What's eating my euphorbia obesa subsp. symmetrica?

Euphorbia obesa subsp. symmetrica (baseball plant) is a compact, nearly spineless succulent that can attract mealybugs sheltering at the ribs, and spider mites in overly dry indoor conditions. Root mealybugs are a hidden threat below soil level. The toxic latex deters many insects, making serious infestations uncommon.

White woolly deposits between the ribs or at the base; sticky honeydew; plant growth slows and the globose body may shrivel Dab visible colonies with isopropyl alcohol; spray neem oil solution over all surfaces; repeat weekly; check the base carefully

Unexplained wilting and yellowing despite adequate water; white powdery colonies visible on roots when plant is unpotted Unpot and inspect roots; rinse roots clean; soak in diluted neem or imidacloprid solution; repot in fresh dry compost

Very fine stippling on the plant body; dull or slightly webbed surface in dry indoor environments Raise humidity around the plant; wipe the body gently with a damp cloth; apply insecticidal soap or neem oil spray; repeat every 5-7 days