How Good are the Roots on Your Corn Plants?

CORN ILLUSTRATED: Now is a good time to check on root size and health.

Published on: Jul 9, 2013

Why would you want to look at roots now? Agronomists say there are several good reasons. One is to assess the roots for rootworm damage. In the central Corn Belt, lightning bugs appeared in the last days of May to early June. Since that corresponds with the hatch of rootworm larvae, that's likely when the larvae first appeared too.

Some have forgotten about rootworms because they use genetic tools in corn and/or seed treatments to take care of it. However, that doesn't mean all rootworms will be controlled, experts say. It still pays to check for signs of feeding. By this time of year you could dig up a few plants, hold them over plastic and shake them, or put them in a bucket and watch them, and look for larvae to shake off or come to the top of the water in the bucket.

Roots matter: Note the poorly developed root system on the left where soils were more compacted.
Roots matter: Note the poorly developed root system on the left where soils were more compacted.

If corn rootworm larvae are in the field, there may be no remedy for this year, but you may want to rethink your control strategies for 2014. What you may want to do is scout once pollination starts to make sure that rootworm beetles aren't clipping silks less than one-half inch long while pollination is underway. If that happens then you can likely make money by spraying to control the beetles.

Another reason for checking roots is to see if some hybrids have more rooting ability than others. And of course, yield is the final test. The strongest roots in the world aren't a reason for growing that hybrid again if it isn't a top yielder.

Finally, roots may have been impacted by other factors, including soil compaction. The compaction can cause roots to bend here and there, and many result in s smaller root system as well. If it continues to rain you may see minimal effect from soil compaction and rooting. If it turns off hot and dry before the crop is finished, however, there could be a yield drop due to soil compaction.