Mold and Test Weight in Corn

FOR IMMEDIATE RELEASE
October 29, 2009

This article will address two issues related to the current corn harvest season.

Much has been written and said about the fungal ear and stalk rots in corn. Diplodia ear rot has been widespread, and perhaps more prevalent than past years. Concerns have also been expressed about Gibberella and Fusarium ear rots. Moldy grain should always be tested before being fed to livestock. In Illinois, grain can be tested for mycotoxins at the Department of Agriculture's Centralia Animal Disease Laboratory; www.agr.state.il.us/AnimalHW/labs/centralialab.html The laboratory is located at 9732 Shattuc Road, Centralia, IL 62801, phone 618-532-6701. Additional information, by Carl Bradley, Extension plant pathologist, can be found in the University of Illinois Pest Management & Crop Development Bulletin, http://ipm.illinois.edu/bulletin/article.php?id=1233

Bob Nielsen, Extension corn specialist at Purdue University, recently commented about test weight issues in corn. Some points to consider include: (1) there is little research that indicates corn test weight is strongly correlated with grain yield, and (2) research does not support the belief that low test weight corn is inferior for animal feed quality. The cause of the low test weight may influence or determine if such corn is inferior or not.

Nielsen indicated the following common causes of low test weight corn.

· Test weight and grain moisture are inversely related. The higher the grain moisture, the lower the test weight.

· Other factors that contribute to low test weight are drought stress, late-season foliar leaf diseases such as gray leaf spot and northern corn leaf blight, and below normal temperatures in September. All these factors reduced the plants photosynthetic ability and resulted in less starch being deposited in the kernels.

· The early October frost/freeze damage to late-developing, immature corn stopped the grain-filling process.

· The occurrence of ear rots that damaged kernels resulted in light-weight, chaffy grain that has low test weights.

Nielsen's article can be found at this web site:

http://extension.entm.purdue.edu/pestcrop/2009/issue25/index.html#test

For more information in Ogle County call (815) 732-2191 or visit www.extension.uiuc.edu/ogle