
What kind of pest is this and what can I do?
I recently visited my mother's place and noticed her Euphorbia Trigona is infested with these white spots. I thought they were mealy bugs but they are hard and sort of incrusted on the surface. I tried 70% alcohol spot treatment and the reaction was nothing like with mealy bugs. They come off kind like a crust would. Any ideas of what it is and how it could be treated?