Identifying and Treating Cochineal Scale on Prickly Pear Cactus

White Puffy Growth on Paddle Cactus? It's Likely Cochineal Scale

If your native prickly pear (Opuntia) develops white, cottony patches that spread and weaken the plant, you're dealing with a cochineal scale infestation—not a fungus. These tiny insects secrete a waxy white coating for protection, making them look like fungal growth.

What Is Cochineal Scale?

Cochineal insects (Dactylopius coccus) feed on cactus sap, causing yellowing, stunted growth, and eventual plant death if untreated. They're famously used to produce natural red dye (carmine), but in landscapes they're a destructive pest.

Effective Natural Control Methods

1. High-pressure water spray: Blast colonies off pads with a strong jet of water. Repeat weekly.
2. Insecticidal soap or neem oil: Apply thoroughly to all surfaces, especially undersides of pads. Reapply per label instructions.
3. Beneficial insects: Lady beetles and lacewings prey on crawlers (mobile nymphs).
4. Prune heavily infested pads: Remove and dispose of severely damaged pads (bag and trash—don't compost).

Persistence Is Key

Eradication takes multiple treatments because eggs are protected under the waxy coating. Monitor weekly and treat at first sign of recurrence. For detailed biology and control options, see Wikipedia's Cochineal article.