Nectarine Brown Rot: Fungal Disease Management for Fruit Quality

Symptom Match: Brown Rot

Glenda's nectarines (thumb-sized) turning black and shriveling before freeze protection move. Classic Brown Rot (Monilinia fructicola) — nectarines more susceptible than peaches.

Disease Cycle

• Overwinters in mummies, stem cankers, infected peduncles
• Beetles/insects vector spores
• Infection: pink bud → bloom → petal fall → preharvest
• Fruit resistant during hard green stage; susceptible near maturity
• Enters through natural openings or wounds
• Rapid brown water-soaked lesions
• Pink mold (Trichothecium) invades lesions → further decay

Control Program

Fungicide Schedule

• Pink bud stage
• Full bloom
• Petal fall
• Preharvest (critical for post-harvest protection)

Cultural Practices

• Remove/destroy all mummies and infected debris in winter
• Prune for airflow and light penetration
• Thin fruit to reduce clustering
• Harvest carefully to avoid wounds

Homeowner Fungicide

Thiophanate-methyl — follow label directions for timing and rates.

Early-season infection causes fruit drop/cracking; late infection causes storage rot. Nectarines need more vigilant protection than peaches.