What's eating my euphorbia francoisii?

Euphorbia francoisii, a dwarf Madagascan succulent grown for its patterned foliage, is most vulnerable to mealybugs hiding in the tight leaf rosette. Root mealybugs can also colonise the soil undetected. Spider mites appear in very low humidity. Its latex provides some natural protection against chewing insects.

White waxy deposits in leaf bases and along stems; honeydew and sooty mould; stunted new growth Remove with alcohol-dipped cotton swabs; treat the whole plant with neem oil spray weekly for three to four weeks; isolate from other succulents

White powdery material on roots and potting mix surface; wilting despite adequate watering; slow unexplained decline Unpot, rinse all soil off roots, inspect and remove visible bugs, treat roots with a dilute systemic insecticide drench, repot in fresh sterile mix

Fine stippling or silvery speckling on leaf surfaces; very fine webbing in dry conditions Raise humidity; spray thoroughly with insecticidal soap or diluted neem oil, paying attention to leaf undersides; repeat every 7 days