Fruit Rot and Cane Botrytis

Botrytis cinerea

14 host plants · Fungal

Last updated

Data Maturity Structured

This profile synthesizes data from multiple published sources. Expert field review is in progress.

Gray mold develops on raspberry fruit at harvest, and you see watermark lesions on canes in late summer. Botrytis cinerea drives wet-weather losses exceeding 50% during bloom and harvest. Manage by improving canopy air circulation, pruning to reduce density, minimizing nitrogen, and harvesting in cool morning hours. Select resistant cultivars like Munger or Meeker.

No single cultural practice provides adequate management of gray mold under highly conducive conditions. Integrate several tactics to manage this disease.

Quick Reference

Agent Type
fungal
Causal Agent
Botrytis cinerea
Host Plants
14
Spread
Wind-dispersed conidia (primary); rain-splash and irrigation water dispersal;...
Favorable Conditions
4-6 hours continuous leaf wetness at 60-77°F (15-25°C); optimum 65-73°F. Free...

Management

Vulnerability Window

Bloom period (bud break through post-bloom); fruit development and ripening in cool, wet weather; early post-harvest period. Extended wet periods from late spring through summer and during mechanical harvest.

What Triggers Infection

4-6 hours continuous leaf wetness at 60-77°F (15-25°C); optimum 65-73°F. Free water or very high humidity (>90%) required for spore germination and infection. Wet weather (rain, heavy dew, fog, overhead irrigation) during bloom and fruit development critical for early-season disease. Fruit maturity increasingly recognized as critical timing for infection and symptom expression. # Source: PNW Plant Disease Management Handbook

Cultural Controls

  • No single cultural practice provides adequate management of gray mold under highly conducive conditions.
  • Integrate several tactics to manage this disease.
  • The use of cultural tactics reduces reliance on fungicide applications and can help manage fungicide resistance. 'Munger', 'Chilliwack', 'Comox', 'Fairview', and 'Meeker' have shown moderate resistance to Botrytis fruit rot.
  • Create an open plant canopy: use a double top wire training system, prune, avoid excessive nitrogen fertilization, and control weeds.
  • These practices improve air circulation, increase light penetration, and speed drying of plant surfaces after irrigation and rain.
  • Avoid excessive nitrogen fertilization.

Host Plants (14)