Corn: Ear Rot or Moulds

Excerpt from Agronomy Guide for Field Crops (Chapter 3)

Order OMAFRA Publication 811: Agronomy Guide for Field Crops

Table of Contents

1. Ear Rot Management Strategies
2. Diplodia Ear Rot
3. Fusarium Ear Rot
4. Gibberella Ear Rot
5. Updates on Corn: Ear Rot or Moulds
6. Related links...

Ear Rot Management Strategies

White moulded corn may or may not contain toxins, but pink or purple moulded corn will likely be contaminated. Any of the Fusarium rots can establish after pollination in wounds created by insects or birds. Warm rainy weather or long dews any time after pollination may lead to ear rots in these wounded cobs.

The green (Penicillium) and black (Cladosporium or Alternaria) moulds do not normally pose a probl0; however when found in great abundance, they may put livestock off feed. Development of ear rots is stopped when corn is dried or ensiled, but the level of harmful toxins already present will remain unchanged. Where corn is stored in cribs, these fungi will continue to grow under favourable weather conditions. The fungi will continue to produce toxin until corn moisture drops below 20%. See the OMAFRA Factsheet, Controlling Fusarium Mycotoxicoses in Swine, Order No. 90-066, or visit the Web site at www.omafra.gov.on.ca/english/crops.

Preventing ear rots and mould is difficult since weather conditions are critical to disease development, and although some tolerant hybrids are available, none have complete resistance. Crop rotation can reduce the incidence of Diplodia. Cultural practices have been shown to have limited success in preventing ear and kernel rots. Minimize these diseases through timely harvest and proper drying and storage.

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Harvest fields that have 10-15% stalk rot early. This will minimize losses due to stalk breakage or lodging.

When ear rot is present, the following storage and feeding precautions are advisable:

• Harvest as early as possible.
• If bird damage is evident, harvest outside damaged rows separately. Keep and handle the grain from these rows separately.
• Adjust harvest equipment to minimize damage to corn. Clean corn thoroughly to remove pieces of cob, small kernels and red dog.
• Cool the grain after drying.
• Clean bins before storing new grain.
• Check stored grain often for temperature, wet spots, insects and mould growth.
• Control storage insects.
• Exercise caution in feeding mouldy corn to livestock, especially to hogs. Pink or reddish moulds are particularly harmful. Suspect samples should be tested for toxins.
• Avoid cribbing corn with pink ear rot.

See Appendix F, Laboratories Equipped for Feed Testing for a list of laboratories.

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Updates on Corn: Ear Rot or Moulds

No updates available at this time.

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Related links...

• Diseases
• Corn
• Field Crop Protection Guide - Publication 812

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