Question
I planted a Don Juan climbing rose.  The leaves have
little holes all over them.  What causes this and
what can I do to provent it?

Answer
The little holes are the result of what is called a shot holed fungal infection. Usually this happens if you get a wet or dull spring. Any spray for rose fungus infections such as black spot, will solve the problem. It is not caused by insects. I should say if you can't see the insects than it is a fungal problem.