Pest identification
What's eating my blue dendrobium?
Mealybugs
Signs: White cottony masses at cane joints and under sheaths; canes shrivel and growth stalls
Control: Dab colonies with 70% isopropyl alcohol; apply diluted neem oil spray every 10 days for four cycles
Scale insects
Signs: Hard brown bumps on pseudobulbs; honeydew accumulation and sooty mould on lower canes
Control: Scrape off manually with a soft toothbrush; treat with methylated spirits then neem oil monthly
Fungus gnats
Signs: Adults emerge from bark mix; larvae chew young roots and root tips, stunting new growths
Control: Allow the top of the bark mix to dry slightly between waterings; use Bti drench and yellow sticky traps
Keep blue dendrobium pest-free
Healthy plants resist pests best. Get the basics right:
Blue Dendrobium pests — FAQ
What is eating my blue dendrobium?
Blue Dendrobium (Dendrobium victoriae-reginae) is a cool-growing orchid most threatened by mealybugs and scale insects at pseudobulb nodes and in leaf sheaths. Fungus gnats can breed in bark-based potting mix that stays damp too long. Root rot from overwatering is far more common than pest damage in this cool-preference species.
How do I get rid of mealybugs on blue dendrobium?
White cottony masses at cane joints and under sheaths; canes shrivel and growth stalls Dab colonies with 70% isopropyl alcohol; apply diluted neem oil spray every 10 days for four cycles
How do I get rid of scale insects on blue dendrobium?
Hard brown bumps on pseudobulbs; honeydew accumulation and sooty mould on lower canes Scrape off manually with a soft toothbrush; treat with methylated spirits then neem oil monthly
How do I get rid of fungus gnats on blue dendrobium?
Adults emerge from bark mix; larvae chew young roots and root tips, stunting new growths Allow the top of the bark mix to dry slightly between waterings; use Bti drench and yellow sticky traps