Storm Damage - June 2026

The storm systems that moved across the state this week have brought wind, heavy rainfall, and hail. Below are resources to help assess crop damage following these storms.  

Wind damage 

Some corn fields have been left leaning or have been root lodged, depending on soil moisture, after these storm systems moved through.  These fields should stand back up within a few days. Most corn is between V4 and V10 stages, so yield losses from leaning corn should be minimal. Past research shows leaning or lodging in V10 to V12 corn may reduce yields by 2-6%. Corn at these growth stages should upright itself within several days. In addition to leaning corn, there have been some reports of greensnap or brittle snap in corn. These plants are a total loss.  

Flooding 

If you have flooding or standing water out in your fields, the question becomes: how long can crops survive underwater or in saturated soils?  

For soybeans, if a portion of the plant remains above the water level, those plants stand a better chance of survival. However, survival doesn’t mean there isn’t any yield loss. With most soybean fields in the V1 to V4 range, if soils are saturated for 2-3 days, yield losses could be up to 50%. Additionally, flooded soybean fields could see reduced nodulation on roots, especially if saturated conditions last longer than 7-10 days.  

For corn, air temperature and length of time underwater greatly impact plant survival and potential yield loss. If plants are underwater for less than 48 hours, the impact will be smaller, especially with cooler air temperatures. However, if flooding lasts 4 or more days, the chances of corn plants surviving greatly diminishes.  

As the waters recede, it will be important to evaluate how much of the crop was able to survive, and if there is a need for replant or filling in thinner stands.  

Additional flooding-related resources:  

• Flooding Impacts on Corn Growth & Development 
• Flooding Impacts on Soybean Growth & Development 
• Corn Replant Checklist 
• Soybean Replant Checklist 
• Disaster Recovery: Flooding 

Hail

For those that have hail damage, your first step is to contact your crop insurance agent. After reaching out to your crop insurance agent, we generally need to wait at least 5-7 days to evaluate regrowth on hail-damaged crops—it can be hard to wait.   

In V5 or smaller corn, regrowth over the next week should be visible and there should be negligible yield loss since the growing point would still be protected. If corn is V6 or larger, careful assessment of damage will be necessary to determine if the growing point is still viable and how plants will recover. Check for bruising on the stalks and how deep that bruising went.   

For soybeans, plant stems cut below the cotyledons will not regrow. Plants with leaf loss or stem breakage above the cotyledons stand a good chance of regrowing due to the axillary buds at each leaf axil on the stem. Soybean plants can endure some leaf loss this time of year with minimal effect on yield. Additionally, check soybean stems for bruising as well. Brusing on the stem can make that part of the plant weaker later in the season. 

Fields with significant hail damage will need to be monitored for weeds emerging later into the growing season. Remember to double check labels for crop growth stage restrictions, pre-harvest internals, and crop rotation restrictions for later season herbicide applications.  
 
Additionally, it is often asked if a foliar fungicide is needed to protect the remaining leaf tissue. The short answer is no. A common misconception is that hail-damaged crops will be at a higher risk for disease infection. Fungal diseases such as gray leaf spot, northern corn leaf blight and tar spot in corn, or frogeye leaf spot in soybeans, do not require wounding to infect the plant. This is unlike bacterial diseases that often infect the plant through open wounds. Remember, however, a fungicide has no effect on bacterial diseases. 

Additional hail-related resources:  

• Corn Growth Stages 
• Soybean Growth Stages 
• Hail on Corn in Iowa (IPM78) 
• Hail on Soybean in Iowa (IPM79)