Hops with White Mold: Prevention & Cure

Humulus lupulus

Susceptibility: Moderate Severity: High Difficulty: Easy

White Mold on Hops: What to Know?

White Mold on Hops (Humulus lupulus) is a fungal condition with high severity. Hops has moderate susceptibility to this disease. White mold (Sclerotinia sclerotiorum) is a devastating fungal disease affecting over 400 plant species worldwide. The fungus produces black, seed-like structures (sclerotia) that can survive in soil f...

Hops is a easy-care plant. Recovery from White Mold takes approximately 21 days with proper treatment.

Unlike bacterial infections, White Mold on Hops can be managed with organic fungicides. Without precautions, chemical treatments for White Mold can be harmful to pets. Use organic methods for Hops in pet-friendly homes.

🔍 What Does White Mold Look Like on Hops?

• Sudden wilting and yellowing of leaves
• Fluffy white mold growth on stems and leaves
• Water-soaked lesions expanding irregularly
• Soft, watery rot near soil level
• Black sclerotia (0.5-1cm) in white fungal mass
• Grayish-green appearance before wilting
• Infected stem sections become brittle and tan-colored

❓ What Causes White Mold on Hops?

→ Fungus Sclerotinia sclerotiorum surviving in soil via sclerotia
→ Prolonged cool, moist conditions (50-68°F/10-20°C)
→ High humidity during flowering period
→ Poor air circulation from dense planting
→ Wind-borne spores from germinated sclerotia
→ Direct contact with contaminated soil
→ Fungus survival on plant debris for 5+ years

💊 How to Treat White Mold on Hops?

TLDR: Treat White Mold on Hops with quick treatment (~11 days) or organic (~21 days). Hops has moderate susceptibility to this disease.

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Quick Fixes

Immediate removal

Remove and completely destroy all infected plants. Burn or bag and dispose in trash.

Apply fungicide

Apply systemic fungicide (SDHI or DMI) to neighboring healthy plants preventively.

Reduce moisture

Stop all overhead watering. Use drip only. Improve ventilation/drainage.

Isolate area

Create buffer zone by removing plants within 20-inch radius of infection.

Intensive monitoring

Inspect remaining plants 2x daily for 14 days.

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Organic Treatment

Remove infected plants

Carefully remove entire plant without spreading sclerotia. Burn or bury deeply (24+ inches). Do not compost.

Apply biocontrol

Apply Coniothyrium minitans to soil per instructions. This fungus parasitizes Sclerotinia sclerotia.

Improve circulation

Thin adjacent plants to improve airflow. Space plants 12-18 inches apart.

Adjust irrigation

Switch to drip irrigation. Water early morning. Avoid wetting foliage.

Soil solarization

If possible, cover soil with clear plastic for 4-6 weeks in summer (kills sclerotia).

Monitoring

Inspect plants daily for 3 weeks. Remove any new infection immediately.

🛡️ How to Prevent White Mold on Hops?

TLDR: Prevent White Mold on Hops with 8 essential preventive care practices.

✓ Plant with proper spacing to promote air circulation
✓ Avoid excessive irrigation during and after flowering
✓ Use drip irrigation instead of overhead sprinklers
✓ Remove and destroy infected plants immediately
✓ Implement crop rotation with 2-3 years of non-host crops (cereals, corn)
✓ Water early in day so foliage dries before nightfall
✓ Clean up all crop debris after harvest
✓ Avoid planting susceptible species in areas with disease history

🌱 How to Care for Hops to Prevent White Mold?

💧 How to Water

Water the hops thoroughly once a week, equivalent to about 1 inch (2.5 cm) of water per week. Ensure the water penetrates 8–12 inches (20–30 cm) into the soil. Let the topsoil dry out slightly between waterings to avoid rot. During dry periods and during cone development (August–September), more frequent watering may be necessary. Avoid overwatering—hops are susceptible to root rot in stagnant, wet soil.

☀️ Lighting

Hops thrive best in full sun and should receive at least 6–8 hours of direct sunlight daily. A sunny, warm, and sheltered location provides the best growth and largest cone yield. The plant tolerates light shade, but this will reduce cone production. Ensure good air circulation around the plant to prevent fungal diseases.

🪴 Ideal Soil

Plant hops in deep, nutrient-rich, and well-drained soil with a pH between 6.0 and 7.5. Loam or sandy soil with plenty of added compost is ideal. Hops have deep roots and benefit from loose soil. Avoid heavy clay that retains moisture. Enrich the soil with well-rotted compost or manure at planting and add nitrogen-rich fertilizer in early spring.

Frequently asked questions

Can White Mold kill my Hops?

Yes, without treatment, White Mold can be fatal to Hops. Early detection and treatment are key.

How long does Hops take to recover from White Mold?

With proper treatment, recovery takes approximately 21 days. Without treatment, it can take significantly longer.

Is White Mold contagious to other plants near Hops?

Yes, White Mold can spread to nearby plants. Isolate the affected Hops immediately.

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