Variable weather can cause ear rots in corn. Some areas have received rain and cooler temperatures, while others have been extremely dry with consistently high temperatures. Regardless of your weather conditions, there are several fungi that can cause ear rot, resulting in lighter, poorer quality kernels. Some fungi can produce mycotoxins, which will potentially affect feed value and grain marketability.
During harvest, it’s important to identify fields that may have ear rots so you can create a plan to minimize rot impact on harvested grain.
Diplodia ear rot- Identification: Starts as white mold at the base of the ear and can cover the entire ear. The white, moldy kernels will also have raised, black bumps, known as pycnidia.
- Ideal environment: Cool, wet weather.
- Mycotoxin production: None.
- Management: Adjust combine settings to help discard the lighter, diseased kernels. Make sure grain is quickly dried to 15-16% to keep the disease from spreading in storage.
Diplodia Ear Rot. Source – SyngentaFusarium ear and kernel rot - Identification: A white to pinkish fungal growth on the kernels can cause “starburst” symptoms, which typically starts at the ear tip.
- Ideal environment: While this ear rot can occur under most weather conditions, it is most severe when weather is warm and dry.
- Mycotoxin production: Can cause mycotoxins, mainly impacting swine and equine.
- Management: Infected grain needs dried quickly and stored at 18% or less moisture.
Fusarium kernel and ear rot – starburst symptoms. Source: SyngentaGibberella ear rot- Identification: Distinguished by pinkish to red fungal growth on the tips of the ear. Silks and husks will sometimes stick to the ear when disease is severe.
- Ideal environment: Cool, wet weather (65-70° F) after pollination.
- Mycotoxin production: Produces 2 mycotoxins affecting livestock, especially swine.
- Management: Infected grain needs stored below 18% moisture to limit storage contamination. Test infected grain before feeding to animals.
Aspergillus ear rot - Identification: The fungus overwinters on soil debris and infects the kernels through insect damage. Spores on the end of the ear are yellow to olive green, with powdery mold usually between kernels.
- Ideal environment: Prefers hot and dry weather conditions, and spreads rapidly during drought conditions with high temperatures.
- Mycotoxin production: Produces aflatoxin, which can be toxic to livestock.
- Management: Stored grain should be dried quickly and periodically checked for mold growth. Test grain before feeding to livestock in severe cases of infection.
Certain hybrids are more susceptible to specific ear diseases, so consider planting trait options to better protect against insect feeding on the ear, as damaged kernels serve as an infection point for diseases. For help identifying ear rot diseases and more agronomic insights, contact your
Golden Harvest Seed Advisor.
Sources:
1. University of Missouri, Ear and Kernel Rots of Corn.
2. Crop Protection Network, Corn – Ear Rots, CPN-2001.
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