Question
I have an avocado tree inside the house that is about 20 years old. It is about 6 feet tall.  I moved to a new house 2 years ago and since have had problems with what I believe to be brown soft scale insects. there is sticky residue every where and small brown spots on leaves.  What can I do to get rid of them and not harm the tree?

Answer
You can do one of several things.  Bayer Advanced Tree and Shrub Insecticide is a systemic product that is mixed with water and poured on the soil around the base of the tree.  It will kill the bugs within a couple of weeks.  I do not know if it is labeled for avacados.  If the tree does no make fruit, dont worry about that.  The other method is a little more laborious.  You can take a Q-tip and some heavy mineral oil and coat each bug.  The mineral oil will suffocate them.  This may be too much trouble if there are many scale on the tree, but it does work.  Do not cover too much tree surface, especially leaves, or you may suffocate the tree as well.  Good Luck.