another newbie grape growing question

[Huba Huba]

Couple of weeks ago I found a few leaves that looked like this and pretty much ignored them, they were on the trunk. Clipped them off and disposed them. Now they seem to be progressing upward and have found a couple on the cordons. Several vines are affected. Other leaves and the plant appear normal, nothing wilted and no lesions noted prior to parts of the leaf turning brown. It starts at the margins and progresses inward. vines are Norton/Cynthiana. Is this something to worry about? The nearest picture I can find on the internet looks like pierce’s disease, but I thought Norton was immune or at least resistant to that.
The leaf texture is soft and pliable, leather like, instead of “crispy”. img '62 is a bit atypical.
The last two, image's 64 & 65, are top and bottom of the same leaf.

 

[wood1954]

Have you reached out to any university extension office? My extension dept is quite helpful with these issues.

 

[Huba Huba]

I have but had to leave a message and have yet to hear back. Your post reminded me to try again.

 

[Huba Huba]

Extension agent said this is angular leaf scorch.
To me it doesn't look that much like pictures posted on the internet, but I am sure I know less than pretty much anybody. He recommended that I treat with anti fungal which can't hurt and something I probably should have done as soon as I suspected that I had a problem.
Are there any temperature restrictions on spraying Captan? Can't find any on the label but have read about problems when spraying antifuungals when temps are high. Last few days and the next couple will be mid to upper 90's. Plan on spraying tomorrow morning while temps are in the low 80's.

 

[wood1954]

thats a good plan, spray in early morning. good luck.