What's eating my sulcorebutia rauschii?

Sulcorebutia rauschii is a tiny, flat-bodied cactus with very short spines, making it particularly vulnerable to mealybugs and root mealybugs — there is little physical barrier to stop sap-suckers. Spider mites can mark the dark purple or green skin. Its small size means infestations overwhelm the plant quickly if not caught early.

White cottony deposits at the sparse areoles and between clustering heads; the tiny plant declines rapidly under even moderate attack Use a fine brush dipped in 70% isopropyl alcohol on each colony; spray whole plant with dilute neem oil; repeat every 7 days; quarantine immediately

Unexplained shrinkage and shrivelling of the body; white waxy insects found on roots at repotting Bare-root, wash roots, soak in imidacloprid drench for 15–20 minutes, air-dry for 3–5 days, repot in sterile mineral cactus mix

Pale stippling or bronzing on the distinctive purple-brown skin, sometimes with barely visible webbing; worst in hot dry rooms Spray with insecticidal soap; improve air circulation; avoid placing directly above or near heating sources