Grape black rot

I have been trying to fight black rot in grapes, Guignardia bidwellii organically.
Quote from wikipedia, "Black rot is probably the “Achilles heel” for organic grape production in the East."
Cultural control practices didn't do much. Sanitized everything, even changes the ties. Organic approved sprays including copper seemed to provide very short term improvement (i.e. black rot started a little later). All mummies were cleaned up. The loss was 90% of grapes last year. The birds got the rest.

I don't know what varieties we have (there are 2) as the old owner planted them. He also sprayed, I am pretty sure. The grapes actually did great for 2 years after we inherited the vines (without spraying), but since then black rot has been here to stay.

Should I start over with new resistant varieties? Does anyone grow any actual resistant ones in area that is prone to fungal disease?

That sounds like it is caused by a fungus.  Have your tried a fungicide?

This thread has several simple recipes that would be cheap and easy to try:

https://permies.com/t/93537/toxic-Fungicide

I do not have any experience with that particular disease.

It may take several spraying to get it.

I merged your stuff with the following thread. I hope that is okay by you.

According to wikipedia, "black rot is probably the "Achilles heel" for organic grape production in the East". We had a rough couple of years with our (unknown variety) bunch grapes. Heavy losses to black rot. We are in WNC.

I have noticed black rot in the wild grapes around here also. Organic spraying is not enough. I did try bagging the clusters, but it turned out to be tricky. More pruning seems to help. Letting in the sun. Seems like I never do this enough.

The best harvest we had was when Japanese beetles obliterated the leaves. It let the light in! Also, I think the previous owner had sprayed them, and probably nonorganic stuff, and it kept the disease down early on. After a while, the black rot has gotten worse every year.  For now, continuing the cultural controls.

I don't want to dig up these huge older vines and start over.
The grapes we have right now have thick skins and seeds. Half are green and half are red.

Tanya White,
I have merged your topic into this topic. I hope that helps.

Did you look at this thread Tanya? There are a few suggestions on pruning and companion planting that might help.

The sun and airflow angle is real. I've noticed black rot is always worse on the shaded interior growth where things stay damp longer. Aggressive thinning of the canopy mid-season made more difference than any spray for me, just keeping the clusters exposed.

Nancy Reading wrote:I merged your stuff with the following thread. I hope that is okay by you.

I forgot I posted that!
Yeah, still having this issue.
My biggest hope is to hear someone's success story in a humid climate!

Joao Winckler wrote:The sun and airflow angle is real. I've noticed black rot is always worse on the shaded interior growth where things stay damp longer. Aggressive thinning of the canopy mid-season made more difference than any spray for me, just keeping the clusters exposed.

I am trying to prune more aggressively this year. Fingers crossed. Already lost some to black rot. Perhaps this is the most important cultural control?
I am not sure how anyone is able to grow grapes organically in a humid climate!