What's eating my euphorbia stellata?

Euphorbia stellata, a geophytic succulent with a large caudex and slender stems, is susceptible to mealybugs sheltering at the caudex neck and stem bases. Root mealybugs are a risk if soil stays too moist. Spider mites appear occasionally in dry conditions. The caudex is the most vulnerable part to inspect.

White powdery wax at the caudex neck and where slender stems emerge; gradual yellowing of stems. Apply 70% isopropyl alcohol directly to colonies; treat with systemic neem oil drench around the caudex base.

Unexplained wilting or stunted growth; white waxy coating visible on roots when plant is lifted from the pot. Bare-root the plant, rinse with water, treat roots with diluted neem, let dry, and repot in fresh mineral mix.

Fine webbing and pale stippling on the thin, pencil-like stems; more common in low-humidity environments. Increase humidity near the plant and apply insecticidal soap spray; repeat every 7 days for three weeks.