My number ONE control for the common succulent/cacti pest is rubbing alcohol.
I keep a bottle available, next to my plants, at all times.
A bottle of 70% solution, with a squeeze sprayer from any cleaning solution bottle screwed to it, creates a simple, effective tool.
Squirt, Squirt the bug is dead. Direct contact will kill most all sucking insects.
The most common ones being mealy bugs and scales.
Unfortunately it has no effect on adult scales which have "armored" themselves, but it does kill the juvenile "crawlers".
My second favorite pest control is Ultrafine Oil Spray.
It works by smothering the insects. Simple and effective and safe to use.
Bugs cannot develop resistance to it like they can to chemical insecticides.
It does work on the "armored" scales.
Safer's Soap is just as good and works by the same principle of smothering.
NOTE: Only use the oil or soap sprays when temperatures are cooler.
Published warnings on the oil say NOT to use above 80 degrees F. or in the hot direct sunlight of mid-day.
Always better to spray for pests and diseases in the morning or later in the day to prevent from phyotoxicity. (burning or curling of the leaves)
I use ultra fine oil on all my plants: orchids, citrus trees, hibiscus, plumerias, etc.
I DO Not spray oil on succulents with the white, waxy, powder coating. It dissolves the "farina" waxy, white coating, which happens to be a natural protectant.
