Loquat scab

Loquat scab is a fungal disease caused by Spilocaea eriobotryae, which is a major concern for growers of Eriobotrya japonica. This pathogen belongs to the Ascomycota group and specifically targets the foliage, stems, and fruits, often causing significant aesthetic and economic losses.

The disease primarily impacts the loquat tree, particularly during stages of high susceptibility such as spring flush and fruit development. Younger, tender tissues are more prone to infection, which can lead to stunted growth and premature leaf drop if not managed correctly.

The symptoms of loquat scab include the appearance of small, round, olive-green to dark brown spots on the leaves and fruit. As the infection progresses, these spots often develop a velvety appearance due to the formation of fungal conidia. Infected fruit frequently becomes corky, deformed, and develops cracks, making it unsellable.

Environmental conditions play a crucial role in the disease cycle. The fungus thrives in humid environments, particularly with frequent rainfall or heavy dew. Spores are primarily dispersed by splashing rain and wind. The pathogen overwinters on infected twigs and leaf litter, acting as a reservoir for new infections once the temperatures rise in the spring.

To manage loquat scab, sanitation is of the utmost importance. Growers should:

• Prune and destroy infected twigs and branches.
• Remove and dispose of leaf litter to reduce inoculum levels.
• Apply copper-based fungicides during critical growth stages (before flowering and after fruit set).
• Ensure adequate tree spacing and pruning for better airflow and light penetration.