Brown rot of Japanese apricot

Monilinia mumeicola is a fungal pathogen primarily known as the causative agent of brown rot and blossom blight specifically targeting the Japanese apricot (Prunus mume). This fungus is a member of the Sclerotiniaceae family and is highly specialized, causing significant physiological stress and economic loss in susceptible stone fruit orchards.

The characteristic symptoms of the disease include the sudden wilting and browning of blossoms during the flowering stage, often followed by the dieback of young shoots. Infected plant tissues typically develop dense, grayish tufts of conidia, which serve as secondary inoculum and contribute to the rapid spread of the disease throughout the tree canopy.

Environmental conditions play a critical role in the development and spread of the pathogen. High relative humidity and cool to moderate temperatures during the bloom period create an ideal environment for spore germination and infection. Rain and wind facilitate the dispersion of spores from mummified fruits or infected twigs remaining in the orchard from the previous season.

The severity of the damage caused by Monilinia mumeicola is reflected in substantial yield losses and reduced fruit quality. Infected fruits may develop soft, brown lesions that eventually cover the entire surface, leading to rapid decay. If left unmanaged, the pathogen can weaken the overall health of the tree by causing chronic branch dieback.

Managing this disease requires a multifaceted approach focused on reducing the inoculum source and protective spraying. Effective control measures include:

• Regular pruning and removal of all infected twigs and branches.
• Removal and destruction of mummified fruits that persist on trees or the ground.
• Timely application of fungicides during the critical phenological stages, such as the pink bud stage and full bloom.
• Managing insect populations that cause fruit wounding, as these injuries provide entry points for the fungus.