Aureobasidium zeae

Systematic position and pathogen type. Aureobasidium zeae is a fungus belonging to the family Dothioraceae within the order Dothideales and the phylum Ascomycota. It is classified as a specialized phytopathogenic fungus that exclusively targets maize (corn) crops. In agricultural science, it is recognized as the causal agent of eyespot disease, a significant fungal infection that impacts corn yield and plant health.

Diseases and host plants. The primary disease induced by this pathogen is corn eyespot. The infection is characterized by small, circular lesions on the leaves, which feature a translucent or necrotic center surrounded by a distinct yellow or brownish halo, resembling an eye. While primarily affecting leaves, the disease can also spread to leaf sheaths and husk tissue under high-pressure conditions.

Biology and life cycle. The pathogen overwinters as mycelium or conidia on infected corn debris left in the field. During the spring, favorable environmental conditions (moisture and moderate temperatures) stimulate the production of conidia. These spores are disseminated via wind and rain splashes to the lower leaves of emerging corn plants, initiating the infection process, which continues to spread upwards as the season progresses.

Developmental conditions and harmfulness. Aureobasidium zeae thrives in cool, humid conditions, particularly during the vegetative growth stages of corn. Temperatures ranging from 20°C to 25°C combined with frequent leaf wetness are optimal for the pathogen's development. The resulting damage reduces the photosynthetic capacity of the plant, leading to stunted grain filling, reduced kernel quality, and significant potential yield losses.

Protection and control measures. To manage Aureobasidium zeae effectively, agricultural producers should utilize an integrated pest management approach:

• Planting resistant or tolerant corn hybrids is the most effective preventative measure.
• Removing or deep-plowing crop residues to reduce the initial inoculum level.
• Implementing crop rotation to eliminate the host environment for the fungus.
• Applying systemic fungicides during periods of high humidity and visible disease pressure to limit spread.