Hail on Corn

June 6, 2011
ICM News

By Roger Elmore, Department of Agronomy

Corn progress is back on track thanks to recent warm weather. This is indicated by heat unit accumulation for May 1 planting dates hovering slightly above average (107 percent of average statewide). Corn development across the state ranges from about V2 to V9 (second to ninth leaf stages) thanks to the wide range of planting dates this year.

And then thunderstorms hit on June 9 and pounded the corn; some of the thunderstorms were accompanied by severe hail. Plant growing points are still underground for corn plants at V6 (sixth leaf stage) and younger. This fact helps the plants survive early-season hail events even if the leaves are totally destroyed. 

Be patient if your field has hail damage. The short-term weather forecast for warm and sunny weather plus the moisture received from the storms should encourage rapid and healthy regrowth. Plants V6 and younger should survive.  Assess more developed plants carefully.  The following links provide more detailed information:

Hail Industry staging systems differs

Be aware that hail industry corn staging systems differ from the leaf collar system most University Extension and researchers use. Table 2 in the Corn Growth and Development publication provides a comparison. (Click this to order publication on corn growth and development.)

In brief, the 'horizontal leaf' method used by the hail industry is about one to two stages ahead of the leaf collar  system from V2 to  V8. That means a V8 plant in the leaf collar system is similar to a V10 plant in the horizontal leaf system. This is important when you use tables like those included in the University of Nebraska publication referenced above.

Roger Elmore is a professor of agronomy with research and extension responsibilities in corn production. He can be contacted by email at relmore@iastate.edu or (515) 294-6655.


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