Evaluating Hail Damage in Corn – It all Depends on Timing and the Severity of the Damage​​​

Each time I am called to evaluate a hail-damaged field, the same question is asked, “What type of yield loss can I expect?” Regardless of the plant development stage of growth, my answer is the same; “Depends on what happens for the rest of the season.”

The timing of the hail event is critical, along with the severity of damage. If the damage occurs in early June before the sixth leaf stage, the growing point is usually still protected beneath the soil surface. Complete above-ground defoliation can occur and if the growing point remains healthy, it can still emerge and provide a high chance of having a solid crop. Having said that, there are always exceptions. The level and severity of hail damage to the above-ground foliage can still impact the ability of the plant’s growing point to emerge.

Waiting a week to see how the crop is going to emerge after a severe hail event is often not an option as replanting in early June versus mid-June can mean a significant decrease in crop yield potential. Replanting after June 15th is not the greatest option for grain production as a reduction in yield potential (greater than 50%) can be expected unless chopping for silage is an option.

Also, adding extra population between the rows is not the best management decision when faced with a severe hail event as the newly emerging corn seedlings act as weeds, taking valuable nutrients and moisture away from the recovered stand. Again, this can greatly impact yield potential.

So, what are the options?

1. Assess health and stand of the impacted field.
   1. What is the population of viable plants with healthy growing points (this also applies to fields where the corn’s growing point has emerged)?
   2. My rule of thumb for a field impacted by hail during mid-to-late June is to leave the field if there are greater than 20,000 plants per acre.
2. If replanting is required and corn is the only option, work with your local Channel Seedsman to select an earlier product best suited to the expected GDU accumulation from time of planting to first killing frost for the area. Make sure to remove any existing damaged stand to ensure uniformity of replant. Note: There is more flexibility with product selection if you have a silage option. Also, consider other cropping options depending on any existing fertilizer and weed controls implemented to date.
3. If the best option is to keep the existing crop, continue to manage according to the original plan. Many growers decide to reduce in-season fertilizer applications, reduce herbicide programs, shut off irrigation options, etc. However, it is important to continue to do everything possible to maintain plant health moving forward as this can have a large impact on the crop’s ability to realize its yield potential.
   1. Consideration should be given to a fungicide application within a few days after the hail event. Hail-damaged foliage means easy entry for several corn diseases like anthracnose which can have a major impact on yield potential (Figure 1).
   2. The field should be monitored throughout the remainder of the growing season for additional needs.

One final note: The hail-impacted crop’s yield potential largely depends on the environment throughout the rest of the growing season. Moisture and heat availability, disease and insect populations, and additional environmental events could still impact product potential. We can only do our best to manage what we can.​​​​