Garden and Orchard

Grape Vines and Black Rot

ripening grapes
A healthy bunch of grapes!

Dad’s Vineyard

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?

34 Comments on “Grape Vines and Black Rot

  1. My neighbor has grape vines which suffer badly from black rot. This year i grew tomatos on his property which i spray with a heaping table sppon of baking soda two tablespoons of vegetable oil and a few drops of Dawn in a gallon of water. every time i sprayed tomatos this year I sprayed the grape vines. I sprayed after every rain to keep blight down in the tomatos. What I noticed was this year we had an abundance of grapes and very little grape black rot. There had been no usable grape harvest in years. I went over this week and picked a five gallon bucket of grapes and could probably get another. It seems to help with the black rot by the amount of grapes produced.

    1. Hi Jim,
      Thanks so much for sharing your recipe for an anti-fungal spray that is inexpensive and easy to mix up. This looks great and I’m going to try it! Thanks! Lisa

  2. I have a couple of vines of green grapes that have developed black rot. Is it okay to eat/press the grapes that do not show any signs of rot?

    1. Hi Kevin,
      I would throw away and grapes that are touching the infected grapes and then wash the rest of the good grapes well before using them. I hope this helps… Lisa

  3. I work at a winery we have about 4 acres of plants. We use a combination of sprays for mold rot etc. Captan mixed with Manzate are the two we spray about every ten day or so. Or if we get a inch of rain we spray right after. I know you can buy a version of Captan on Amazon don’t believe you can get manzate. We also use abound which you need a license to get same with manzate. At the start of each year you use a sulfate before plants start to bud and once again in the fall when all the leaves have fallen off. Not sure this will help because most you need a license for. Keep plants pruned of to much leaf and vine is a must for air to move through also.

    1. I’m trying to avoid the use of non-organic sprays on my grapes at home but this might help some folks who don’t have the same requirement. Thanks for sharing.

  4. Grapes and vines always beautiful but, for years, no grapes due to black rot. Read that New Zealand uses 40/60 milk to water solution after grapes finish blooming. I made a gallon with diluted powdered milk, (according to box directions,) and added 1 tablespoon baking soda. Spray leaves and grapes two times a season, (more if much rain/humidity) pick off the few grapes that might show signs of rot, keep vines trimmed a bit if things get too shady. This has worked well for me for four years. Milk does not have to be powdered.

  5. I recently moved into a house that has a grape vine in the backyard. I ate one of the grapes before realizing that almost every grape on the vine has what looks like Black Rot. Is it safe to eat grapes with Black Rot?

    1. Hi Carmen,
      It shouldn’t make you sick to eat one but I think it would be best not to eat anymore.

  6. They say to “Make a typical baking soda spray by dissolving 1 teaspoon of baking soda into one quart of water. You can add a few drops of insecticidal soap or liquid soap to help the solution spread and stick to the leaves. Only use liquid soap, like Ivory, and not laundry detergent. Stir this mixture around and then pour it into a clean, empty spray bottle.”

    I didn’t get a chance to do this, this year To my grapes but def trying next year. They say it will work on black spot and powdery mildew on grapes. I know it works on powdery mildew as I used it to treat my squash plants this year.

  7. I just eat the grapes and drink the grapes wine but, i never think about the grapes diseases. My uncle has a greenhouse and i will consult with him.

  8. We have a small boutique organic vineyard in Texas. We strugglle hard with black rot every year. We are trying commercial grade hydrogen peroxide this year so we are hopeful that we wont kose every single grape. Unfortubateky it isnt eradicated vecause qe are still picking off mummies, so our onky hope is to somewhat control it. Would love to know if/when anyone has success with baking soda

    1. Hi Julie,
      I’m sorry to hear that you are having so many issues with your grapes. My vines have all died and I don’t think my Dad is growing them anymore. If I hear anything, I’ll let you know. If you try it, please come back and let us know how it worked.

    2. Looks like it can work. I used 3 tablespoons/liter of water and some dish detergent for the first application; too concentrated. Looks like the fungus damage stopped but I also burned lots of leafs. I will try again since the recommendation is to spray again after 7-10 days. However, in the meantime I received the sulfur powder and I will spray with 2 tablespoons sulfur/gallon of water this week. My grand parents used one or two tablespoons of sulfur (90 or 95%)for every 10 liters (2.64 Gal) of water but they also mixed it with the Bordeaux mixture to kill two birds with one spray. They were also spraying every 2 weeks I believe and their grapes were just gorgeous.

  9. Some of my concord grapes had black rot. Is it safe to eat the luscious healthy looking grapes that have ripened?

      1. Hi Bret,
        Sorry I didn’t see this sooner. I don’t know if the flavor of the wine will be compromised. I think you would want to taste the good ones to see if the flavor of the grapes are different and go from there.

  10. Hi Lisa. We planted grape vines several years ago and were so happy last year when they were full of clusters of grapes. And then they got the black rot and we lost all of them. :'( We pruned the vines way back and did everything we read about trying to prevent it, but we had it again this year. We are so disappointed and really don’t know what else to do. I’ll be following and watching to see if anyone has some advice to share. Great post. Thanks for sharing. ~Katie

    1. Hi Katie,
      Cleaning up the old grapes and leaves is the first line of defense. Also allow for good air circulation to help prevent the proper conditions for the fungus to grow. My Dad wants to try using the acidified copper sulfate that I bought for treating my chickens for large roundworms. It will likely be a year before I know if that works. He can’t buy copper sulfate in New York anymore, but you might be able to in your area. I hope you find a good solution and share it with us too!

    1. Hi Bill,
      My grape vines are still young and haven’t started to bear yet. It usually takes 3 years after planting. The ones in the photos are my Dad’s vines.

      Check to see if you vines get full sun, have some room to grow, and are getting enough water and nutrients. When you prune, be sure to leave at least 2 to 4 lateral branches from the year before. Here is a good guide on pruning…https://grapegrowingguide.com/grape-pruning.html

      Also, make sure you aren’t piling on too much nitrogen, which will encourage green growth at the expense of flowers and fruit.

      Hope this helps!

  11. in the past we ignored it. just like tomatoes it is usually there because of the moisture that year and next year will be better or at least different. it has never affected all our fruit either.

    1. Hi Marcie and Chris,
      I think that is what my Dad has been doing, but he has had no fruit survive to eat the last couple of years. He hates to use ‘chemicals’ but he also wants some grapes 🙂 Thanks for stopping by! Sorry I missed the tomato tasting this weekend…sounds like you had a great time!

  12. I heard you could use a solution of Hydrogen Peroxide and water. Not sure the ratio, but it helps on tomato plants. It can’t hurt to try the baking soda as well. Good luck.

  13. We are grapevine newbies and do not have any actual grapes yet. I don’t have any advice, but do love your photos. There is something so gorgeous about grapes, grapevines, and vineyards.

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