Corn Standability Issues: 3 Management Tips

Many factors in crop production are out of your control. So it follows that the best way to manage your fields (and your stress level) is to focus on controlling the things you can to mitigate yield loss. 

Corn standability is the plant’s ability to stand upright and withstand challenging environmental conditions such as wind, drought, heat, insects and disease. In 2023, corn standability proved a challenging issue for growers who found themselves at the mercy of hot, dry conditions that led to pervasive stalk lodging. Extreme weather, in addition to insect and pest pressure, can have devastating effects on yield.

Corn standability issues at a glance 

Standability takes into account three primary factors: plant health, stalk strength and root health. The following issues contribute to the decline of corn standability.

• Stalk lodging: Corn stalk lodging is when the stalk breaks below the ear after the plant has reached physiological maturity. It reduces the amount of harvestable ears, with annual yield losses ranging from 5 to 25%.¹  
• Foliar disease: Foliar diseases reduced corn yield by an estimated 2.9% in 2023. Many common disease threats to midwest corn result in impaired plant quality and diminished stalk and root strength, leading to standability issues.
• Insect damage to stalks and roots: Foliar, root, ear and stalk feeding insects cause significant damage to corn plants. These common pest threats to midwest corn accounted for yield losses of over 5.2% across 27 U.S. states and a total loss of over 837 million bushels in the U.S. and Canada.² 
• Stalk rots: Stalk rot pathogens weaken stalks and increase their susceptibility to lodging when plants are exposed to wind or other stressors. 
• Root lodging: This occurs when the root system has been pulled from the soil and is especially damaging late in the season. If stalk elongation is complete and corn is nearly full height, recovery from root lodging is unlikely.
• Weather-related plant stress: Extreme weather conditions for corn can exacerbate already diminished standability from insect, disease or root rot damage. 

3 tips to manage corn standability issues and overcome harvest challenges

While some factors that contribute to corn standability issues are out of your control, controlling what you can is key. Implementing preventive, protective measures can reduce the decline of stalk integrity, and accurately assessing your corn standability prior to harvest can help you establish your harvest priorities, ensuring the highest possible yield for your conditions. 

Follow these three tips to manage standability issues and avoid unexpected problems at harvest.  

Tip 1: Scout the field for standability issues to determine at-risk fields

Corn becomes more susceptible to stalk rots and other diseases the longer it matures in the field. Prioritizing which fields to harvest first can be based on a simple scouting method. 

Conduct a push test by scouting in a W or X pattern, then push over the middle of stalks about 45 degrees; if more than 10% of stalks don’t spring back to fully upright, the field is at risk of lodging from an inclement weather event. These fields should be prioritized for harvest as soon as possible, especially when ears are well-filled and the plant is top-heavy. 

Scouting to understand the root cause (no pun intended) of standability issues is also helpful. Dig up several plants that show signs of weakness and compare them to healthy plants. Examine the roots and split the stalks with a knife to inspect the inside of the stalk. The roots of a damaged plant may display weak or very few roots, signaling the presence of a root rot pathogen³ or insect damage.

📸: Alison Robertson, Bugwood.org/ Featuring an image of corn roots affected by stalk rot

The stalk interior and crown may show discoloration if stalk rot disease is present. The interior of the crown should be white. A crown that is a tan to brown has some form of stalk rot present.

📸: Alison Robertson, Bugwood.org/ Featuring an image of the inside of a corn start showing signs of stalk rot



Additionally, drought conditions or severe foliar disease may present itself as cannibalized pith inside the stalk. Cannibalized pith occurs when severe stress causes corn plants to use up stalk sugars to feed the plant’s ear and kernels.⁴

You can scout for cannibalization in your cornfield by conducting a push or pinch test. A pinch test is done by pinching the stalk at the lower node; if it is easily crushed, the stalk has been weakened by cannibalization.

Tip 2: Adjust your harvesting method for fields with poor standability

You may be able to reduce yield loss in fields with compromised plant health and standability by adjusting when and how you harvest.

When to harvest corn with poor standability

Prior to harvest, assess which cornfields have the most significant signs of lodging, insect or disease damage, or diminished ear integrity (mold growth in the tip or interior of the ear, exposed ear tips or upright ears). These fields should be top priority for harvest. Also, if inclement weather is predicted, prioritize fields with poor standability that are more likely to be critically damaged by bad weather.

How to harvest corn with poor standability

When harvesting a field with lodged stocks, you can adjust your combine to pick up downed corn more effectively.

Ohio State University Extension recommends harvest adjustments including but not limited to:

• Operating the head as low as practical
• Using single-direction harvesting patterns to go against the grain of leaning stalks
• Adjusting gathering chains for more aggressive operation 
• Considering a corn reel to limit machine losses and allow greater travel speed and productivity
• Adjusting width of deck plates
• Reducing fan speed to avoid blowing kernels out of the combine
• Slowing the rotor speed to maintain grain quality

Tip 3: Use integrated disease and pest management to reduce plant stress

As mentioned previously, any additional stressors can contribute to standability issues (weather, pest and disease stress being chief among them). You can’t control the weather, but you can control pest and disease pressure.

• Foliar fungicides: Stressed plants can lead to stalk rots, and stalk rots can lead to stalk lodging. While foliar fungicides cannot directly prevent stalk rot infection, by promoting overall plant health and improved photosynthesis they can improve the plant’s ability to fight pathogens like stalk rots. 
• Cultural practices: Tillage can speed up the decomposition process of crop residue that may contain stalk rot pathogens. Subsequently, this reduces the risk of future infection by stalk rot pathogens present in the soil. Crop rotation is another cultural practice that can impact standability by reducing stalk and root damage from pests such as corn rootworm that thrive on corn-following-corn. By using crop rotation, you can help break the life cycle of these host-specific insects that attack corn plants.

Pesticidal and Bt control: Controlling insect pests, especially from corn rootworm and corn borer, is key to maintaining stalk and root integrity. A soil-applied insecticide such as Nurizma® insecticide is strongly recommended to control corn rootworm. Nurizma has been recently approved and is now available for growers. Because Nurizma is a unique mode of action for corn rootworm, it is an effective resistance management tool to help growers control corn rootworm populations that may become resistant to Bt traits and other in-furrow insecticides.

Corn borer damage can be prevented by avoiding very early or very late planting. Also, avoid early-maturing varieties. Consider planting Bt corn, which has proven effective at significantly decreasing borer populations in corn.  Fastac® CS insecticide is an option as a foliar application for corn borer control.

Experts are available to help you make your decisions. Reach out to your seed retailer, a nearby extension office agent, or a seed company professional like your regional BASF representative.

Learn more at Grow Smart® Live:

Learn more about how to navigate conditions that increase the risk of standability issues: 

• Unraveling the Impact: How Heavy Winds Affect Corn Growth and Yields
• Common Disease Threats to Midwest Corn
• Common Pest Threats to Midwest Corn: A Guide

Nurizma and Fastac are registered trademark of BASF.

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Endnotes

1. Nielsen, Bob. "Stalk Lodging in Corn: Guidelines for Preventive Management." Purdue Extension, www.extension.purdue.edu/extmedia/ay/ay-262.html. Accessed 16 June 2024.
2. "Corn Invertebrate Loss Estimates from the United States and Ontario, Canada — 2023." Crop Protection Network, 14 Feb. 2024, cropprotectionnetwork.org/publications/corn-invertebrate-loss-estimates-from-the-united-states-and-ontario-canada-2023. Accessed 9 July 2024.
3. Collins, Alyssa, and Adriana Murillo-Williams. "Evaluating Corn to Determine Harvest Priorities." Penn State Extension | The Pennsylvania State University, 4 Oct. 2023, extension.psu.edu/evaluating-corn-to-determine-harvest-priorities. Accessed 28 June 2024.
4. Wiersma, Daniel, and Ev Thomas. "There Are Cannibals in Your Cornfield." Hoard's Dairyman, 2 Sept. 2021, hoards.com/article-30843-there-are-cannibals--in-your-cornfield.html. Accessed 28 June 2024