Fusarium Ear Rot
Symptoms vary depending on the variety of maize, the environment and the severity of the disease. The disease typically develops late in the season and during storage. Diseased kernels with white, pinkish-colored mold are interspersed amid healthy-looking ones. The kernels may also show discoloration. They might turn tan or brown. The discoloration follows a radial pattern from the top of the kernel. If conditions are favorable for the development of the disease (warm and dry weather, presence of pests), ears may be completely colonized by the fungus and show abundant fungal growth. The entire ear appears withered and the kernel might be completely consumed. Grain yield is reduced. The fungus produces toxins, making the ear inedible.
The disease is caused mainly by the fungus Fusarium verticillioides, but other species of Fusarium can trigger the same symptoms. It survives on seeds, crop residues or on alternative hosts such as grasses. Spores are mainly transported by wind. It enters the corn ears primarily through wounds from hail or feeding damage from insects and birds, or injuries during field work. It germinates and gradually colonizes the kernels from the entry points. Alternatively, it can start to colonize the plant from the roots and move up the plant through systemic growth. Plants can get infected under a wide range of environmental conditions, but the symptoms become particularly severe when the weather is warm and dry and the plants have reached the flowering stage. It is the most common mold in maize.
Solutions based on the bacteria Pseudomonas fluorescens can be used as seed treatment and as spray to reduce the incidence of the disease, and the production of toxins
Always consider an integrated approach with preventive measures together with biological treatmetns if available. Fungicides applied early in the season can limit ear infection. Since the damage occurs in the ears, fungicides are not the most effective way to fight the disease. Consider controlling insect pests that injure the ears and favor the growth of the fungus.