My Dad planted a variety of wine grapes a few years back. The fruit is usually picked clean by the birds. But the vines are doing great and I had fun photographing them for you.
Black Rot on Grapes
Some of the grapes fall victim to a fungal disease called Black Rot. It causes small yellow spots on the leaves that turn into brown spots. The young grapes will shrivel and turn black, making them look like little grape mummies.
You used to be able to purchase copper sulfate for treating the developing grapes. Alas, that same preparation was used to kill all of the algae in ponds by folks who wanted crystal clear water. The unfortunate result was the death of most everything else in those ponds. The suggested treatment now is a chemical called Captan…definitely not an organic option.
Copper sulfate was considered a viable organic treatment way back in the day. Perhaps it is best that this concoction isn’t available to the general public. But I wonder about all of the chemicals that are still available, like Captan. What effect does it have on bodies of water and their inhabitants?
I’ve read that baking soda helps treat powdery mildew. I wonder if it would be helpful in controlling Black Rot? Have you had any experience with organic controls for this dreaded grape disease?
I suppose it couldn’t hurt anything to try the baking soda treatment, along with cleaning up old fruit that falls to the ground, and trimming vines to keep good air circulation around the fruit so that they don’t remain wet…one of the conditions the fungus loves so much.
Have you had experience with Black Rot on grapes? What treatment worked for you?