A tough fall for dropped ears
While crop scouting before harvest, I noticed several ears on the ground in a cornfield in southeast Indiana. Also, I received reports from other farmers about ears dropped in several fields.
Ear droppage doesn’t usually occur so early. What could be the reasons for early ear droppage this year? This is a year of extremes. Too much rain in the spring caused delayed planting, followed by a very hot and dry summer, which caused pollination problems in some fields.
We had anaccumulation of a lot of growing degree days in a short time. It speeded up maturity and may have affected proper development of the shank attachment.
Ear droppage may be caused by both genetic and environmental reasons. Corn breeders try to select against the experimental hybrids with a tendency to drop ears in order to eliminate the genetic component. However, some hybrids with very high yields and disease tolerance that tend to drop ears can slip into the commercial lineup.
• A combination of heat and stress impacted ear shanks.
• More ear droppage than normal was reported this year.
• Hybrids vary in the strength of shank attachment.
Severe heat and drought stress, as we experienced this summer, can also lead to ear droppage. Stress may affect the proper development of the shank that attaches the ear to the stalk.
European corn borer in conventional hybrids can cause ear droppage. The larvae of the second brood of borer tunnel into the shank and weaken the attachment of the ears, making ears prone to droppage.
In a hot and dry season, very fast drydown can occur and can lead to poor shank attachment. Sometimes, the shank gets pinched if there are a lot of aborted kernels near the butt of the ear, thus leading to poor attachment and droppage with strong winds.
How to limit ear drop
Walk your cornfields not yet harvested and notice if one hybrid is better than others in this regard. This is an especially good year to make selections because of the heat and drought stress, which can also cause ear droppage.
Check the shank attachment of each hybrid. Select those with the strong attachment with good ear retention characteristics.Select for hybrids that have greater tolerance to heat and drought stress. Yes, the 2011 growing season was tough, but we can learn a lot from it for the future.
European corn borers can also cause ear droppage in conventional hybrids. If you’re using these hybrids for grain premiums, make sure to control corn borers, if necessary, during the first brood. Otherwise, my advice is to use corn borer-resistant Bt hybrids. The Bt trait provides protection throughout the life of the plant.
Select for hybrids with tolerance to diplodia ear rot, the whitish fungus that usually starts at the base of ears and can cause ear drop. This disease also causes stalk rot. Learn from this growing season, and let’s hope for a great 2012.
Nanda is a crops consultant based in Indianapolis and director of genetics and technology for Seed Consultants Inc. Reach him at Nanda@seed
consultants.com, or call him at 317- 910-9876.
Lost yield: Yield loss adds up quickly when whole ears fall on the ground.
This article published in the November, 2011 edition of INDIANA PRAIRIE FARMER.
All rights reserved. Copyright Farm Progress Cos. 2011.