Brown Rot (DEPRECATED)
Monilinia fructicola and M
2 host plants · Fungal
Last updated
During bloom, look for wilted, blighted flowers that turn brown and mummify on the branch; this blossom blight phase is your first sign of brown rot on stone fruits and ornamental relatives in the region. The disease spreads to young twigs and fruit later in the season, especially during warm, wet weather when temperatures sit between 68 and 77 degrees Fahrenheit. Mummified fruit left on trees or fallen to the ground overwinters and serves as a disease reservoir for the next season.
Brown rot spreads fast in our spring weather, so focus on preventing conditions that favor it: good air circulation is your primary weapon. Space trees wide enough to dry quickly after rain, prune to remove dense growth, and avoid overhead watering that keeps foliage wet. Remove mummified fruit from trees and rake up fallen fruit promptly. Prune out infected twigs in late spring or summer while you can still see the canker; waiting until dormancy makes infected tissue harder to spot.
Quick Reference
Management
Full bloom period (primary risk window); early fruit development; post-harvest storage in cool, moist conditions. Spring weather during bud break through full bloom critical for disease incidence.
Warm, wet conditions during bloom period; optimum 68-77°F (20-25°C) with free moisture (rain, irrigation, dew). Conidia and ascospores germinate readily on wet flower tissue and new shoots. Infection requires free water or high humidity during bloom. Cold springs delay apothecial development; warm, wet springs accelerate disease. # Source: PNW Plant Disease Management Handbook
Cultural Controls
- Rake and destroy infected leaves and mummified fruit to reduce spread of disease.
- Remove mummified fruit remaining on the tree, as well.
- Prune out infected twigs in late spring or summer.
- Do not wait until the dormant season, when infected twigs are difficult to distinguish.
- Space plantings and prune to provide good air circulation.
- This will reduce the moist conditions favoring disease.