Fire Blight on Loquat: Pruning and Streptomycin Protocol

Loquat tree shows fire blight symptoms. Owner asks for chemical treatment.

Fire Blight Reality

Loquat (Eriobotrya japonica) is in Rosaceae—highly susceptible to Erwinia amylovora (fire blight bacterium). Increasing problem on loquats, photinia, pears.

Immediate Action: Sanitation Pruning

1. Cut out ALL infected branches 12-18" below visible symptoms
2. Sterilize tools between cuts (10% bleach or 70% alcohol)
3. Remove debris completely—burn, bury, or bag for trash
4. Do not compost

Chemical Suppression: Streptomycin

• Product: Fertilome Fire Blight Spray (streptomycin sulfate) or agricultural streptomycin
• Timing: Begin at first bloom, repeat every 4-7 days through bloom
• Duration: Several months if pressure high
• Note: Antibiotic resistance risk—use only during bloom, rotate with copper if needed

Critical Cultural Rule

STOP FERTILIZING (especially nitrogen). Succulent new growth = highly susceptible. Slow, hardened growth resists infection.

Long-term Management

• Resistant cultivars if replanting
• Prompt removal of any new strikes
• Copper sprays during dormant/delayed dormant
• Avoid overhead irrigation

Fire blight is aggressive but manageable with diligence. Loquats are worth saving—beautiful trees, delicious fruit.