What's eating my thorny chin cactus?

Thorny Chin Cactus (Gymnocalycium horridispinum) is a slow-growing globe cactus most affected by root mealybugs and mealybugs in the areoles and rib grooves. Spider mites occasionally appear in hot, dry rooms. Its low-growing, ribbed form keeps pests close to the soil line — check the rib bases and soil surface closely.

Cottony white clusters in rib grooves and areoles; sticky residue at the base; distorted or yellowed new growth Remove with isopropyl alcohol on a cotton swab; spray the plant and rib grooves with diluted neem oil; repeat every 10–14 days

Shrivelling body and poor growth despite correct care; white powdery filaments on roots when repotted Unpot and clean roots; allow to dry; replant in fresh well-draining mix with a neem oil drench; repeat monthly

Pale dusty mottling or webbing on rib surfaces in dry, warm indoor conditions Rinse the plant with water; apply insecticidal soap spray; increase air movement around the plant