Quince brown rot

The causative agent of this disease is the ascomycete fungus Monilinia linhartiana. It is a specialized pathogen that primarily targets quince trees (Cydonia oblonga), causing significant damage to blossoms, shoots, leaves, and ripening fruits.

The disease affects the plant at various developmental stages. During the flowering period, the fungus enters the blossoms, leading to blossom blight and shoot wilt, which significantly reduces the potential fruit set. If left unmanaged, the infection spreads to the developing fruits.

Symptoms include dark brown necrotic spots on leaves and fruits. As the infection progresses, the tissues become soft and decayed. Under humid conditions, greyish-white fungal spore masses (conidial pustules) appear on the surface of the affected organs. Eventually, the infected fruits shrivel and turn into hard, black mummies.

Environmental conditions play a crucial role in the development and spread of the disease. Cool, wet weather during spring is ideal for spore germination and infection. The pathogen overwinters as mycelium within mummified fruits remaining on the tree or in cankers on twigs, which serve as the primary inoculum source the following year.

The economic impact of this disease is substantial, resulting in heavy crop losses and reduced fruit quality. Moreover, severe infections can weaken the host tree, making it more susceptible to environmental stress and other secondary pests or diseases throughout the growing season.

Effective management requires a combination of sanitation and chemical control. It is essential to prune and destroy all mummified fruits and infected twigs during the dormant season. During the growing season, timely applications of protective and systemic fungicides (such as triazoles or copper-based compounds) during the flowering stage are critical for disease prevention.