Spider Mites on anthurium
What's Happening
Spider mites and thrips target Anthuriums due to their thin, velvety leaf texture which provides easy feeding access. Thrips (Thysanoptera) rasp leaf tissue and suck sap, causing silver stippling that appears as scattered yellow/brown spots with black frass (excrement) visible under magnification. Spider mites (Tetranychidae) colonize undersides, spinning fine webbing and causing stippled yellowing from cell destruction. Both pests exploit low-humidity environments (<60% RH) and spread rapidly in indoor conditions with poor air circulation.
How to Fix It
- 1
Confirm diagnosis: Use 10x magnification on leaf undersides—thrips = slender insects + black frass; mites = tiny dots + fine webbing; both cause similar stippling
- 2
Isolate immediately: Move affected plant away from others to prevent spread
- 3
Mechanical removal: Shower leaves with lukewarm water to dislodge pests; wipe undersides with damp cloth daily for 1 week
- 4
Apply treatment: Use neem oil (1 tsp per quart water + surfactant) or insecticidal soap; spray to runoff covering all leaf surfaces
- 5
Repeat treatment: Apply every 5-7 days for 3-4 weeks to catch life cycle stages; rotate between neem and soap to prevent resistance
- 6
Increase humidity: Boost to 70-80% RH during treatment—high humidity inhibits mite reproduction and supports plant recovery
How to Prevent It
Quarantine new plants for 14 days; inspect weekly with 10x loupe, focusing on leaf undersides and new growth; maintain 60-80% humidity (mites thrive in dry air); improve air circulation with gentle fan; apply preventive neem oil spray monthly; isolate any plant showing early stippling immediately.