In maize, this disease is characterized by symptoms on both ear and stalk. Early symptoms are often visible on the tip of the ear as white mold, which over time turn pink or red. As the disease progresses, the discoloration extends to the rest of the ear, often between the husk and the grains. Infected ears may rot completely. Leaves on early-infected plants turn a dull greyish-green and start to wilt. The lower internodes soften and turn a tan to dark-brown. Later on, black specks may develop on the surface, which can be scratched off easily using a fingernail. A cut along the stalk will show shredded, discolored tissues, with a pink or red tinge. The main root gradually rot, turns brown and brittle. Plant may die prematurely and lodge.
Symptoms are caused by Gibberella zeae, a fungus that overwinters in plant residues and possibly also in seeds. Spores are produced during wet, warm weather and spread by wind and splashing water. Primary infection usually occur when a spore lands onto the silk and start to colonize the tissues. Other possible sources of infection are wounds in the roots, stalk or leaves. Birds and insects are particularly harmful because besides the carrying of spores or seeds, they also damage plant tissues. Cereals such as rice, sorghum, wheat, rye, triticale or barley can also be infected by this pathogen. Other plants may carry the pathogen without showing symptoms, thus serving as a source of inoculum.
There is no biological control practice against G. zeae available at the moment. Please notify us, if you know of any. Hot water baths may be used to rid seeds of any pathogen. Please check which temperature and times are best adapted to your needs.
Always consider an integrated approach with preventive measures and biological treatments if available. There are no fungicides currently available for managing Gibberella stalk rot in maize. Seeds may be treated with fungicides, especially when the area is significantly infested by G. zeae.