My Prickly Pear Cactus Pads Have White Patches That Peel Off

Identification

• A cochineal bug infestation is easy to identify on a prickly pear cactus. Take a knife blade and gently scrape off the white scaly patches. The patches peel off easily from the cactus surface. Gently crush the white material between your fingers. If it is a dark purple-red color, you have a cochineal bug infestation. The dye can stain gloves, cloth and fingers so wear old clothes when when handling cochineal bugs to avoid permanent stains.

Cochineal Insects

• The cochineal bugs are small soft-bodied scale insects that feed on cactus, particularly prickly pear species. Cochineal scale is identified under the scientific name Dactylopius coccus. The mature adults grow 1.5 mm long. As the insects feed, they create the white covering for protection. The soft-bodies insects produce a purple-red colored substance as a method to deter predatory insects. The insects are so tiny that when you scrape off and crush the white patches, they turn into a red-colored paste.

Control

• Mild infestations rarely damage the plants. Heavily infested cactus plants can develop yellow patches as the insects suck the sap from the plant. Remove the cochineal bugs with a strong stream of water. Wash off new patches as they appear. If your cactus is heavily infested, you can use a chemical control option such as an insecticidal soap or oil spray. Read the label before applying the insecticide. Handle chemicals carefully to avoid harm to the cactus or yourself.

Fun Fact

• The white patches look unsightly on your ornamental cactus and cochineal bugs are considered a pest, but these insects have value too. Native populations in the Americas, particularly in Mexico, used the cochineal insects to make dye for fabric. In the 1800s, dye made from the cochineal insects became an important export. The cochineal bug is still cultivated. Some personal care products, juice and candies contain the dye identified under the name carminic acid, according to the University of Arizona.