What's eating my oncidium ornithorhynchum?

Oncidium ornithorhynchum is grown indoors and is most threatened by spider mites, which thrive in warm dry air around its fine foliage and pseudobulbs. Mealybugs and scale insects also attack, hiding in leaf axils. Inspect weekly and isolate any new plant for two weeks before adding it to your collection.

Fine webbing on leaves and pseudobulbs; stippled, silvery or bronze discoloration on foliage. Raise humidity, mist foliage regularly. Wipe leaves with a damp cloth; apply insecticidal soap or neem oil spray, repeating every 5–7 days until clear.

White cottony fluff in leaf axils and along pseudobulb grooves; sticky honeydew leads to sooty mold. Dab individual colonies with a cotton swab dipped in 70% isopropyl alcohol. For heavy infestations spray with insecticidal soap or diluted neem oil.

Brown or tan oval bumps on pseudobulbs and leaf undersides; weakened growth and yellowing leaves. Scrape off with a soft toothbrush, then treat with horticultural oil or neem oil; repeat after two weeks to catch crawlers.