It finally happened. The cochineal bug has invaded my garden and attached itself to my lone Engelmann’s Prickly Pear (Opuntia Engelmannii.) Other than an occasional watering in the depths of summer, I normally don’t pay much attention to this cactus, so it was only by chance that I caught this invasion early and began to treat it.
The cochineal scale insect resides in small fluffy white webs on cactus pads, which is what it feeds on. Some cacti can become covered with cochineal scale, which will eventually kill the cactus if it is not treated. Cochineal is partial to Purple Prickly Pear (Opuntia Santa Rita) but so far, my two are unaffected. Birds spread the insect from cactus to cactus with their feet, so maybe it's just a matter of time.
The way to determine if the white fluffy stuff on a cactus pad is cochineal is to squeeze the web. If it’s cochineal, it will ooze a scarlet red color, as shown in the photo. To eliminate it, I spray the cactus with a power spray of water to rid it of the webs. This may not rid the cactus completely, but by keeping down the population, it will help keep the cactus healthy.
For centuries, the dried and crushed bodies of cochineal scale insects have been as a non-toxic fabric dye. This natural dye is becoming popular again among weavers, to the point that harvesting of the cochineal is a commercial enterprise in Mexico as well as other parts of the world. Thornless Prickly Pears are now available in these commercial enterprises for easier harvesting.
I’ve been experimenting with the stuff as a dye for gourd crafting, but I think it takes another ingredient to assure its permanency. I think I’ll stick to leather dyes and alcohol inks and leave the chemistry to others.