Mango leaf spot fungus

Pestalotiopsis mangiferae is a fungal pathogen classified within the Ascomycota phylum. It is widely recognized in tropical and subtropical agriculture as the primary agent responsible for leaf spot diseases and post-harvest fruit rot. This fungus demonstrates a broad host range, primarily affecting fruit-bearing trees and various ornamental foliage plants.

The disease primarily manifests on leaves and fruits. On leaves, symptoms include irregular brown or necrotic spots, often surrounded by a chlorotic halo. As the infection progresses, these spots coalesce, leading to severe defoliation. In fruits, the pathogen causes sunken, dark lesions that compromise the fruit's integrity, significantly reducing marketable yield and shelf life after harvest.

The life cycle of the fungus is driven by the production of conidia, which act as the primary inoculum. These spores are disseminated via wind, rain splashes, and human activity during orchard maintenance. The fungus persists in the environment by colonizing necrotic tissue, leaf litter, and mummified fruits, remaining viable through unfavorable seasons until environmental conditions trigger new infections.

Environmental conditions such as high humidity (above 80%) and temperatures between 25°C and 30°C are optimal for the proliferation of Pestalotiopsis mangiferae. Stressed or physically damaged plants are highly susceptible to colonization. Dense tree canopies that restrict airflow exacerbate the problem by maintaining a humid microclimate, facilitating rapid spread across the orchard.

Effective management requires an integrated approach that focuses on orchard hygiene and chemical intervention. Recommended control strategies include:

• Regular pruning and destruction of infected twigs and leaf litter to reduce spore density.
• Ensuring proper orchard drainage and spacing to improve air circulation.
• Application of protective copper-based fungicides or systemic triazoles during peak infection windows.
• Monitoring irrigation practices to avoid excessive leaf wetness, which promotes spore germination.