Guava anthracnose

Guava anthracnose is a significant fungal disease caused by the pathogen Colletotrichum psidii. This pathogen is a classic representative of anthracnose-inducing fungi, primarily targeting the tissues of its host plant and causing widespread necrosis across fruits, leaves, and young branches.

The primary host for this pathogen is the common guava (Psidium guajava). The fungus thrives on plant tissues throughout the growing season, showing high host specificity and causing severe economic losses in tropical regions where guava is commercially cultivated as a fruit crop.

Symptoms of Colletotrichum psidii infection typically manifest as sunken, dark, necrotic lesions on the surface of ripening fruits. Under conditions of high humidity, these lesions become covered with masses of conidia that range from pink to salmon, which act as a source of secondary inoculum for further infection cycles.

The disease spread is heavily favored by warm temperatures, typically ranging from 20°C to 28°C, combined with high humidity and prolonged leaf wetness. Rain splashing and wind are the primary vectors for dispersing spores throughout the orchard, making canopy density and airflow management critical factors in disease development.

• Prune trees to improve air circulation within the canopy.
• Sanitize the area by removing and destroying infected plant debris.
• Apply copper-based fungicides or systemic chemical treatments during vulnerable growth stages.
• Monitor plantations closely during the rainy season to detect early symptoms.

Control strategies for this disease rely on an integrated approach. While cultural practices like sanitation and pruning significantly reduce initial inoculum, chemical protection is often necessary in high-pressure environments. Prophylactic fungicide applications are crucial during flowering and fruit setting to protect the harvest from infection.