Question
I have had numerous Jade plants in the house for many years now, recently a
mold has begun to attack the trucks of the plant causing it to fall over while the
top of the plant is still living.  Can you help?

Answer
This does not sound good.  If you see white mold growing on the stem of the plant, that is an indication of a fungal crown rot called Southern Blight or maybe some other fungal pathogen.  Not much can be done with this situation.  I would take as many babies off the plant as I could and re-pot them in clean potting soil.  The main plant stem will probably die.  There are some fungicide treatments that can be made to the soil, but at this stage it is probably too late.  Try to get as many survivors as possible to minimize your losses.  Daconil fungicide can be drenched around the base of the plant at a 1% solution.  This may help but I cannot guarantee success.  Good Luck.