Brown spots/patches on Grape Leaves
The leaf spots could be anthracnose. Here is a link to a publication on diseases of grape including leaf spot diseases. I recommend you take a sample to your local Penn State extension office and have it identified there or at the plant clinic. Here is a link to their website. Penn State can diagnose and recommend a treatment plan. It's a good idea to remove and bag or burn the damaged leaves to help stop the spread of the spores to new areas.