Loquat phyllosticta leaf spot

The fungus Phyllosticta eriobotryae is the primary causal agent of loquat phyllosticta leaf spot, a fungal disease that significantly impacts the foliage health of the host plants. It is classified as a pathogenic fungus that survives in plant debris and infects fresh tissue during the growing season.

This pathogen specifically affects the loquat (Eriobotrya japonica). While it primarily targets mature and young leaves, it can occasionally manifest on stems, leading to weakened growth and reduced vigor of the tree if left untreated.

Symptoms typically begin as small, brownish spots on the leaves, which gradually enlarge into necrotic lesions. Within these infected areas, small black structures known as pycnidia develop; these are the reproductive organs of the fungus that release spores to spread the disease further.

Warm and humid environments are ideal for the development and rapid spread of the pathogen. Spores are dispersed through water splashes, wind, and contact, allowing the fungus to infect foliage quickly, especially after rainfall or during periods of high humidity which facilitate fungal germination.

The impact of this disease includes premature leaf drop and a decrease in fruit production quality. Management practices should include:

• pruning infected leaves and branches;
• maintaining good orchard sanitation by removing fallen leaves;
• applying copper-based or systemic fungicides during the early stages of disease emergence.