Lily of the Valley with Anthracnose: Prevention & Cure

Convallaria majalis

Susceptibility: Moderate Severity: High Difficulty: Easy

Anthracnose is a fungal disease caused by fungi in the genus Colletotrichum that affects many plants, including vegetables, fruits, and trees. The disease thrives in cool, wet conditions, causing dark, sunken lesions on leaves, stems, flowers, and fruits.

🔍 Symptoms

• Small irregular yellow or brown spots on leaves
• Dark sunken lesions on leaves, stems, flowers and fruits
• Water-soaked lesions that darken as they age
• Pink gelatinous masses of spores in lesion centers during warm, moist weather
• Spots that expand and may cover entire leaves
• Defoliation in advanced stages

❓ Possible Causes

→ Caused by fungi in the genus Colletotrichum
→ Cool wet weather promotes development
→ Optimum temperature between 75-85°F (24-29°C)
→ Foliage wet for extended periods of time
→ Fungi overwinter in seeds, soil and garden debris
→ Spores spread through water droplets

💊 Treatment

⚡

Quick Fixes

Remove and discard all visibly infected parts

Apply commercial systemic fungicide (azoxystrobin or mancozeb)

Adjust irrigation to avoid wetting foliage

Second application of systemic fungicide

Assess treatment effectiveness

🌿

Organic Treatment

Remove all infected plant parts and discard in plastic bag

Apply organic liquid copper spray to all plant surfaces

Switch irrigation regime to drip, avoiding foliage wetting

Second application of copper fungicide or neem oil

Assess progress and remove any new lesions

Final organic fungicide application and ongoing monitoring

🛡️ Prevention

✓ Implement drip irrigation instead of overhead watering
✓ Give plants enough room to breathe and reduce humidity
✓ Remove infected plant material after harvest
✓ Practice crop rotation between hosts and non-hosts
✓ Choose resistant plant varieties when possible
✓ Use western grown seeds not exposed to the disease
✓ Avoid wetting foliage during watering
✓ Ensure good air circulation around plants

🌱 Care Guide: Lily of the Valley

💧 How to Water

Water regularly to keep the soil consistently moist, especially during the spring growing season. Reduce watering once the foliage dies back in summer. Avoid waterlogging — ensure good drainage to prevent crown and root rot.

☀️ Lighting

Prefers partial to full shade. Protect from direct afternoon sun, which can scorch the delicate leaves. A spot under deciduous trees or on the north/east side of a building is ideal. Tolerates low light very well.

🪴 Ideal Soil

Plant in humus-rich, well-draining soil with a slightly acidic to neutral pH (5.5–7.0). Amend with compost or leaf mold to improve moisture retention and fertility. Avoid heavy clay soils that become waterlogged.

See more: Lily of the Valley → See more: Anthracnose →