Hail Damage and Yield Loss

Goof Demo - Hail Damage and Yield Loss

Good Demo - Hail Damage & Yield Loss

Corn crop injury due to hail occurs somewhere in the United States each year. In those areas, growers must assess the damage. In this goof demonstration, Pioneer simulated hail damage and evaluated the severity of crop injury.

V5 Hail Damage Simulation

V5 Hail Damage Simulation

In this section of the hail damage goof demo, plants were whipped with a wire flag to simulate hail damage at the V5 growth stage.

V8 Hail Damage Simulation

V8 Hail Damage Simulation

Whipping the plants with a wire flag was also the method to simulate hail damage at the V8 growth stage. The photo on the left shows two corn plants from the same demo - one with simulated hail damage and the other with no hail damage.

VT Hail Damage

Early VT - Hail Damage

The top left photo shows the plots just prior to imposing the VT hail damage. The photo on the bottom left shows corn (middle rows) at the VT stage with simulated hail damage. The photo on the right is a close up of the damage imposed at VT.

Yield Loss

Ears with V5 hail damage, V8 hail damage and VT hail damage

This photo clearly shows the correspondence between the plant growth stage and timing of the hail damage and ultimately yield loss. Jeff Mathesius, Pioneer agronomy research manager, provides estimated yield losses based on the timing of the hail and corn growth stage.

V5: When hail occurs at this growth stage, it's early enough in the season that the growing point is still protected below ground, resulting in little, if any yield loss.

V8: When hail damage was simulated at this stage about 75 percent defoliation occurred. Much of the growing season remains at this point and because the growing point was not damaged and many new leaves are still emerging, yield loss was estimated at about 6 percent.

VT: At the VT stage tassels are emerging and if the tassel is destroyed, yield potential can be severely limited. There is also the potential for hail to strike the developing ears at this stage and destroy ovules. At this stage, Pioneer imposed about 90 percent defoliation and also destroyed a number of tassels in the process. Pioneer agronomists estimated there would be about 80 percent loss in yield in this demonstrated scenario.

Review a chart - Estimating Yield Loss from Defoliation

Mathesius notes that hail damage also can potentially cause bruising on stalks at any stage, which can lead to a higher incidence of disease and pest damage as the season progresses and in turn result in additional yield losses.

Use this information as a guide and it should not be the only factor in making decisions.

Total Corn Yield Loss from Hail Damage

Estimating Yield Loss from Defoliation

Total corn yield loss from hail damage is estimated by adding the expected yield loss caused by stand reduction, the expected loss caused by defoliation, and the expected loss caused by direct ear damage. These numbers are only an estimate of the percent yield loss. As with undamaged corn, extremely favorable weather during the rest of the growing season can cause actual yields to be higher than expected. Similarly, unfavorable weather can cause greater-than-anticipated reductions.

Use this information as a guide and it should not be the only factor in making decisions.