Breadfruit leaf spot

The disease is caused by the pathogenic fungus Pseudocercospora artocarpi, an Ascomycete fungus specialized in colonizing the foliage of tropical trees. It is categorized as a foliar fungal spot disease, which primarily affects the photosynthetic capacity of the plant by causing tissue necrosis.

The primary host for this pathogen is the breadfruit tree (Artocarpus altilis). While trees of all maturity levels can be affected, young, vigorously growing saplings and trees within dense, unmanaged orchards are particularly susceptible to severe outbreaks due to high humidity levels within the canopy.

The symptoms of the infection are visible as distinct spots on the leaf blades. Initially, these spots are small and often angular, gradually turning brown or dark grey as the tissue dies. A distinctive sign of the disease is the presence of fungal mycelium and conidia visible as a dark, dusty growth on the underside of the affected leaf spots.

The epidemiology of Pseudocercospora artocarpi is highly dependent on climate conditions. Persistent high humidity, tropical rainfall, and temperatures between 24°C and 28°C provide the ideal environment for spore germination and infection. Transmission occurs primarily through wind-borne spores and rain splashing, which facilitate the spread of the pathogen throughout the canopy.

The impact of this disease is significant, as severe defoliation weakens the host, leads to reduced fruit size, and can eventually stunt tree growth. Sustainable management strategies include:

• Sanitation practices, such as the systematic removal and destruction of fallen infected foliage to reduce the primary inoculum source.
• Improving orchard aeration through proper spacing and light pruning of the tree canopy.
• Application of appropriate fungicides, such as copper-based sprays, during periods of high disease pressure.