Beer Can Ears Make an Appearance

Greg Roth
Department of Crop and Soil Sciences
Penn State

An image of blunt ear syndrome in corn

Recently, Extension Agent Del Voight has reported two separate fields showing the blunt ear syndrome or "beer can" ears in Lebanon County. These are ears that are characterized by a relatively normal husk covering, some silkballing and noticeably stunted cob development. The result is a short ear with maybe 10 rows of kernels instead of the normal 35-40 rows and usually a short segment of cob that has not been pollinated due to the failure of some silks to emerge. We don't really know what causes the problem, but it appears to be more prevalent following springs that had some cool temperatures that may have caused some chilling stress to the plants. I expect we'll see more of these this year following the cool spring we had. In some of the past years where I've seen this there has been a weak relationship with some hybrids. In some cases it's scattered in the field but in a few cases nearly the whole field can be affected, with serious effects on yield. Dr. Bob Nielsen, my counterpart at Purdue University has a graduate student who is studying this problem and is trying to document the situations where the problem has occurred. Bob and his student have prepared a downloadable survey form: http://www.kingcorn.org/research/beercan/FieldInfoform.pdf for folks who are willing to share the background on a field showing these symptoms. If you find a field, please consider sharing the data on it with Bob.