What's eating my bolivian torch cactus?

Bolivian Torch Cactus (Trichocereus bridgesii) is a fast-growing columnar cactus most troubled by mealybugs in its areoles and scale insects along the ribs. Spider mites attack in hot, dry rooms. Its large size can let populations build unnoticed at the back of the stem, so inspect all sides monthly.

White cottony patches in areoles, especially toward the growing tip; honeydew dripping down ribs; stunted new growth Swab each spot with isopropyl alcohol; spray the full stem with diluted neem oil; repeat every two weeks until no signs remain

Hard brown or tan discs fixed to ribs; yellow halos around attachment points; gradual decline in vigour Scrape off manually with a soft toothbrush; apply horticultural oil spray covering all rib surfaces; treat twice, two weeks apart

Fine dusty webbing, especially on sun-facing sides; pale stippling across the epidermis in dry conditions Rinse with water, treat with insecticidal soap spray; ensure adequate ventilation and avoid positioning next to radiators