What's eating my sempervivum calcareum?

Sempervivum calcareum is typically grown outdoors as a hardy alpine but also kept in pots indoors. Outdoors it faces vine weevil grubs eating roots, slugs targeting offsets, and aphids on flower stems. Indoors, mealybugs are the main threat. Root and crown rot from overwatering are more damaging than any pest.

Grubs eat roots; rosettes detach easily from the soil and collapse without warning Apply nematodes (Steinernema kraussei) to moist soil in late summer; use imidacloprid drench in containers

Irregular holes chewed in outer leaves; silvery slime trails around affected rosettes Hand-pick at night; use copper tape around container rims; apply wildlife-safe iron phosphate pellets

Clusters on flower stalks in spring; distorted stems and sticky honeydew Knock off with a jet of water; apply insecticidal soap spray; encourage ladybirds and lacewings

White cottony deposits in rosette centres on indoor specimens; stunted growth Dab with isopropyl alcohol; treat with neem oil; repot if root mealybugs are suspected