Agronomy •  2021-06-23

Common Corn Ear Rots

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Diplodia Ear Rot
(no mycotoxins)

Diplodia Ear Rot

  • Wet weather during grain fill and upright ears with tight husks promote Diplodia
  • Diplodia may cause ear rot, stalk rot or seedling blight
  • Corn is only known host
  • Wet weather plus moderate temperatures allow infection to occur if spores are present during early silking to two to three weeks after silking
  • Diplodia is highly dependent on quantity of infected, unburied corn residue (stalks, cobs and kernels)

Fusarium Ear Rot (produces mycotoxins)

Fusarium Ear Rot

  • Most common fungal disease on corn ears
  • Fungi survive on residue of corn and other plants
  • Most severe when weather is warm and dry
  • Disease enters ear primarily through wounds from hail or insect feeding
  • Scattered or groups of kernels are typically affected
  • Mold may be white, pink or salmon-colored
  • Infected kernels may turn tan or brown
  • “Starburst” pattern often associated with the disease

Gibberella Ear Rot
(mycotoxins may occur)

  • Infects other cereals – causes head scab of wheat
  • Overwinters in infected crop residue
  • Spores are spread from crop residue to corn ears by wind and rain splash
  • Infection of corn ears occurs through young silks
  • Infection favored by cool, wet weather during and after pollination (optimum temps 65 to 70º F)


Aspergillus Ear Rot
(mycotoxins may occur)

Aspergillus Ear Rot
  • Most common under drought conditions, high temperatures (80-100º F) and high relative humidity (85%) during pollination and grain fill
  • Gray-green, olive, yellow-green or yellow-brown powdery mold growth on and between kernels
  • Surface mold can develop anywhere on the ear
  • Symptoms are often found at damaged areas of ear