It Is a Good Time to Reassess Standing Corn
By Justin Petrosino, ANR Extension Educator
OSU Extension, Darke County  
October 26, 2011 

As you might have heard on the Tiger radio station last week, I will no longer be working for Extension as of November 4, 2011. I was hoping to announce it in a more personal manner than a radio broadcast of a news report but they beat me to it! I have enjoyed my time with Extension and have enjoyed Darke County enough to continue to call it home. I will be taking a position with Stewart Seed as the Sales Agronomist for Ohio on November 7, 2011. 

Now that we have the quasi-farewell (I’ll still be around Darke County) out of the way let’s get down to business. Soybean harvest progressed quite well this month leaving just a few fields to finish up in dry conditions. However, corn fields are a different story. My brother recently informed me that in Afghanistan corn harvest was wrapped up a few weeks ago.  That is not so in Darke County. It is a good time to reassess standing corn fields to see which fields take priority. 

With damp conditions in many fields stalk rots can continue to be a problem. There are two simple ways to check the standability of corn out in the field. The first way is to push on the stalk and see if it snaps, this will give and indication of what is about to break. The other method is to squeeze the stalk at several heights between your thumb and pointer finger. It will be very hard to crush a healthy stalk, but if the stalk is soft it might be an indication of a future break. If weak stalks are present make sure to harvest that field as soon as possible. 

While in the field keep an eye out for ear molds. Although hot and dry conditions persisted through silking we are still seeing some ear mold in the field. Here are some quick tips for identifying ear molds. If the mold is white to pinkish and starts at the ear tip and works its way down it is most likely Gibberella ear rot. If it is white and starts from the base of the ear it is Diplodia. A pink growth around a single kernel or multiple kernels anywhere on the ear is Fusarium. Ear tip damage can result in the green growth of Aspergillus or blue growth of Penicillium. For more information on ear molds and toxins, click here to check out the OARDC Plant Pathology website .

The last thing to be looking for in the field is weeds. If the field will be going to soybeans marestail is a major concern. If you spot marestail a fall application of glyphosate + 2,4-D followed by a spring application of glyphosate + 2,4-D + a PRE like Valor XLT or Authority First, will provide control of marestail for soybean. If the field will go to corn after corn, not a recommendation but it does happen, be sure to control winter annual weeds. In the spring green weeds act as an attractant for the black cutworm. As the adults fly in the females will lay eggs in the winter annuals. Controlling the weeds now or early in the spring will help minimize the chances of black cutworm damage to next year’s corn crop. The same application of glyphosate + 2,4-D will clear up a field in winter or spring. 

Keeping stand loss to a minimum is critical whether it is early in the season or at the end of the season. If several gaps of 4 to 6 feet occur in a row of corn a yield loss can be as high as 5 %. In a 150 bu/acre corn crop that is 7.5 bushels lost in an acre. At today’s prices it is worth the extra time in the field to identify which fields need priority for harvest and which need a fall herbicide application.