African Milk Tree with Bacterial Wilt? Rare but Treatable
Euphorbia trigona
Bacterial wilt is a fatal vascular disease caused by bacteria (Erwinia tracheiphila, Ralstonia solanacearum, Xanthomonas spp.) that infects the water-conducting tissue of plants. The bacteria multiply and block the flow of water and nutrients, causing rapid wilting and plant death within 1-2 weeks.
ð Symptoms
- âĒ Wilting of individual leaves on a single stem, appearing suddenly
- âĒ Plants wilt during the day but may recover overnight in early stages
- âĒ Youngest leaves show wilted appearance while still green
- âĒ Leaves turn yellow and brown at margins progressively
- âĒ Complete withering and death of foliage
- âĒ Brown discoloration visible in vascular tissue when stem is cut
- âĒ Milky-colored sap with sticky consistency oozes from cut stems
â Possible Causes
- â Bacterial infection by Erwinia tracheiphila, Ralstonia solanacearum, or Xanthomonas species
- â Transmission through insect vectors (cucumber beetles, aphids)
- â Entry through feeding wounds, roots, or damaged plant tissue
- â Spread via contaminated tools, hands, or infected plant debris
- â Warm, humid conditions favor bacterial multiplication
- â Use of infected seeds or transplants
ð Treatment
Quick Fixes
Urgent isolation
Immediately isolate infected plant from other plants to prevent contamination.
Complete removal
Remove entire plant including all root system. Use gloves and clean tools.
Safe disposal
Place all material in plastic bag, seal tightly and dispose in regular trash - never compost.
Site disinfection
Remove surrounding soil (30cm radius) and disinfect pot/area with diluted bleach.
Monitoring
Observe nearby plants daily for wilting signs over the next 2 weeks.
Organic Treatment
Immediate removal
Immediately remove all infected plants including roots. Do not compost - dispose in sealed plastic bag.
Tool disinfection
Disinfect all tools with 70% alcohol or bleach solution (1:9) before and after use.
Soil solarization
Cover affected soil with clear plastic for 4-6 weeks during summer to eliminate bacteria through heat.
Biocontrol application
Apply Trichoderma or Bacillus subtilis to soil to compete with pathogenic bacteria.
Soil improvement
Add quality organic compost and ensure good drainage to strengthen beneficial microbiota.
Crop rotation
Do not plant susceptible species in the same location for at least 3-4 years.
ðĄïļ Prevention
- â Control insect vectors (cucumber beetles) using row covers or organic sprays
- â Practice crop rotation: avoid planting susceptible plants in same area for 3 years
- â Use certified pathogen-free seeds and transplants from reputable sources
- â Choose resistant varieties labeled as "Bacterial Wilt Resistant"
- â Maintain good garden hygiene: sanitize tools between plants
- â Remove and destroy infected plants immediately (do not compost)
- â Apply copper-based bactericides preventatively before symptoms appear
- â Exclude beetles with floating row covers during seedling stage
ðą Care Guide: African Milk Tree
ð§ How to Water
Water only when soil is completely dry, typically every 3-4 weeks. Reduce watering in winter. Wrinkled leaves indicate thirst. Yellowing or browning may signal overwatering and root rot.
âïļ Lighting
Prefers bright indirect light to direct sunlight. Can tolerate some direct morning or afternoon sun. Avoid harsh midday sun which may cause scorching. Also adapts to medium light conditions.
ðŠī Ideal Soil
Use well-draining sandy or cactus mix. A 2:1:1 blend of cactus soil, perlite, and coarse sand works well. Good drainage is essential to prevent root rot.