I'm seeing the same thing on a neighbors grapes. Which is much worse. Either black rot or anthracnose. I'm fairly new at this though. From what iunderstand they would have to have been sprayed in the flowering stage. Those grape "mummies" (dried up ones) will fall to the ground and release spores for next year. If no spraying regiment through all stages of development, then at least remove all debris and litter from below the grapes, all dried up grapes must be removed.