Question
All of my pothos plants have brown wart-like bumps on the stems.  Are they bugs and can they spread to other plants?  What should I do with the pothos plants?  Also, what causes it?

Thank you for your time!

Answer
Dear Elaine, Your pothos has scale, a common insect infestation of house plants.  They do spread easily so you will want to control them.  Scale is an insect which doesn't move in its adult form and lives under a hard protective coating or scale which protects them from most ordinary insecticides.  The best control is to spray the entire plant with horticultural oil (not kitchen oil, it is not the same thing).  This will suffocate the scale and cause it to drop off.  You will know it is dead when the dried scales fall off with no effort or a moderate stream of water aimed at them.  You may have to spray several times about a week apart to get effective control, but this method WILL work.  Interesting that you should ask what causes this.  I always found it amazing that insect infestations are able to occur in high rise office buildings away from other plants.  Somehow the insects find a way in - as airborne larvae, or traveling inside by other methods, ad they manage to flourish in the absence of any predators.  After you spray a few times, you should fix the problem.  Good luck, Melissa