Monilia

Monilia is a genus of fungi responsible for causing blossom blight and fruit rot, commonly known as brown rot. This devastating disease significantly impacts the productivity of fruit-bearing trees by destroying both the floral parts during spring and the developing fruits closer to harvest.

Common hosts for Monilia include stone fruits such as cherries, plums, peaches, and apricots, as well as pome fruits like apples and pears. The fungus survives in mummified fruits and cankered twigs from the previous season, ensuring the cycle continues year after year.

Initial symptoms manifest as scorched-looking blossoms that wilt and brown rapidly. As the season progresses, fruit infection begins with small, soft brown spots that expand quickly. Eventually, these spots develop concentric rings of gray or buff-colored fungal spores, leading to fruit shriveling and mummification.

The infection thrives under high humidity, frequent rainfall, and mild temperatures, especially during bloom. Spores are dispersed through wind and splashing water, which rapidly spreads the fungus throughout the orchard, particularly in dense, poorly ventilated tree canopies.

Effective management requires an integrated approach that includes:

• Aggressive sanitation: removing all mummified fruits and dead wood during winter pruning.
• Improving air circulation through canopy thinning to reduce humidity around fruits.
• Applying preventive fungicide sprays during critical growth stages like bloom and fruit set.
• Maintaining general orchard hygiene to reduce the initial inoculum level each spring.