Urban Integrated Pest Management


Cochineal (Dactytopius confusus) belongs to a group of insects called scales. This group normally appears as flat, cryptically colored insects that do not move about on the host plant. They have a beak that penetrates the plant and allows feeding on the plant juices. Many scales exude a crusty material over the soft body that protects them. The cochineal secretes white waxy materials that protect them from most enemies and the environment. This white wax makes them resemble the mealybugs, a close relative of scales.

Cochineal is readily seen on prickly pear pads and cholla canes in urban scenes resembling a spit-wad war zone. The actual insect is seldom seen though, unless one teases away the wax to expose a quarter-inch long red bag, a female cochineal. This animal may remind one of the engorged dog tick. This red pigment, an anthraquinone, seems to protect the cochineal from most predators. This may also be the key to stopping parasites from attacking, as this insect is one of few with no known parasites affecting it. One predator that is not deterred is the caterpillar stage of a small moth, Laetilia coccidivora. This is a strange occurrence because few moth larvae are carnivorous. A small ladybird beetle is also a common predator found in the waxy home of the cochineal.

The cochineal disperses in a stage called the crawler. These juveniles hatched from eggs laid underneath the female, moved to a feeding spot and produced long wax filaments, then moved to the edge of the prickly pear pad where the wind catches the wax filaments and carries the cochineal to a new host. These individuals establish feeding sites on the new host and produce a dense wax covering surrounding the individual and others that have settled nearby. There are male and female cochineal insects, but the males are very tiny and have wings that allow them to fly about in search of mates on different cacti. Males are seldom observed.

Cochineal, which means scarlet-colored, is famous as a dye in both the textile and food industries. When Cortez landed in the New World in 1518 and proceeded to conquer the Aztecs led by King Montezuma, he discovered a highly developed textile industry with brilliant red garments. The Aztecs produced the red dye from an insect they called nochezli that fed on a cactus called nopal. The Spaniards eventually sent bags of dried cochineal back to Spain and the red dye use spread into many countries.

Michelangelo bought it to use in paintings, the British 'redcoats' and the Canadian Mounted Police coats were dyed with cochineal red. It is thought that the first U.S. flag made by Betsy Ross had cochineal red stripes. Other famous fabrics reported to have been dyed with cochineal include the breeches of the Hungarian Hussars, the Turks' Fez and the skull caps of the Greeks. Cochineal dye replaced another scarlet dye obtained from the insect called kermes, a scale insect that feeds on oak trees.

Modern use of the cochineal dye is limited, but has some followers in the craft world who weave and dye their own fabrics. There is also some use of cochineal as a food coloring. Because it is of insect origin some people might be squeamish about such use. Several other less-expensive aniline dyes have turned out to have deleterious effects in food so cochineal red dye may make a comeback. Before aniline dyes, cochineal was in such demand that the insect and the prickly pears that supported them were introduced into suitable climates throughout the world. Only a few of these areas, Oaxaca, Mexico, Algeria and the Canary Islands, were successful and now produce most of the dye used in commerce.

Extremely heavily infested pricklypear pads may die, but this plant is so prolific that removing damaged pads should take care of the problem. A strong stream of water aimed at the waxy cochineal should clean them up aesthetically.

Carl Olson
June, 2002

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