Olive anthracnose

Olive anthracnose is a fungal disease caused by the pathogen Colletotrichum clavatum, a key member of the Colletotrichum acutatum species complex. This disease is recognized as one of the most destructive threats to global olive production, impacting both yield and the chemical profile of extracted oil.

The primary host for this fungus is the olive tree (Olea europaea). The pathogen specifically targets ripening fruit, although it can occasionally infect leaves, twigs, and flower clusters. It survives between seasons in mummified fruits and diseased twigs, which serve as the primary inoculum for the next crop cycle.

Symptoms typically begin as small, sunken, necrotic lesions on the fruit surface, which gradually expand and darken. Under favorable humid conditions, these lesions become covered with masses of orange-colored conidia. Severely infected fruits often drop prematurely or become completely mummified while still attached to the tree.

Environmental conditions are critical for the spread of the pathogen, with high humidity, rainfall, and moderate temperatures being the primary drivers of disease outbreaks. The conidia are disseminated primarily through rain splash and wind, making dense, poorly ventilated orchards particularly susceptible to rapid infestation.

Effective management strategies require an integrated approach. Essential practices include the implementation of proper pruning to increase airflow, the rapid removal of fallen fruit to reduce inoculum pressure, and the application of copper-based or systemic fungicides during the onset of fruit maturation to prevent infection cycles.