I thought some people might be interested. I had an old CO2 tank with a
regulator and needle valve left over from my aquarium days. I put a
couple of potted phals in a large kitchen trash bag and used a twist-tie
to seal the neck of the bag around the 1/2" hose from the tank. I
regulated the flow to be just enough to keep the bag inflated. After 4
hours I removed the plants. The visible scale insects seemed to be quite
dead, which I judged by the fact that they were no longer firmly
attached to the leaf.

Have I finally found a way to win this battle? I sure hope so.


--
Peter Aitken