Shot Hole Disease (Coryneum Blight) on Stone Fruit: Sanitation & Dormant Sprays

Shot hole disease (Coryneum blight), caused by Wilsonomyces carpophilus, affects peach, nectarine, apricot, plum, almond, and flowering cherries. Reddish-purple spots (¼") on buds/leaves → brown centers fall out = "gunshot" holes. Overwinters in infected buds/twig lesions. Wet springs = severe. Prevention via sanitation and dormant copper/Bordeaux sprays.

Management

• Sanitation (key): Promptly remove/destroy infected buds, blossoms, fruit, twigs. Rake leaves under tree.
• Dormant spray: Bordeaux mix or fixed copper in late fall (after leaf drop). Label rates. Do not apply spring after growth starts.
• Additional sprays during prolonged wet weather (check label).
• Avoid overhead watering—splash spreads spores.

Shot hole is a disease of wet springs and dirty orchards. The grower who cleans every mummy and sprays copper in November has clean leaves in May. The one who doesn't gets the shotgun look.