Hi fruit experts, one of my grape varieties looks sick, I have no idea what this can be. Fungus? Nutrient Deficiency? The berries seem fine inside. When I rub them, some of it comes off, but not all. The leaves seem OK. Any ideas how to deal with this? Thanks!
Looks like botrytis cinerea, the grey mold. You need to spray fungicide and possibly cut all affected clusters.
You should also make sure to thin out any side branches on your vines. It is also advised to remove leaves around grape clusters to improve ventilation and allowing any moisture to dry as fast as possible.
It is very common in hot and humid weather.
What variety is it by the way?
Ventilation needs to happen as soon as the blossoms set berries, removing all leaves that prevent direct sunlight into the fruit is imperative especially if you are in a wet climate. Probably too late for fungicide to help. Mark you calendar for next spring to ventilate the fruit much earlier!
Dennis
Kent, wa
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Thanks. We’ve had a lot of rain and heat this season, so that explains it.
Will do, Dennis. I am very new to growing grapes so still learning. What fungicide would you normally use? I’ve been using copper fungicide on some of my other fruit and berries, or is there a better product?
The variety is Somerset.
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You may want to improve ventilation on the other varieties even though they are not affected, yet. Things may change later on. Also check your grapes regularly for continuous growth and really very often in humid weather. Some diseases like perenospora affect leaves, mainly where those lack airflow and if untreated may result in defoliation.
Depending on your zone and climate you may consider different styles of training. Some are intended for better ventilation.
That being said, sometimes grape growing can be a lottery. You may do your best and things turn out however the weather allows…
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Actually Mark I do not ever have a problem such as this with my grapes, so none is needed here. What region are you located?
BTW welcome to the forum
Dennis
I’ve got the same problem, and am also growing Somerset. Been growing it for about 4 years, it’s an super vigorous vine but seems extremely susceptible to grey mold. I’ve had problems with it for the last 2 years but this year it has been very wet, and sadly it looks like I might lose the entire crop. I’ve got Concord growing right beside it that is completely unaffected. In the early years of my gardening journey I put them both on opposite sides of a small trellis which I naively thought would be enough room for both. Fast forward to today and I’ve got an impenetrable mess of tangled grapes vines with no airflow. One of them has got to go and it’ll probably be Somerset given that Concord is just more disease resistant.
Thank you, Tana. I went ahead and pruned all the leaves that were shading the clusters, and removed all the clusters that were affected, leaving only healthy ones and those that had no more than 10-15% discolored berries. I also removed most of the bad berries from those clusters and sprayed all my vines with copper fungicide. I hope that helps get some harvest from Somerset. Thanks for your advice.
I’ve never had this problem in the 3 years that I’ve been growing grapes, this is the first time I see it. I am in the Niagara Falls region.
Mike, I have two Somerset vines, one Himrod, and one Sovereign Coronation. Both Somerset vines are affected, nothing on Himrod and SC. I’ve also noticed that one of the Somerset vines is much more impacted and that’s the one that was shaded more. Lesson learned, I will make sure to give them more sun and more airflow by better pruning.
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I’m also growing Himrod, but it hasn’t fruited yet, so glad to hear it’s unaffected. How does it taste? Between mold, Japanese beetles, lack of adequate space I find my interest in grapes starting to wane. I’m not really a big fan of either Somerset or Concord. Despite being classified as ‘seedless’ Somerset still has tiny, soft seeds even when it’s fully ripe. Concorde tastes amazing but the tough skin and rubbery texture aren’t great for fresh eating. I’m looking for a good table grape and hopefully Himrod is that.
I’m impressed by the size of your grapes, Mine are about 3-4 weeks later maturing,
Today I pruned my second time since first last week. The pics below give you a good idea of how much light I get down to the fruit. It’s also the time to make certain two things are happening:
Each bunch of grapes has direct sunlight and
Each bunch is hanging freely so they are much easier to remove when ripe
I prune every two weeks removing every sucker that emerges.
Dennis
Kent wa
Before I could not see most bunches
What are the dimensions of your trellis? This will help me with a trellis plan I’m in the midst of.
Thanks
Get rid of it. That variety is not good for your area, I highly recommend Blueberry Seedless Grapevine Blueberry grape variety: a profile - Greg Alder's Yard Posts: Southern California food gardening I purchased a bare root vine like 3 years ago, not spraying, have it in a pot under a loquat tree, it managed to climb, now I get like 10 paint buckets of grapes every year. Before I tried all kinds of varieties and they would get fungi or aphids, ants viruses, my carlos muscadine is doing great too.