May 18, 2004
Evaluating Hail Damage to Crops and Replanting Decisions
Late in the evening of Monday, May 17, 2004, several locations received hail of various sizes and densities. When this occurs early enough in the season that re-planting is an option, careful evaluation of the situation and re-planting options is crucial.
I am not aware of any corn in the counties I cover that is advanced enough that the growing point is above ground; the growing point reaches ground level when the first six leaves have totally emerged (V6). Unless the hail hit hard enough that it penetrated the soil far enough to hit the growing point, the corn should recover fully. Generally, some new growth will be seen within 3 - 4 days of the hail. Injuries may provide an entry point for diseases, so the plants should be watched closely for several more days, however.
Soybeans, on the other hand, have the growing point(s) above ground from emergence on. Plants cut off below the cotyledons (thick bottom seed leaves) will not regrow. If plants are broken off above the cotyledons, there is a bud in the axil between the cotyledon and stem and between the unifoliolate and trifoliolate leaves and the stem; these buds will produce new growth. It takes about 4-7 days to see re-growth on soybeans after hail. As with corn, injuries may provide an entry point for diseases, so continue to watch the plants closely.
Several resources are available to help in evaluating the injury and deciding to keep or re-plant the crop. They are
"Evaluating Hail Damage on Soybeans and Corn" (a two-page (one-page front-and-back) handout)
"Evaluating Hail Damage on Soybeans" (text from the above handout)
"Evaluating Hail Damage on Corn" (text from the above handout)
Several other resources are available at http//www.extension.iastate.edu/newsrel/hail.html
If you have any questions, please feel free to contact the Iowa State University Extension Office.
Last Update: May 18, 2004
Contact: Virgil Schmitt email@example.com
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