Question
I have a hibiscus tree/plant that I keep indoors.  There are brown/black bumps spreading all over the bark of the tree.  They easily come off by plucking them and they have hard shells.  The are very small about the size of 1/2 an pencil eraser.  They are not on the leaves.  I have treated it with soapy water and two treatments of insect killing soap for houseplants.  What are these pests and how can I get rid of them?

Answer
Lisa,

They are an insect called scale so you are on the right track. In fact you may have already killed them but they will not come off until you physically rub them off. You can do that with your fingers, a cotton ball dippped in rubbing alcohol or a paper towel. You might want to tae it ourdoors to rub them off or put a sheet of plastic under it. Or just vacuum well afterwards. You can also treat them with either rubbing alcohol or Neem oil availble at many garden centers ( I know Lowes) in a spray bottle. Neem Oil is a natural organic insecticide/fungicide that is safe to use indoors around children, pets and yourself. Scale seems to be getting to be a lot worse problem in the last few years. Watche your plants closely in the future now that you now what it looks like and spray with alcohol or Neem oil at first sight. It doesn't have to be black. The little bumbs can be cream colored or green or clear or brown. If you see similar little bumps on the stems or the bacs of leaves spray thoroughly twice a week for 3 weeks so you kill any eggs that hatch. Good luck.

Darlene