What's eating my euphorbia symmetrica?

Euphorbia symmetrica, a compact globose South African Euphorbia kept as a houseplant, faces its greatest threat from mealybugs wedged in the prominent rib grooves. Root mealybugs and scale insects also occur. Its caustic latex discourages most chewing pests but offers no protection against piercing or sucking insects.

Cottony white wax in rib channels and near the growing point; reduced vigour and honeydew residue. Apply alcohol with a cotton swab to exposed colonies; follow with neem oil or pyrethrin spray; treat every two weeks.

Small brown or tan waxy bumps adhered to the ribs; yellowing and weakened plant if left unchecked. Scrape off scales with a soft toothbrush, apply insecticidal soap or neem oil, and repeat fortnightly.

Gradual wilting and soft body despite correct watering intervals; white wax coating on roots at inspection. Unpot, rinse roots, drench with systemic insecticide solution, let dry, then repot in fresh well-draining mix.