Good Morning Jessica, 

Thank you for contacting the U of M Extension Service. 

Please click on this link from the U of M Extension Yard and Garden website about growing grapes in MN: https://extension.umn.edu/fruit/growing-grapes-home-garden#diseases-and-other-challenges-986261

If you scroll down to Diseases the article discusses good air circulation to prevent various mildew diseases. From your photos, it appears your vine is against a wooden fence which would hinder good air circulation. With the mildew diseases, the leaves become distorted, stunted and can curl and fall off. 

The article also states: 

 Equally important is raking and removing leaves each fall as well as picking up and composting fallen fruit. After pruning, remove cuttings away from the vines. These practices will remove some of the places disease can overwinter to infect the following spring.

Good Luck!