Late wilt of maize

Late wilt of maize is a destructive vascular disease caused by the soil-borne fungus Magnaporthiopsis maydis. This pathogen invades the plant through the root system, colonizing the xylem and disrupting the water supply, which results in the rapid wilting and premature senescence of the crop during the grain-filling stage.

The disease primarily affects maize crops. Under favorable environmental conditions, the infection can spread rapidly across a field, leading to severe stand depletion and significant economic losses for producers. It is considered one of the most critical diseases in maize-growing regions worldwide.

Key symptoms include the sudden drying of leaves, which occurs without the typical yellowing associated with other stresses. The stalks show discoloration, and when cut open longitudinally, the internal vascular tissue appears reddish or darkened. As the disease progresses, the entire plant turns grey and brittle, often causing lodging.

The fungus thrives in warm and moist soil conditions. Optimal temperatures for disease development range between 25°C and 30°C. The pathogen can persist in the soil or in infected plant debris for several seasons, making it a persistent threat that is difficult to eradicate once it becomes established in the field.

Integrated management is essential for controlling late wilt. This includes the deployment of genetically resistant maize hybrids, which is the most effective defense. Additionally, farmers should practice long-term crop rotation, ensure proper soil moisture management, and focus on the deep incorporation of crop residues to reduce the overall inoculum load in the field.