What's eating my argyroderma testiculare?

Argyroderma testiculare, a living-stone succulent from the Western Cape grown as a houseplant, is mainly threatened by mealybugs hiding at the base between the paired leaves and by root mealybugs attacking the shallow root system. Fungus gnats can damage roots in overly moist conditions. Its compact, low-lying form deters most other pests.

White waxy powder or fluffy tufts lodged at the cleft between paired leaves and around the base. Apply 70% isopropyl alcohol with a fine swab directly to each colony; avoid wetting the leaf surfaces; repeat weekly.

Plant fails to plump up after watering; white powdery material found on the fibrous roots when unpotted. Unpot, shake off all soil, rinse roots, soak briefly in insecticidal soap solution, air dry, and repot in sterile gritty mix.

Larvae chew fine feeder roots in wet soil; adults are nuisance fliers that indicate excess moisture. Allow soil to dry out fully between waterings; use sticky yellow traps for adults; drench soil with Bacillus thuringiensis israelensis (Bti).