What's eating my huernia zebrina?

Huernia zebrina (lifesaver cactus) is an indoor stapeliad most seriously threatened by mealybugs, which suck sap from stems and roots and can kill the plant if unchecked. Spider mites attack in dry heated air. Scale insects occasionally colonise the angular stems. Good light, lean compost, and regular inspection are the key defences.

White cottony masses on stems or at the soil line; root mealybugs cause wilting and stunted growth with white deposits visible when unpotting. Remove with 70% isopropyl alcohol on a swab or spray. For root infestations, unpot, rinse roots, air-dry 1–2 days, and repot into fresh compost. Apply a systemic insecticide if needed.

Fine silk webbing in the angles between stem teeth, and tiny pale speckles on stem surfaces — most common in low-humidity winter conditions. Spray thoroughly with diluted neem oil or insecticidal soap. Repeat every 5–7 days for three weeks. Improve air circulation around the plant.

Small hard brown or tan bumps on stems, causing yellowing and weakened growth; easy to overlook on angular four-angled stems. Scrape off individual scales with an isopropyl-alcohol-dipped cotton swab or soft brush. Follow with a neem oil spray to catch juvenile crawlers.