What is brown rot?
Brown rot is a common fungal disease (Monilinia fructicola) that affects trees in the “stone fruit” category such as peaches, nectarines, plums, cherries, and apricots. Brown rot can be very devastating, causing the fruit to rot and twigs to become cankered.
Fruits infected with brown rot first appear with soft brown spots. As the infection grows quickly, the fruit becomes covered in a powdery mass of fungus. Wet weather conditions can increase the development of this infection.
Brown rot can survive the winter in twigs and fruits affected by the disease. If the proper steps aren’t taken to minimize brown rot in the winter, the fungus will continue to spread and create more damage in the springtime.
Prevention and Management
As with mostly all diseases that affect fruit trees, proper prevention and control requires year-round attention. Minimizing the spread of brown rot can be done by pruning out twigs showing canker and removing any affected fruits that are still on the tree or that have fallen to the ground. It is important to hot compost, burn or deeply bury these materials in order to ensure the disease will not spread.
Properly pruning trees in order to allow more air and light can be a great measure against brown rot, which thrives in damp, cool conditions.
Copper or sulfur fungicide (organic) can be sprayed before or after blossoming in spring as a stronger measure to prevent brown rot, but can also negatively affect beneficial micro-organisms. Spring holistic spray of compost tea and neem oil may also help reduce the problem while boosting the micro-ecology. It is important to read the labels on any products you use very carefully to ensure soil or plants are not damaged by excessive application!
Watch a quick video about how to spray fruit trees:
This edition of POP TIPS prepared with assistance from 2014 POP intern Tina Kalakay.