Question
HI David,
I have recently discovered a disease that has spread to my succulents.  I
rescued an unknown succulent that was doing fine until a noticed white flat
flaky spots about 1-2mm in diameter that can be scraped off.  it is turning
the leaves a brownish and wilted/withered.  This has spread to another
succulent that was adjacent.  my suspicion is some sort of fungus.
is there anything i can do to treat and/or prevent it from spreading to my
other plants?
thanks.

Answer
You are describing scale insects, which can suck the leaves dry and cause them to wither.  I would treat the plant with an insecticide.  I would treat the plant with Bayer Advanced Tree and Shrub Insecticide.  This product is mixed with water and poured on the soil around the base of the plant.  It is taken up systemically and will kill the bugs within a week or so.  It also provides protection from reinfestation for up to a year.  This should fix the problem.  Good Luck.