Help Identifying Small Brown Spots on Grapes

[JackH]

Hi all,
Hoping to get a little help identifying small brown spots on my grapes.
Background:
20 vine backyard vineyard in southeast Pennsylvania,
Second year for the vines which are all Vidal Blanc sourced from Double A vineyards
Have had vigorous growth both seasons and have kept a few clusters on each vine this year to 1) confirm species, and 2) allow for pilot scale abatement attempts for spotted lanternfly.

I have been following a spray schedule I set up with the help of Double A, that includes Copper, Sulfur, Fruit Tree Spray, Immunox and Captan.

I started noticing the spots about 2 weeks ago. Photo collage attached showing the spots. I cant seem to match it to any of the photo-guides to grape diseases. Would love to know what it is and how to mitigate it. Thanks in advance.

 

[srcorndog]

Contact your land grant college I think it is Penn State send them a sample and contact your count extension agent

 

[JackH]

Contact your land grant college I think it is Penn State send them a sample and contact your count extension agent

Thanks, will do.

 

[ibglowin]

Possible issue:

https://grapes.extension.org/phomopsis-cane-and-leaf-spot-and-fruit-rot-of-grapes/

 

[JustJoe]

I found very similar spots on my grapes and another member here suggested it could be anthracnose. I didn't think it looked like it but the next day I found the easily recognizable round spots with the dark margin and brown center. I have now sprayed with captan and hoping for the best.

 

[JackH]

Thanks for the input. I've made contact with my county extension and hope to hear back soon.
Cheers!

 

[Papa Giorgio]

Dealing with what seems to be the same. Attached picture below. Does Antoine know how to remedy? Copper fungicide? Literally googled grape disease cures and copper fungicide popped up. I’ve no idea if I should be using it or not. Pic attached below

 

[JackH]

Dealing with what seems to be the same. Attached picture below. Does Antoine know how to remedy? Copper fungicide? Literally googled grape disease cures and copper fungicide popped up. I’ve no idea if I should be using it or not. Pic attached below

I just submitted samples to my state ag extension (Penn State). Will report their findings.

 

[JackH]

Just received this from my state extension disease clinic (Penn State): "No pathogens were found on the grapes. The small brown spots on the fruit are the lenticels. Some grape cultivars have darker lenticels and this is just a normal characteristic of the fruit"

Happy to get this news to say the least! Older and wiser.

 

[Cynewulf]

Dealing with what seems to be the same. Attached picture below. Does Antoine know how to remedy? Copper fungicide? Literally googled grape disease cures and copper fungicide popped up. I’ve no idea if I should be using it or not. Pic attached below

That is black rot. You can remove the infected berries and should be spraying with something effective against black rot (copper is not) earlier in the season like mancozeb or immunox, paying attention to the pre harvest interval (PHI) of the fungicide. The berries themselves will develop ontogenic resistance against disease 4-6 weeks after bloom. You start to see black rot now, so, what should you do?

 

[VinesnBines]

Just received this from my state extension disease clinic (Penn State): "No pathogens were found on the grapes. The small brown spots on the fruit are the lenticels. Some grape cultivars have darker lenticels and this is just a normal characteristic of the fruit"

Happy to get this news to say the least! Older and wiser.

I started to suggest it was just lenticles. Vidal seems to be a variety that has darker lenticles.

Dealing with what seems to be the same. Attached picture below. Does Antoine know how to remedy? Copper fungicide? Literally googled grape disease cures and copper fungicide popped up. I’ve no idea if I should be using it or not. Pic attached below

On the other hand you can actually see the difference in lenticles and rot in Papa Giorgio's picture. Rather than black rot it may be botrytis bunch rot. In any event Immunox and Captan together won't hurt and may help whichever it may be.