What's eating my crassula columnaris?

Crassula columnaris is an unusual, column-forming Cape succulent whose tightly imbricated leaves shelter mealybugs effectively. Root mealybugs are a hidden but serious risk. Scale insects occasionally attach to stems. Because the plant is small and slow-growing, any unchecked pest can cause disproportionate damage — inspect at every watering.

White cottony masses wedged between the tightly overlapping leaves or at the stem base; column looks dull and fails to elongate normally Use a fine brush or cotton bud dipped in isopropyl alcohol to work between leaf layers; systemic neem drench for root-zone infestations; isolate the plant immediately

Plant wilts despite appropriate watering; white powder on roots confirmed only at repotting Unpot carefully, rinse roots, treat with dilute imidacloprid or neem soak, repot into fresh gritty compost; delay next watering by 10–14 days

Brown or grey flat oval bumps adhering to the column stem; gradual weakening and yellowing of upper leaves Manually remove with a toothpick or soft brush; apply horticultural oil spray; repeat after two weeks to catch hatching crawlers