Cercospora leaf spot of tung tree

The causative agent of this disease is the fungus Mycosphaerella aleuritidis (anamorph stage: Cercospora aleuritidis). It is a well-known pathogen that specifically targets the foliage of tung oil trees, impacting their photosynthetic capacity and overall physiological health.

The primary hosts for this pathogen are members of the Aleurites genus, especially Aleurites fordii. Cultivators of these trees in humid subtropical regions must be vigilant, as the fungus is capable of causing significant economic losses in commercial plantations.

The visual symptoms of the infection include the appearance of distinct circular or angular spots on the leaves. These spots typically start as small chlorotic dots, eventually turning brown or necrotic, and often develop a visible mold-like layer of conidia on the leaf underside.

Disease progression is heavily dependent on environmental conditions, particularly high humidity, frequent rainfall, and moderate warmth. These factors trigger the germination of spores, which are then disseminated via wind and splashing water, allowing the disease to spread rapidly through the orchard canopy.

Management strategies for this fungal pathogen center on integrated pest management practices. These include the removal and destruction of infected plant debris, which acts as the primary inoculum source for the following season. Additionally, applying copper-based fungicides during the early stages of the growing season is effective in limiting the impact of the disease.