Asian Pear Bitter Pit: Calcium Deficiency Management in Fruit

Asian pears developing hard, sunken, corky spots penetrating the flesh indicate bitter pit—a physiological disorder from calcium imbalance, not a pest or disease.

Understanding Bitter Pit

Cause: Calcium deficiency in developing fruit despite adequate soil calcium. Calcium moves poorly in plants—requires active transpiration and competes with growing shoot tips.

Symptoms: Internal brown, dry, bitter lesions (3-5mm) → external sunken spots → skin discoloration (brown/black/red halos). Starts internally, becomes visible at harvest.

Cultural Management (Preventive)

• Prune summer growth: Remove suckers/water sprouts through mid-August—reduces calcium competition
• Avoid excess nitrogen: Promotes vegetative growth over fruit calcium allocation
• Consistent irrigation: Prevent wet/dry cycles that disrupt calcium transport
• Manage crop load: Thin fruit if excessive—large fruit + light crop = worse bitter pit
• Limit potassium/magnesium: High levels antagonize calcium uptake

Calcium Supplementation

• Soil: Agricultural lime (calcium carbonate)—lower magnesium than dolomite
• Foliar/ fruit: Calcium chloride or calcium nitrate sprays (commercial standard)
• Product example: Nutra-Plus Calcium 8% every 10-14 days during growing season
• Post-harvest: Calcium drenches reduce next season's incidence

Key Insight

Bitter pit develops internally weeks before external symptoms. Current-year fruit cannot be cured—management targets next season. The recent onset suggests a cultural change: increased vigor, irrigation change, or soil shift.