This sounds like it could be a disease called 'Shot hole disease\" which is caused by a fungus. You really need a definitive answer before treating so I suggest you bring a leaf sample inside a plastic bag to your local Master Gardening clinic or nursery. They should be able to tell you if a fungal infection is causing the holes. Damp, humid weather encourages this fungus among us. Sometimes a spray can help but again, you must have an in-person diagnosis to make sure you are dealing with a disease rather than an insect. Keep growing, Marianne Binetti