Mango phyllosticta leaf spot

Mango leaf spot, caused by the fungus Phyllosticta mangiferae-indicae, is a significant pathological condition affecting mango trees worldwide. As a deuteromycete fungus, it primarily targets the foliage, causing aesthetic damage and, in severe cases, reducing the tree's photosynthetic capacity by triggering premature leaf drop.

The host range is essentially limited to Mangifera indica. While the leaves are the primary sites of infection, the pathogen can sometimes affect floral panicles and tender stems, especially during prolonged periods of high humidity and rainfall, which compromises the overall yield of the tree.

The characteristic symptoms begin as small, circular to irregular necrotic spots. As the lesions expand, they turn light brown or greyish at the center, surrounded by a distinct dark, often reddish-brown margin. The appearance of tiny black pycnidia scattered across the surface of the lesions is a diagnostic feature used to identify this fungal infection.

The development and spread of Phyllosticta mangiferae-indicae are strictly dependent on environmental conditions. High humidity levels, prolonged leaf wetness, and temperatures between 20°C and 25°C provide the ideal climate for spore germination and colonization. Rain splashes are the main mechanism for the dispersal of spores within the canopy.

Disease management requires a combination of cultural practices and chemical intervention. Culturally, growers should maintain adequate tree spacing to ensure good airflow and prune trees regularly to keep the canopy open and dry. In orchards with a history of the disease, prophylactic fungicide applications, particularly copper-based fungicides, are recommended during the early stages of flush development.

• Implement proper canopy management and pruning.
• Clear away all infected leaf debris beneath the trees.
• Apply fungicide sprays when weather conditions favor disease spread.
• Ensure adequate tree spacing to promote air circulation.