Diaporthe canker of fig

The causative agent of this disease is the ascomycete fungus Diaporthe cinerascens (anamorph Phomopsis cinerascens). It is a persistent pathogen capable of colonizing the host's cortical tissues, leading to the development of localized necrosis and progressive branch dieback.

The primary host for this fungus is the common fig (Ficus carica). While the disease can manifest on young, succulent shoots, it is most damaging when it reaches the main woody branches or the main trunk, where it interferes with the plant's vascular system, eventually leading to the loss of significant portions of the canopy.

Typical symptoms involve the appearance of depressed, dark brown lesions on the bark. As the disease advances, the bark often splits, and the affected areas become covered with black, erumpent pycnidia—the asexual fruiting structures of the fungus. Foliage on infected branches may show chlorosis or sudden wilting as the structural integrity of the limb is compromised.

High humidity, frequent rainfall, and mild temperatures are the primary environmental drivers for the development and spread of Diaporthe cinerascens. The fungus spreads predominantly through splashing rain, wind-blown spores, and contaminated pruning tools. Wounds left by pruning or insect damage serve as optimal entry points for the pathogen to establish infection.

Management strategies focus on strict orchard hygiene. Infected branches must be pruned at least 15-20 centimeters below the visible lesion, and all tools must be disinfected with alcohol or a bleach solution between cuts. Removing and destroying all infected debris is critical to reduce the local spore load, while promoting good tree vigor through proper irrigation and nutrition helps the tree naturally resist fungal invasion.