First time on the forums here, so please forgive me if I have posted in the wrong location. Two years ago, I planted a small Japanese maple sapling in a small back yard here in Connecticut. Recently, I have noticed that about 50% of the leaves on the plant have been damaged (see picture attached). I am brand new to the gardening world, so I am uncertain if this damage is caused by bugs or by some type of disease. Any help identifying the problem, along with any suggestions on what to do, would be very appreciated.