African Milk Tree with Broad Mites? Rare but Treatable
Euphorbia trigona
Broad mites (Polyphagotarsonemus latus) are microscopic pests measuring only 0.25mm, making them nearly invisible to the naked eye. These arthropods feed on meristematic tissues at growing tips, injecting toxic saliva that severely damages new growth. They prefer warm, humid environments and reproduce rapidly, with females laying eggs every 2-3 days. The damage appears weeks after initial infestation, making early detection extremely difficult.
ð Symptoms
- âĒ Microscopic shiny amber or dark green mites (0.25mm) - nearly impossible to see without magnification
- âĒ New leaves appear puckered, shriveled, or have abnormal strap-like shape
- âĒ Leaf margins curl downward and become brittle or leathery
- âĒ Bronzing or dark brown discoloration at leaf edges
- âĒ Severely stunted or stopped growth at plant tips
- âĒ Distorted, twisted, or aborted flowers and buds
- âĒ Glossy or wet appearance on damaged new growth
- âĒ Plant appears healthy but new growth is severely deformed
â Possible Causes
- â Extremely small size (0.25mm) makes early detection nearly impossible
- â Toxic saliva injected during feeding causes distorted growth
- â Rapid reproduction - females lay 40-50 eggs in their lifetime
- â Thrive in warm (70-80°F) and humid conditions
- â Introduced through infested plant material, especially cuttings
- â Feed on meristematic tissues at growing points
- â Can be spread by workers, tools, and air currents in greenhouses
- â White flies may carry broad mites on their bodies
ð Treatment
Quick Fixes
Step 1
Isolate all affected plants immediately
Step 2
Remove and destroy all visibly damaged new growth and shoot tips
Step 3
Apply fast-acting miticide (abamectin or fenpyroximate) to entire plant
Step 4
Focus spray on new growth areas and undersides of young leaves
Step 5
Repeat miticide application every 5 days for 3 applications
Step 6
Lower humidity and increase air circulation around plants
Organic Treatment
Step 1
Immediately isolate infested plants to prevent spread to healthy plants
Step 2
Release predatory mites (Neoseiulus cucumeris: 50-100 per plant) on all plants
Step 3
Apply sulfur dust or sulfur spray to affected plants weekly
Step 4
Remove and destroy heavily infested shoot tips and new growth
Step 5
Apply neem oil (1-2% solution) every 7 days for 4 weeks
Step 6
Maintain humidity below 60% and ensure good air circulation
Step 7
Continue releasing predatory mites every 2 weeks for prevention
Step 8
Monitor new growth weekly with magnifying lens for 8 weeks
ðĄïļ Prevention
- â Quarantine all new plants for 2-3 weeks before introducing to collection
- â Inspect new growth regularly with 10x magnifying lens
- â Maintain good air circulation and avoid excess humidity above 60%
- â Keep temperatures below 80°F when possible
- â Remove and destroy heavily infested plant parts immediately
- â Isolate plants at first sign of distorted new growth
- â Avoid overcrowding plants to reduce mite spread
- â Sterilize pruning tools between plants
- â Control white fly populations that can spread mites
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.