Organic Way to Stop Brown Rot in Stone Fruit

Signs

• In the spring when blossoms are infected, the flowers generally do not fall off the tree but will appear wilted and brown. Inspect dead blossoms carefully to look for tan spores. The fungus will continue to spread, causing cankers to form on the twigs. Once the fruit grows on the tree, look at it closely. The fruit may contain soft, brown spots that continue to grow in size. The fruit may also become covered with tan spores. The stone fruits usually remain on the tree after they rot completely. The fruit that remains on the trees dries out or appears “mummified,” while the brown rot spores continue to infect new growth.

Sanitation

• Remove all dried and infected fruit from the trees and the ground. Bury the rotten fruit in the ground away from the trees or orchards. West Virginia University suggests dumping the rotten fruit in more than one location to minimize disease and insect outbreaks. Remove branches that show signs of cankers. Canker sections contain wilted leaves, discolored bark and dark sections. Burn the pruned branches, if possible, to destroy the brown rot spores.

Pruning and Thinning

• Thin fruits early in the season to prevent the spread of brown rot. Then them four weeks after they bloom, spacing the fruits around 6 to 8 inches apart on the branches. Prune the stone fruit trees to help the air circulate. Good air circulation helps dry foliage quickly and it allows the sunlight to penetrate the branches. Remove large branches and upright shoots from the center of the tree. For best results, prune the trees using the open center pruning system to allow light to contact all the branches.

Tips

• Always discard fruits that have brown spots or signs of rot. Inspect the stone fruit trees again in the spring to look for blossom infections and cankers. Remove infected shoots and damaged branches from the tree. If you cannot successfully eliminate the brown rot with organic methods, you may have to resort to chemical fungicides. The trees may need spraying two or three times to control blossom infections.