DISEASES OF CORN - EAR ROTS

Several fungi are able to infect corn ears and lead to decay of corn kernels. Two common ear rots are shown in this photo. The two ears on the left are examples of Gibberella ear rot caused by Gibberella zeae, the same fungus that causes stalk rot of corn. The two ears on the right are examples of Fusarium ear rot, caused by the fungus Fusarium moniliforme. These two ear rots are similar in that both causal fungi produce large of amounts of whitish mycelium on the surface of infected kernels. The two diseases can be distinguished by noting the pattern of infection on the ear. In Gibberella ear rot, infection starts at the tip of the ear and moves toward the base. Typically the husk is also infected and fuses to the ear. In Fusarium ear rot, infection tends to be more uniform, with no real concentration at the tip. Also, fusion of the husk to the ear is relatively less common.

In general, ear rots are of concern because they can lead to yield reduction. In addition, many ear rot fungi, including G. zeae and F. moniliforme, produce toxic compounds (called mycotoxins) that can adversely affect any animal that consumes them. Toxic effects of mycotoxins in domesticated animals vary depending upon the mycotoxin consumed, but can include refusal to feed, loss of weight, vomiting, increased occurrence of liver tumors, loss of kidney function and abortion of fetuses. Some mycotoxins are carcinogens.