Quick Queries on Corn

Denise McWilliams, NDSU/UM Extension Crop Production Specialist (from the MN Crop Newsletter)

1. Thinking about areas that I plan to plant corn next year, should areas where compaction problems showed up in fields this year be chiseled?

Subsoiling can reduce the soil compaction that has been created in the fields if the tillage is done when the soil is dry. Tillage done now or later in the fall should shatter the soil so that compaction is then only limited. A winter with much freezing and thawing can also help alleviate some problems with compaction, but remember that the winter must have several thawing-freezing cycles occur in order to create any breakup of compacted soil.

2. What causes corn plants to create an ear on top of the plant (where the tassel is)?

Crop genetics along with high fertility can cause ear development in the tassel. Also, hail or mechanical damage during early plant development may show more tassel ears! High light conditions on the right genetics can also reveal this trait. However, yields shouldn't decrease on these unusual plants.

3. What causes corn plants to create multiple ears at one node?

This again is caused by crop genetics, high fertility, and ample light. Lower populations within the field may also help reveal this unusual trait. Occurring more in certain sweet corn lines than in field corn, this trait rarely has more than the dominant ear show substantial yield. And, if conditions are good, the dominant ear will not show yield reductions! Usually the side ears are barren, have only a few kernels or may have other problems such as silk balling or lack of sync with the timing of tassel pollination. Multiple ears where all the ears are clustered together within individual as well as enfolding husks can create other problems. The structure can hold water and lead to the development of ear diseases or may be more attractive to insects that feed on ear silks. It is rare to find this trait encouraged in corn lines, however, it does exist. Hopefully, this trait will be mapped and held for possible use in the future. If plant development could be speeded up and multiple ears are produced without problems, wow what a yield potential!

4. What causes corn smut in fields?

Common smut is caused by disease introduction through early, vigorously growing, wounded plant tissue under the correct weather conditions (no consensus but rainy, humid weather is generally critical for infection). Resistant corn hybrids do exist and some studies indicate that resistant lines could be selected by evaluating the progeny of developmental materials test-crossed with susceptible varieties. However, incidence is usually low and sporadic. Often tillers show more problems with smut than main corn plants.

Co-Editors: Bill Hutchison, Department of Entomology, University of Minnesota, hutch002@tc.umn.edu
Jeanne Ciborowski, IPM Program, Minnesota Department of Agriculture, jeanne.ciborowski@state.mn.us
Cindy Tong, Department of Horticulture, University of Minnesota, ctong@extension.umn.edu
Production Editor: Suzanne Wold, Research Specialist, University of Minnesota, woldx018@tc.umn.edu

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Last Revised August 16, 2000.
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