Help, something is blistering my orchid cactus leaves. Picture is
posted on alt.binaries.pictures.gardens. I've got two or three varieties of
something Wife calls "orchid cactus" growing in the greenhouse. One (the
most beautiful when it decides to bloom) has this blight that I can't seem
to slow down. I don't want it to spread into the others until I learn
something about control.
Each little spot seems to start with a little watery blister, and then
dry up into a much harder brown blister. I thought at first it was some kind
of a bug inside the early stage blister. I popped one or two open and using
a 10x glass looked for something squirming or with legs...... nothing I
could identify.
Is this ailment something anyone knows about? And also I'm sure that
there is a better name for the plant than "orchid cactus"..... maybe some
help there too!

Thanks in advance!
Lynn (really rank amateur greenhouser)