite chilly) will cause cell development at that point in the ear to stop – hence “arrested ear”. If this is the cause, it must happen fairly early in the growing season as the cob length is being determined (V6-V12). Growth chamber studies at Purdue have been unsuccessful in reproducing this suspected chilling injury (personal communication with Dr. Bob Nielsen, Purdue Agronomist).

A second possible cause is in-season application of a pesticide and/or additives (MSO, COC, etc.). This has been observed in the field and has been reproduced by Purdue researches, so it is pretty well accepted as one cause of arrested ear.

However, there are plenty of known cases in which there was no post – emergence application so there must be an environmental cause in at least some of the cases. Drought is not suspected – this syndrome is different than the typical short ears found in severe drought conditions.

There has been some suspicion that it may be related to a certain genetic family of hybrids, but arrested ear has been found in a wide variety of hybrids, including those from numerous companies and numerous known different genetic backgrounds.

If you find arrested ears, or short, stubby ears in your fields, we’d like to know it. Please phone or email if you find this problem in any of your fields.

Here is a link to Dr. Bob Nielsen’s recent article on this topic. It includes some excellent photos of the problem.

http://www.agry.purdue.edu/ext/corn/news/timeless/BluntEars.html

If you have any questions or concerns please contact:

Terry Jones CPAg, Regional Agronomist @ 419.346.7786 or


or

Rod King CCA, Regional Agronomist @ 574.596.6721 or