What's eating my crassula undulata?

Crassula 'Undulata' (a jade plant cultivar) is most commonly troubled by mealybugs, which colonise its ruffled leaves and tight stem joints. Spider mites can appear in dry heated rooms in winter. Fungus gnats are a risk if watering is excessive. Overall it is a robust plant with few pest issues when grown correctly.

Waxy white deposits nestled between ruffled leaves and in stem crevices; sticky honeydew; reduced growth. Spot-treat with isopropyl alcohol on a cotton bud; follow with weekly neem oil spray; isolate the plant.

Fine pale flecking on leaf surfaces; faint webbing under leaves; leaves dull and eventually drop if neglected. Rinse foliage; boost humidity slightly; apply insecticidal soap every 5–7 days for 3–4 treatments.

Larvae in waterlogged compost chew roots; persistent adult gnat swarms; yellowing and wilting follow root damage. Let compost dry well between waterings; apply Bti soil drench; top-dress with coarse grit to deter egg-laying.