Q.HOW TO CONTROL BLIGHT IN CONCORD GRAPES
WE LIVE IN NE OHIO, NEAR CANTON.
Certified GKH Gardening Expert
Unfortunately, it will be necessary to know which disease that your grapes have before you can proceed. There are many diseases, and they have different treatments. It will be important to know, exactly, what they have.
I would recommend taking samples to your local extension services. They will be able to test and identify the pest and offer treatment solutions.
Here are some articles that will help:
https://www.gardeningknowhow.com/edible/fruits/grapes/treating-grapevine-problems.htm
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm