What's eating my orchid?

Phalaenopsis orchids are most commonly attacked by mealybugs and scale insects, both of which hide in leaf grooves and along roots. Spider mites strike when air is too dry, and thrips damage flowers and buds. Inspect under leaves and between pseudobulbs monthly — scale insects in particular are easy to overlook until damage is severe.

Hard or soft brown bumps on leaves, stems, and roots; yellowing and pitting of leaf tissue; sticky honeydew leading to sooty mould. Scrape off with a soft toothbrush; wipe leaves with a cloth dampened with 70% isopropyl alcohol; apply neem oil spray fortnightly for 2 months.

White cottony masses at leaf bases, in root crowns, and between leaves; leaves yellow; plant growth stalls. Remove with alcohol-soaked cotton swabs; drench roots with insecticidal soap solution if root mealybugs suspected; isolate from other orchids.

Silver streaks and scarring on petals; distorted buds that fail to open; tiny dark frass specs on flowers. Remove affected flowers; apply spinosad or insecticidal soap spray to foliage; use blue sticky traps to monitor populations.

Tiny pale spots and stippling on leaves; fine webbing on leaf undersides; leaves become silvery or bronze and may drop. Increase humidity around the plant; rinse foliage with lukewarm water; treat with neem oil or insecticidal soap spray weekly until resolved.