Common Houseleek with Spider Mites? Rare but Treatable
Sempervivum tectorum
Spider mites are tiny arachnids (less than 1/20 inch long) related to spiders and ticks that feed on plant sap. They thrive in hot, dry conditions and can cause significant damage to ornamental and vegetable plants. During severe infestations, crop losses can reach 14% or higher as these pests disrupt vital plant processes including photosynthesis, carbon dioxide absorption, and transpiration.
ð Symptoms
- âĒ Pale discoloration spots on leaves
- âĒ Fine silk webbing covering leaves and stems
- âĒ Tiny yellow or white speckles on leaf surface (stippling)
- âĒ Leaves taking on yellow or bronzed appearance
- âĒ Flecking and scorching of foliage
- âĒ Reduced chlorophyll content
- âĒ Premature leaf drop and potential plant death
â Possible Causes
- â Hot and dry weather conditions
- â Low humidity environments
- â Water-stressed plants
- â Dusty conditions on foliage
- â Overuse of pesticides killing natural predators
- â Poor air circulation around plants
- â Bringing infested plants indoors or near healthy plants
ð Treatment
Quick Fixes
Step 1
Immediately spray all affected plants with rubbing alcohol (70% isopropyl) diluted 1:1 with water
Step 2
Apply insecticidal soap or horticultural oil directly to visible mites
Step 3
Wipe leaves with damp cloth to physically remove mites and webbing
Step 4
Spray undersides of all leaves thoroughly with water mist
Step 5
Repeat alcohol or soap treatment every 3 days for 2 weeks
Organic Treatment
Step 1
Isolate infected plants immediately to prevent spread
Step 2
Spray undersides of leaves with strong water stream daily to dislodge mites
Step 3
Apply neem oil solution (mix with Coco-Wet) every 3-5 days, covering all plant parts
Step 4
Use insecticidal soap spray at 3-day intervals until control is achieved
Step 5
Apply diatomaceous earth to soil surface and lower leaves
Step 6
Introduce beneficial predatory mites (Phytoseiulus persimilis) for ongoing control
Step 7
Monitor plant daily and repeat treatments as needed
ðĄïļ Prevention
- â Maintain adequate irrigation and soil moisture levels
- â Inspect plants weekly for early signs of webbing or stippling
- â Wash trees and vines with water mid-season to remove dust
- â Install drip irrigation systems for consistent moisture
- â Track hot and dry weather and increase watering during high-risk periods
- â Provide shading during extreme heat
- â Encourage natural predators like lady beetles, predatory mites, and minute pirate bugs
- â Quarantine new plants before introducing them to your collection
- â Maintain optimal growing conditions through proper fertilization and temperature control
ðą Care Guide: Common Houseleek
ð§ How to Water
Water sparingly, allowing soil to dry completely between waterings. In summer, water once every 2-3 weeks. Reduce to monthly or less in winter. Overwatering is the main killer - when in doubt, do not water.
âïļ Lighting
Requires full sun for best coloration and compact growth. At least 6 hours of direct sunlight daily. Can tolerate partial shade but may become leggy and lose vibrant colors. Provide afternoon shade in extremely hot climates.
ðŠī Ideal Soil
Requires excellent drainage - use sandy, gravelly, or gritty soil. A cactus/succulent mix works well. Tolerates poor, rocky soils. Never use moisture-retentive potting mixes.