I was actually given some cochineal recently – unfortunately I haven’t got a prickly pear plant to infest with it, and as I haven’t messed with the plastic container the buggies are in…they’re probably dead by now.
If I want to get more, here’s places to try.
Maiwa
Aurora Silk
How many dead bugs do you have? Go ahead and dye with with them.
Cochineal is one of the few dyes I like to use filtered water for–it seems to latch onto any minerals in the water. I use an alum mordant (I usually pre-mordant my wool). Smash the bugs, simmer them in water for an hour or so, and filter them out. Simmer the wool (or silk) for an hour and let cool. If you want a true red, try adding a little acid towards the end. For more of a burgundy, add a little alkali (baking soda or ammonia)
Will they stay on just the prickly pear? I would wonder if they would infest other succulents as well or if they are primarily prickly pear pests.