Quince brown rot

Pathogen and disease type. The pathogen Monilinia cydoniae is an ascomycete fungus responsible for a devastating disease of quince trees. It is highly infectious and attacks various parts of the plant, including flowers, young shoots, and developing fruit. The fungus overwinters as mycelium in mummified fruits and infected branches, creating a persistent inoculum source in the orchard environment.

Host range and damage mechanism. The primary host of this pathogen is the common quince (Cydonia oblonga). The fungus invades plant tissues, causing necrosis and rapid cell death. During spring, fungal spores are dispersed by wind and insects to emerging buds and blossoms, leading to severe blossom blight and shoot dieback.

Symptoms and identification. Initial symptoms include brown spots on leaves and flowers, which darken and desiccate rapidly. Infected shoots often show wilting and curvature. Young fruits develop dark brown, sunken lesions that gradually enlarge to cover the entire fruit surface. Under high humidity, grayish tufts of fungal spores appear on the surface of the infected tissues, which is a diagnostic indicator.

Conditions for development and economic impact. The development of Monilinia cydoniae is favored by cool, wet weather during the flowering period. Persistent moisture promotes rapid spore germination and infection. The economic impact is significant due to severe crop losses, reduced fruit quality, and the potential decline or eventual death of the trees if the infection is left unmanaged.

Protective measures and prevention. Effective management requires an integrated strategy:

• Strict sanitation, including the removal and destruction of infected shoots and mummified fruits.
• Cleanup and removal of leaf litter from the orchard floor to reduce primary inoculum.
• Maintaining proper tree spacing and pruning to improve air circulation and reduce humidity within the canopy.
• Strategic application of fungicides at the green tip and pink bud growth stages.
• Selection of resistant quince cultivars when establishing new plantings.