I think you have two kinds of bug - Spider Mite which gives you the silvery looking leaves also it looks like you have Armored Scale. Kelthane will help with the Spider Mites. Armored Scale which looks like black blisters is difficult. Acephate mixes are good - like orthene. It may take several applications to kill this stuff. It looks like the infestation is serious - and may kill you plants if not treated.