What's eating my lithops?

Lithops (living stones) are extremely drought-adapted and rarely troubled by pests. Root mealybugs are the most serious threat, attacking roots in the soil. Fungus gnats can damage fine roots if watering is too frequent. Overwatering causes more deaths than any pest, so the best defence is restraint with water.

Waxy white deposits on roots and lower stem; plant shrivels or fails to plump up after the correct watering season. Unpot carefully, inspect roots, remove all soil, treat with systemic drench (imidacloprid), and repot in completely dry, gritty mineral mix.

Larvae feed on the thin, hair-like roots; plant stalls or rots at the base; adults hover around the pot. Keep soil dry for extended periods as per Lithops watering schedule; use Bti soil drench; add a layer of coarse grit on the surface to deter egg-laying.

White fluffy masses where leaves meet; sticky residue on the 'body' surface; slow rot can follow. Apply 70% isopropyl alcohol with a fine brush or cotton swab directly on colonies; avoid getting excess moisture into the central fissure.