Fungal Severity: High ⚠️ Contagious

Canker: Urgent! How to Save Your Plant

Canker is a disease caused by various fungi and bacteria that create necrotic, sunken areas on bark of branches, stems, and trunks. Pathogens enter through wounds and natural openings, especially when plants are stressed. Canker can gradually weaken or kill branches by disrupting water and nutrient flow.

Spread speed

Slow

Recovery time

90 days

🔍 Symptoms

Main Symptoms

! Sunken, discolored lesions on bark
! Oval to elongate dark areas on stems and branches
! Bark splitting and cracking
! Sap or resin oozing from infected areas
! Blackened inner bark tissue
! Progressive branch dieback beyond lesion
! Wilting foliage above infection site
! Small raised fruiting bodies on bark surface
! Complete girdling of stems and branches
! Yellowed, curled, or sparse foliage

Visual Signs

Sunken, discolored lesions on barkOval to elongate dark areas on stems and branchesBark splitting and crackingSap or resin oozing from infected areasBlackened inner bark tissueBranch dieback beyond cankerWilting foliage above infection siteSmall, raised fruiting bodies on bark surfaceGirdling of stems and branchesYellowed or sparse foliage

Affected parts: StemRootsWhole plant

❓ Possible Causes

→ Fungal infection by Cytospora, Phomopsis, Nectria, and Botryosphaeria genera
→ Bacterial infection by Pseudomonas syringae
→ Pathogen entry through pruning wounds, mechanical damage, or insect injuries
→ Plant stress from drought, transplanting, or winter damage
→ Extreme temperatures and adverse environmental conditions
→ Improper cultural practices weakening the plant
→ Bark wounds serving as entry points for pathogens
→ Poor species selection for local conditions

💊 Treatment

⚡

Quick Fixes

~45 days

Identify and mark all branches with canker

Use colored tape to mark affected areas

Prune infected branches 6-8 inches below lesion

Use sterilized tools; do on dry day

Immediately apply copper fungicide to wounds

Copper-based products are most effective

Dispose of all infected material in sealed trash

Do not leave on ground or compost

Spray systemic fungicide on entire plant

Thiophanate-methyl or propiconazole

Second systemic fungicide application

Follow label instructions

Inspect for new symptoms

Prune immediately if finding new cankers

Final evaluation and preventive application

Continue monthly monitoring

Materials needed:

Copper-based fungicideThiophanate-methylCommercial wound sealerTebuconazolePruning sawSprayerProtective gloves

🌿

Organic Treatment

~90 days

Carefully inspect entire plant identifying all cankers

Use flashlight to examine bark for sunken lesions

Prepare clean pruning tools and 70% alcohol for sterilization

Sharp pruning shears and saw for larger branches

Prune all infected branches 6-8 inches below visible lesion

Do on dry day; sterilize between cuts

Apply bordeaux paste to pruning wounds

Protects against reinfection

Dispose of infected material in sealed trash

Do not compost diseased material

Spray neem oil on entire plant

Apply in late afternoon; repeat every 14 days

Apply compost tea to soil around plant

Strengthens immune system

Second neem oil application

Continue biweekly for 2 months

Inspect for new cankers and prune if necessary

Monitor especially areas near old lesions

Evaluate overall health and adjust irrigation and fertilization

Reduce stress to prevent recurrence

Final inspection and preventive bordeaux mixture application

Apply before rainy periods

Continuously monitor and maintain proper cultural practices

Prevention is the best strategy

Materials needed:

Bordeaux mixtureOrganic wound sealer pasteNeem oilPropolisCinnamon powderSterilized pruning saw70% alcoholBrush

🔬

Expert Treatment

~135 days

Complete diagnosis: identify specific pathogen if possible

Send sample to lab for causal agent identification

Map and document all lesions with photos and location

Create detailed record for monitoring

Strategic pruning: remove severely affected branches

Cut 8-12 inches below lesion; sterilize between cuts

Scrape superficial trunk cankers to healthy tissue

Only for accessible cankers; constantly disinfect tool

Apply specific fungicide/bactericide to wounds

Use specific product based on lab diagnosis

Implement drip irrigation to reduce stress

Maintain consistent moisture without waterlogging

Systemic fungicide application via foliar spray

Thiophanate-methyl + propiconazole tank mix

Soil analysis and pH and nutrient adjustment

Correct deficiencies that may be stressing plant

Second round of pruning emerging new cankers

Continue rigorous sterilization protocol

Application of biostimulants and humic acids

Strengthens plant immune response

Complete reassessment: compare with initial documentation

Adjust strategy based on progression

Preventive application of copper + sulfur

Before rainy period or active growth

Trunk injection of systemic fungicide (if available)

Professional procedure for severe cases

Intensive monitoring and maintenance pruning

Remove any new symptom immediately

Final evaluation and establishment of annual preventive protocol

Document lessons learned and maintenance schedule

Step by Step

1
1. Identify all branches with canker symptoms during careful inspection
2
2. Sterilize pruning tools with 70% alcohol before starting
3
3. Cut infected branches 6-8 inches below visible canker area
4
4. Make clean angled cuts to facilitate water drainage
5
5. Sterilize tool between each cut
6
6. Apply bordeaux paste or copper fungicide to pruning wound
7
7. Dispose of infected material in sealed trash (do not compost)
8
8. Monitor plant weekly for new infections
9
9. Apply preventive fungicide to vulnerable areas
10
10. Improve cultural practices to reduce plant stress

🧪 Solutions

🌱 Natural Solutions

✓ Sanitation pruning removing infected branches 6-8 inches below visible lesion
✓ Destroy or dispose of infected material (do not compost)
✓ Apply bordeaux paste on pruning wounds
✓ Use neem oil as preventive during active growth periods
✓ Improve soil drainage and avoid overwatering
✓ Apply compost tea as plant immune system booster
✓ Spray baking soda solution (1 tablespoon per liter of water) biweekly

💉 Chemical Solutions

✓ Copper-based fungicides applied preventively during susceptible periods
✓ Bactericides containing streptomycin for bacterial cankers (where permitted)
✓ Systemic fungicides containing thiophanate-methyl or propiconazole
✓ Important: fungicides and bactericides have limited efficacy on established cankers

🛡️ Prevention

✓ Maintain plant vigor through proper planting, watering, and fertilization
✓ Select species and varieties adapted to local soil and climate conditions
✓ Avoid all unnecessary bark wounds
✓ Prune only when necessary and in dry conditions
✓ Sterilize pruning tools between each cut with 70% alcohol or bleach solution
✓ Apply mulch to maintain soil moisture and reduce stress
✓ Protect plants against winter damage and frost
✓ Remove dead or diseased branches promptly
✓ Avoid pruning when bark is wet to reduce spread
✓ Regularly inspect plants for early detection
✓ Minimize water stress through adequate irrigation during dry periods
✓ Apply balanced fertilizers to maintain overall plant health

🌿 Common in These Plants

African Milk Tree

Moon Orchid