Sometimes a prickly pear or a Christmas cholla growing in the shade of a mesquite tree is covered with what seem to be tiny balls of cotton. Closer examination reveals the "cotton" is composed of silky threads with tiny flecks of red. When one of the white puffs is removed and placed under a microscope, the red specks prove to be cone-shaped, waxy and composed of disc-like segments. No head or legs will be visible. The "cotton" is cochineal.
Cochineal is a crimson dye, which is obtained from the bodies of insects. The insects belong to the family dactylopiidae, a group of scale insects. Scale insects are serious pests of cultivated plants, particularly fruit trees, shrubs and greenhouse plants. But the dactylopiidae, or cochineal insects, live only on cactus.
When the Spaniards conquered Mexico they found the Aztecs producing cochineal, and the Spaniards continued the industry. In 1802 more than three million pounds of cochineal were exported from Mexico. The Spaniards moved the insect to other colonies, and by 1876 world production amounted to seven million pounds a year.
The Spanish monopoly on cochineal lasted centuries, leading to political intrigue, murder, espionage, bribery and more, as other countries sought to find the source of the carmine dye valued by the wealthy and the religious. As other counties learned how it was produced, the English introduced prickly pear cactus to India, South Africa and Australia. Even though prickly pears became an invasive pest and covered a million acres in Australia, the cochineal insect did not adapt to that environment and no cochineal was ever produced in Australia.
Amy Greenfield's "A Perfect Red" is a superb book about the history of cochineal production. The discovery of aniline dyes in the latter 1800s brought about the decline of the industry. Cochineal carmine still is used today, mostly in hair and skin care products, but also to color pills in pharmaceuticals. Sometimes it is listed in food products -- from meat, to preserves, to cheese and juices -- again as a coloring agent.
There are seven species of cochineal insects, and each feeds on several species of opuntia, prickly pears and related cacti. The cochineal of commerce is not found in Texas. The cochineal, which most often attacks Christmas cholla, is dactylopius newsteadi and is probably the most common species locally, but there has not been a recent methodical study of the cochineal in West Texas.
Research has revealed the life history of Cochineal insects. The eggs are laid singly and hatch in 15 minutes to six hours into six-legged active pink or red larvae, termed crawlers. Newly hatched male and female crawlers are indistinguishable, but differ in their development.
Female crawlers select a permanent position and commence to feed by inserting the proboscis deep in the plant tissue and remain stationary for the rest of their life. They begin to secrete a woolly protective covering as soon as they settle down. Once the proboscis has been inserted in the plant, the insect cannot be removed without breaking that delicate organ and killing the insect. The legs shrink and become functionless. Within 40 to 90 days the female begins laying eggs.
The male crawler moves about freely and inserts and withdraws his proboscis frequently. Finally he crawls onto a female culture and spins an oval white silky cocoon. In about 15 days, the male emerges as an active fly with two delicate white wings. But it no longer can feed. Its function is to fertilize the female and die. The females continue to reproduce for three to six weeks. Crawlers are produced in all except the coldest months of the year.
Cochineal feed on all the above ground portions of cactus plants, but in general prefer young growth. When the infestation is heavy, the infested joints shrivel up and fall off. Mann states cochineal colonies grow more rapidly when protected from direct sunlight. Heavy rains wash the crawlers and even well-grown cultures from the plants. Rain also destroys the protective woolly covering of the females and exposes them to predation. Thus, dry weather aids the increase of cochineal. During the crawler state, the insects are carried easily by wind currents, which explains their arrival even in the oldest parts of town.
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