Question
I live in Sydney, Australia and my two pittosporum trees have borer. I have painted rogor around the trunk over a 3 month period but the borer persist. Why is this happening and what can I do to control this pest?

Answer
Shirley:
Suggest sending your question to an entomologist, a person who has a great deal more knowledge of insects than I.  It is my understanding however,that most insecticides for borers work best as preventatives-that is, they need to be on the plant before the critter arrives there. Bores are often hard to get to once they are in the wood.

Hope this helps.
Steve