What's eating my espostoa melanostele?

Espostoa melanostele, the Peruvian snowball cactus, shares the same vulnerability as related woolly cacti: mealybugs hide seamlessly in its dense white hair. Scale and spider mites are secondary threats. Inspect the cephalium and hair closely, particularly where the stem meets the soil, and act at the first sign of infestation.

White woolly pests blend in with the cactus's hair; look for yellowing or sunken patches beneath Spot-treat with alcohol swabs; drench soil with systemic insecticide; repeat monthly during growing season

Hard bumps detectable by touch along the stem beneath the white hair Carefully brush with alcohol-dipped stiff brush; apply neem oil to the stem surface

Sudden decline in a healthy-looking specimen; white cottony mass at roots on inspection Bare-root, rinse thoroughly, treat with imidacloprid solution; dry for 2 days before repotting