Brown rot

Brown rot, caused by the fungus Monilinia fructicola, is a destructive plant disease that primarily affects stone fruit crops. As an ascomycete pathogen, it is responsible for significant economic losses in orchards globally by infecting blossoms, twigs, and fruit.

The disease host range includes major stone fruit species such as peaches, nectarines, apricots, cherries, and plums. It is a highly aggressive pathogen that can infect plants during various stages of development, from the blossom phase to post-harvest storage.

Key symptoms include the appearance of small brown spots that expand rapidly, eventually covering the entire fruit. These lesions develop into characteristic concentric rings of grayish-brown fungal sporulation. Infected fruit often shrivel and become mummified, remaining attached to the tree or dropping to the ground.

The spread of Monilinia fructicola is heavily dependent on environmental conditions, specifically high humidity and moderate temperatures. Rain and wind facilitate the movement of spores, while wounds caused by insects or hail provide easy entry points for the pathogen to colonize healthy tissue.

The damage caused by brown rot is severe, leading to direct fruit loss and total quality degradation. Because the fungus remains viable in mummified fruit, it serves as an inoculum source for the following season, creating a persistent cycle of infection that is difficult to break without integrated management.

Effective management requires a multi-faceted approach involving cultural practices and chemical control. This includes the removal and destruction of all mummies, pruning out infected wood, and the application of fungicides during bloom and pre-harvest intervals to minimize decay risk.