Longan with Anthracnose? Rare but Treatable

Dimocarpus longan

Susceptibility: Low Severity: High Difficulty: Medium

Anthracnose on Longan: What to Know?

Anthracnose on Longan (Dimocarpus longan) is a fungal condition with high severity. Longan has low susceptibility to this disease. 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...

Longan is a medium-care plant. Recovery from Anthracnose takes approximately 14 days with proper treatment.

Unlike most plants, Longan has natural resistance to Anthracnose. Best treated with preventive measures rather than reactive treatment. Unlike bacterial infections, Anthracnose on Longan can be managed with organic fungicides.

🔍 What Does Anthracnose Look Like on Longan?

• 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

❓ What Causes Anthracnose on Longan?

→ 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

💊 How to Treat Anthracnose on Longan?

TLDR: Treat Anthracnose on Longan with quick treatment (~7 days) or organic (~14 days). Longan has low susceptibility to this disease.

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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

🛡️ How to Prevent Anthracnose on Longan?

TLDR: Prevent Anthracnose on Longan with 8 essential preventive care practices.

✓ 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

🌱 How to Care for Longan to Prevent Anthracnose?

💧 How to Water

Water once a week, thoroughly and evenly, ensuring water reaches deeper roots. During the dry season, before flowering, reduce watering—this encourages flower bud differentiation. Avoid overwatering: longan is sensitive to waterlogging, which quickly leads to root rot. After fruiting, resume regular irrigation.

☀️ Lighting

Longan needs full sun for at least 6–8 hours daily. Insufficient light significantly limits fruiting and weakens the tree. Plant in an unshaded location, away from taller buildings and trees. In cooler climates, place it in the warmest, sunniest spot in the garden or against a south-facing wall.

🪴 Ideal Soil

Fertile, well-draining sandy-loam soil with a pH of 5.5–6.5 is best. Longan does not tolerate heavy and waterlogged soils—if necessary, improve drainage by adding perlite or coarse sand. Mulching around the trunk helps retain moisture and regulate soil temperature.

Frequently asked questions

Can Anthracnose kill my Longan?

Yes, without treatment, Anthracnose can be fatal to Longan. Early detection and treatment are key.

How long does Longan take to recover from Anthracnose?

With proper treatment, recovery takes approximately 14 days. Without treatment, it can take significantly longer.

Is Anthracnose contagious to other plants near Longan?

Yes, Anthracnose can spread to nearby plants. Isolate the affected Longan immediately.

See more: Longan → See more: Anthracnose →