What's eating my wheel cactus?

Wheel Cactus (Opuntia robusta) is a large, blue-green prickly pear grown as a houseplant, patio plant, or garden specimen. Cochineal scale is the most serious and characteristic pest of Opuntia species, conspicuous as white tufts with crimson interiors. Mealybugs and spider mites are secondary indoor pests. Outdoors, deer and rabbits occasionally browse pads despite heavy spination.

White cottony patches across pad surfaces; crushed insects produce bright red pigment; severe infestations cause pad yellowing, wrinkling, and drop. Knock off with a strong water jet; scrub affected areas with neem oil or insecticidal soap and a soft brush; repeat every 10–14 days; improve air circulation.

White fluffy deposits in spine areoles and along pad margins; honeydew secretion; slow growth. Apply isopropyl alcohol with a cotton swab or brush; follow with neem oil spray; repeat weekly until absent.

Fine webbing and pale speckled patches on pad faces; most common in dry indoor or greenhouse conditions. Wipe pads with a moist cloth; spray with neem oil or miticide; move away from dry heat sources and ventilate.

Pads chewed at ground level or broken off; most common in winter when alternative food is scarce. Install wire mesh or fencing around plants in gardens with deer or rabbit pressure; raised planters help for rabbits.