Gibberella and Fusarium Ear Rots

Gibberella ear rot can be diagnosed by the color of the fungal mycelium growing on a diseased ear of corn. The diagnostic pinkish-red mold originates at the tip of an ear and grows toward the base. It usually does not infect an entire ear. The husk of a diseased ear may stick to the kernels and be difficult to remove (Wise et al. n.d.). Sometimes the mycelium is pale pink, which can lead to this ear rot’s being confused with similar diseases, such as those caused by Diplodia and its grayish-colored mycelium (“Corn Insect and Disease Guide: Gibberella Ear Rot” 2014, VanDyk 2002). Gibberella species causing ear rots on corn will also produce small, dark perithecia on the kernels, stalk, or husk. Fusarium ear rot produces white, pale pink, or pale lavender mycelia. Unlike Gibberella, Fusarium does not produce perithecia. Fusarium ear rot is often associated with insect infestations such as thrips or corn earworms. It tends not to engulf an entire ear but to remain localized around insect feeding injuries. A visual diagnosis of these diseases using their symptoms and signs is easy to perform and without cost; therefore, serological or molecular detection methods for diagnosis, such Enzyme-Linked Immunosorbent Assay (ELISA) or Polymerase Chain Reaction (PCR), are seldom necessary. These tests require lab work, equipment, and materials, making them more costly and time consuming than a visual diagnosis.