Brown Rot
Monilinia fructicola, Monilinia laxa, Monilinia fructigena
Overview
A destructive fungal disease of stone fruits and some pome fruits, causing blossom blight, twig cankers, and fruit rot. Infected fruit becomes mummified and can persist on the tree through winter. Brown Rot spreads mainly by spores on wind, splash, tools, and crop debris. Humid, crowded plantings and overhead watering favor outbreaks in home gardens and food forests. Causal agent: Monilinia fructicola, Monilinia laxa, Monilinia fructigena. In regenerative gardens, prioritize sanitation, airflow, and unbroken soil cover over calendar spraying, and intervene early when symptoms appear.
Symptoms
Blossoms wilt and turn brown (blossom blight). Small, sunken cankers on twigs. Fruit develops soft, brown, expanding rot with grayish-tan sporulation in concentric rings. Mummified fruit persists on tree. Compare several plants and note whether symptoms spread after rain, insect feeding, or wet foliage. Photograph undersides of leaves and cut stems when wilt is present to refine the diagnosis. Rule out simple drought, fertilizer burn, and herbicide drift before assuming a pathogen - abiotic injury often mimics disease.
Environmental Conditions
Humid
Prevention
Remove mummified fruit from trees and ground. Prune to improve air circulation. Thin fruit to prevent contact. Apply preventive fungicide at bloom and pre-harvest. Plant resistant varieties. Mulch to reduce splash, clear season-end debris, and avoid working plants when wet. Design beds for airflow and diverse plantings that support beneficial insects without creating permanent humid pockets around susceptible crops.
Management
Apply sulfur or copper fungicides at pink bud, full bloom, and petal fall. Remove infected blossoms and fruit immediately. Prune out cankers. Harvest fruit promptly and refrigerate. Prefer drip irrigation, morning watering, and open spacing so leaves dry quickly. Disinfect pruners between cuts on woody plants. Use copper, sulfur, or biological products only as labeled protectants when pressure is high - they rarely reverse advanced infections alone. Destroy (do not casually compost) highly infectious debris.