Q.grape plants in Tucson Arizona
Live in Tucson, 2 – 6′ grape plant, planted in Sept. Green leaves and some grapes until March. They are turning very brown on edges, grapes fell off and now leaves are brittle, brown and no new growth. What am I doing wrong? Fertilized in March and May. Thank you!

This could be due to a few issues.
The links below will help you determine the cause.
https://www.gardeningknowhow.com/edible/fruits/grapes/treating-grapevine-problems.htm
http://www.extension.umn.edu/garden/diagnose/plant/fruit/grape/leavesspots.html