Fusarium wilt of mango

Fusarium mexicanum is a filamentous fungus belonging to the Fusarium fujikuroi species complex. It is a highly significant plant pathogen known for causing Fusarium wilt in mango trees. By invading the xylem of the plant, the fungus restricts the vascular system's ability to transport water and nutrients, eventually leading to the rapid wilting and death of the host plant.

The primary host for this pathogen is the mango tree (Mangifera indica). While first identified in Mexico, its presence has implications for global mango production. The fungus is capable of surviving as mycelium or chlamydospores, allowing it to persist in the soil for extended periods even in the absence of a host plant, making it a difficult pathogen to eradicate once established in an orchard.

Symptoms of the disease are typically observed in the canopy, starting with chlorosis and the drooping of leaves on individual branches. As the vascular infection progresses, the foliage turns necrotic and the branches dry out. A diagnostic feature is the vascular browning visible in cross-sections of infected twigs and stems, which is a result of the plant's defense response against the fungal colonization.

The development and spread of Fusarium mexicanum are largely driven by moisture and temperature. High soil moisture facilitates the infection of root systems, while mechanical injuries on the trunk or branches serve as entry points for the pathogen. Once introduced into an orchard, it can spread through contaminated tools, runoff water during irrigation or heavy rains, and the movement of infected soil on equipment.

Effective management strategies require an integrated approach. Since chemical control is often limited by the systemic nature of the fungus, prevention remains the most effective tool. This includes strict phytosanitary measures, such as the use of pathogen-free nursery stock, the sterilization of pruning equipment with bleach or alcohol, and the removal and destruction of infected tree parts to reduce the inoculum level in the environment.