What's eating my rebutia krainziana?

Rebutia krainziana is a small, freely clustering cactus that is susceptible to mealybugs nestling between its many offsets and to root mealybugs below the soil. Spider mites can occur in dry winter rooms. Its habit of forming dense clumps creates perfect hiding places for sap-suckers, making regular inspection essential.

White cottony fluff between the densely packed offsets and at areoles; clump fails to flower and growth slows Divide the clump to expose all colonies; treat each offset with isopropyl alcohol swab; spray the whole clump with neem oil weekly for a month

Persistent decline and shrivelling despite regular watering; white waxy deposits on roots and inner pot wall Remove all soil, soak roots in imidacloprid solution, dry fully, repot in fresh, very free-draining cactus compost

Faint stippling and webbing on the small cactus bodies; usually worst in centrally heated rooms in winter Spray with insecticidal soap or neem oil every 5–7 days for three treatments; move to better-ventilated position