First I tried smothering, and now I’ve become a poisoner.
I’ve become very protective of the cacti out front, which this year seem to have been hit hard by something called cochineal scale. The tiny insects spin a white cottony, waxy fluff that protects against the elements, then literally dig into the plant and eat away, dessicating the pads.
Remember awhile back when Starbucks had to redo some of its drinks because it turned out that the red coloring was coming from bugs? Cochineal were those bugs — they’ve been harvested for years to make the scarlet dye known carmine, because when you crush them they leave a bright red pigment. I’ve just downloaded a book called A Perfect Red that’s about how the Spaniards transported cochineal from Mexico to Europe, where they had a monopoly for centuries on what created the most intense red available.
Anyway, the cochineal is ruining my damn cactus. I first tried to go the ecological route with neem oil, which we used to keep bugs from eating our grapevines. The oil seems to work in a couple of ways: (1) it coats the bugs and suffocates them; (2) insects who live but come in contact with the oil seem to “forget” how to eat, and starve rather than chomp down on the plant.
But a week later, still lots of scale. I want to be able to make prickly pear syrup again this year — and the plant is beginning to look rather shameful, with dessicated sections — so today I broke down and bought two bottles of Sevin insecticide and sprayed the plants. I knew it would kill other, perhaps beneficial insects, too, like ants, so I took caution in directing the spray. (I got the handheld bottles rather than the kind you hook to a hose.)
Here’s hoping it does the job, because the alternative is to heavily prune the affected areas, then scrub the remaining plant with brushes to remove all signs of the scale. And that is, sadly, about the level of commitment where I would say: “Hey, homeowner — this is now your problem to deal with.”