Powdery Mildew on Caragana: Identification and Fungicide Control

Symptom Match

White chalky coating on leaves appearing suddenly in summer = classic powdery mildew (fungal disease). Recurring annually suggests favorable microclimate (shade, poor air flow, humidity).

Disease Details

• Appearance: White/gray powdery growth on leaves, stems, flowers.
• Progression: Patches enlarge, merge; leaves curl, yellow, brown, drop early.
• Impact: Rarely fatal but reduces vigor, aesthetics, and winter hardiness.
• Favored by: Cool nights, warm days, high humidity, crowded plantings.

Fungicide Program (Start at First Sign)

Application Keys

1. Spray both leaf surfaces thoroughly.
2. Use spreader-sticker for coverage.
3. Repeat on 7–14 day schedule (more frequent in cool, damp weather).
4. Rotate chemical classes to prevent resistance.

Cultural Suppression

• Prune for air circulation.
• Avoid overhead watering.
• Remove fallen leaves in autumn.
• Plant resistant varieties if available.