Noble Dendrobium with Spider Mites: Prevention & Cure
Dendrobium nobile
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: Noble Dendrobium
ð§ How to Water
Water thoroughly once a week during the growing season (spring-summer), allowing the mix to almost dry between waterings. Reduce watering significantly in fall and winter, just enough to prevent canes from shriveling. Resume normal watering when flower buds appear.
âïļ Lighting
Provide bright indirect light, ideally near an east-facing window or shaded south-facing window. Avoid direct midday sun which can burn the leaves. Good light is essential for flowering.
ðŠī Ideal Soil
Use a well-draining orchid bark mix. The plant is epiphytic in nature and requires excellent drainage. Repot every 2-3 years when the medium breaks down or roots outgrow the pot.