Marquette grape disease or burn

[wood1954]

So yesterday my grapes were very healthy, this afternoon it got up to 95 and either black rot or chemical burns from my mancozeb, sulfur, phostrolf fungicide spray 3 days ago wreaked havoc, half my plants are damaged. Anyone with experience with Marquette grapes or any grapes see this and have any advice

 

[Skashoon]

Sort of looks like leaf scorch. Marquette does have a slight sensitivity to sulfur.

 

[wood1954]

Kinda what I was thinking but I looked at several leaves with a lens and didn’t see any evidence of spores or fruiting bodies, but might just spray with Immunox tomorrow to be safe.

 

[wood1954]

Skashoon, I think you are right, there is no sign of fungus or mildew. No more sulfur for my vines.