What's eating my echinocereus pectinatus?

Echinocereus pectinatus (rainbow hedgehog cactus) is an outdoor desert cactus most threatened by cochineal scale, which coats stems in white waxy fluff and drains sap. Rodents and rabbits may gnaw the base in winter. Spider mites can attack during hot, dry spells. Dense spination deters most large browsers.

White cottony or powdery wax on stem surface; beneath it, clusters of pink-red insects drain sap, causing yellowing and shrivelling Blast off with a firm jet of water, then scrub with a soft brush dipped in 70% isopropyl alcohol; repeat weekly; neem oil spray as follow-up

Fine silvery stippling or russeting on the stem surface, sometimes with faint webbing at spine bases, most visible in hot dry summers Rinse with water to reduce dust; apply insecticidal soap or neem oil spray; improve air circulation and avoid drought stress

Gnawed or chewed stem base, especially in winter when other food is scarce; can sever young offsets Surround plants with a low wire mesh guard (hardware cloth); place fine gravel mulch at the base to discourage burrowing