Corn Ear Rots (Uncommon)

Penicillium Ear Rot (mycotoxins may occur) Nigrospora Ear Rot (no mycotoxins) Cladosporium Ear Rot (no mycotoxins) Trichoderma Ear Rot (no mycotoxins)

Penicillium Ear Rot (mycotoxins may occur)

Corn cob damaged by Penicillium ear rot.

Corn cob damaged by Penicillium ear rot.

Blue-green fungal growth on and between kernels usually near the ear tip is characteristic of this disease
Fungal disease of ears often associated with damage from insects or other physical injury
Infected kernels may become bleached or streaked
Common and damaging fungus of stored grain, and can grow on kernels with moisture greater than 18%

Nigrospora Ear Rot (no mycotoxins)

Corn cob damaged by Nigrospora ear rot.

Corn cob damaged by Nigrospora ear rot.

Kernels have a dark gray or black discoloration from fungal mycelium and spores, mostly at the base of kernels
Infection may first be noticed when cobs shred from the butt end during mechanical harvest
Usually more severe at the base of ears, and ears are often chaffy and lightweight
Affected ears are often from plants that have been weakened from frost, drought, root injury, leaf blights, stalk rots or poor nutrition

Cladosporium Ear Rot (no mycotoxins)

Corn cob damaged by Cladosporium ear rot.

Corn cob damaged by Cladosporium ear rot.

Kernels have a gray to black or greenish-black appearance, and sometimes a powdery mold growth is present
- Also causes black streaks on kernels
This fungal disease is often seen on ears damaged from frost, insects or other mechanical injury
Wet weather during ear maturation and delayed harvest may favor this fungal growth

Trichoderma Ear Rot (no mycotoxins)

Corn cob damaged by Trichoderma ear rot.

Corn cob damaged by Trichoderma ear rot.

Typical symptoms include a dark green fungal growth on and between husks and kernels, often involving the entire ear
Fungal disease of ears usually associated with injury to the developing ear, including damage from bird or insect feeding or other mechanical injury
- For this reason, damage is not found on every ear, but rather, is usually more scattered within a field