The Cotton Patch

What Is That Stuff?
Don't be alarmed if you see white cottony patches on your santa rita cactus! ( Opuntia violacea var. santa rita ) We often find clumps of the wooly-cottony substance on our plants. We find it more often in humid warm weather, but, today noticed a healthy- looking cluster on one of our cactus, even in the cooler weather...yesterday low, 35 degrees, here.

The cactus is native of Texas, Arizona and Northern Mexico but grows very easily here, in Borrego. A mature plant is an outstanding addition to a desert garden. Our garden contains several specimens.

Before you worry too much about what causes the patches, let me assure you, they are very easy to control! Just hose them off with water from the strongest setting your nozzle has...and keep washing until they are gone. Sometimes , you will see a whitish puddle of water containing the "cotton". If you haven't removed all and notice others, wait a few weeks and repeat the process.

The Beetles!
The Cochineal beetle sticks her nose into the cactus pad to get nourishment. She secretes the white cottony substance to hide and to prevent drying out. She stays in one place but the male has wings and can fly to females for fertilization purposes...after which, he dies. The female is wingless, but her cotton patch will grow into colonies following fertilization and spread about the leaf and plant.
Lots of Uses...
This little beetle produces carminic acid, which can be extracted from her body and eggs to make carmine dye, now used as a food coloring (E120 on the food label) and in rouges, lipsticks, jams. preserves, sauces, meats, poultry and many other places, such as the stain for slides in microbiology.
Historic Beetles!
The Aztec and Maya people long used the dye for fabrics and valued its vivid red- purple color. When the Spanish entered the picture, they saw the value in the product and took it back to Europe and kept it as a State secret. Called the "royal" color, it was available to only the rich. They controlled the market and it wasn't until late 1700 that the rest of the world was let in on the secret!
See for Yourself!
I took a metal pick and scraped off a gob of cotton. With a lens, I looked into the sticky mess and noticed the body of the beetle. I squeezed it and saw the bright red drops of a blood-like substance. It got on my fingers, along with some glochids, and dyed my thumb purple - is it indelible? I'll let you know !