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Black rot treatment for grapes without spraying

 
Dan Cruickshank
Posts: 59
Location: Virginia
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All,

I have a great idea for keeping grapes without spraying, but I'm running up into problems with fungal diseases. (Chickens can handle most of the bugs.) Specifically, here on the East Coast and with all the water we get here, black rot is a common fungal disease of grapes. This year, black rot ruined all of the few clusters our young grape vines produced. (The non-rotted grapes were excellent, if a little small!)

A discussion with an old timer who remembers growing grapes in her youth tells me that vintners didn't always spray their grape vines and yet at one time they didn't have problems. Was this due to varietal selection? I don't know.

Looking on the internet, there's a reference to growing grapes in Mulberries and Elm trees and not having problems with black rot. Do Mulberries or Elm's give off some kind of antifungal, do their roots encourage the grape vines?

Another reference I have (can't find it right now) discusses how the three feet nearest the soil are prone to fungal attacks, suggesting that the lowest branches of fruit trees should be at least three feet off of the ground. Perhaps this was why the grape vines grown in trees, mentioned above, didn't have fungal problems? Perhaps other trees would work just as well? Or maybe just setting the first level of the trellis to be 5-6' high instead of 3'6" would work?

Does anyone have experience with growing grapes without spraying, that can offer some tips as to how to do it and still yield good grapes? I'm open to experimentation, but hoping someone else's experience might help focus my experiments.

Thanks!
 
tel jetson
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we grow grapes without any black rot or other fungal trouble, but we're in a rather different climate than you are. the vines are also around 90 years old, and we pretty much leave them alone apart from occasionally hacking off vines that are getting out of control. we probably aren't maximizing production, but that isn't really our goal, either.

they're growing on a sort of oversize arbor that I built a few years ago when the original trellis finally rotted apart. there are plenty of other plants growing under and around the vines, so splashing of fungal spores present in the dirt around them is probably fairly well suppressed.
 
Dan Cruickshank
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Location: Virginia
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Robert Hart suggests in his book on forest gardening that herbs help to cure fungal diseases. Martin Crawford agrees with this assessment, but notes that there is little scientific proof for growing herbs with fruit trees as a cure for fungal diseases. Crawford also notes, however, that having placed herbs underneath his forest garden he struggles with few fungal diseases.

Might raising an aromatic herb underneath grape vines help with black rot?

A quick search of herbs yields many with antifungal properties. However, given that I wish to run chickens in the vineyard during at least some parts of the year, that restricts somewhat which aromatic herbs I might be able to place there. Currently, I have heard that sage has mild antifungal properties, and that the chickens will tend to ignore it.
 
tel jetson
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we've got rosemary, oregano, thymes, and several mints growing under and around the grapes. chickens don't seem to bother very many of the aromatic herbs, so you would probably be alright planting them. I'm experimenting with planting aromatics to keep chickens out of garden beds.

even if it doesn't solve the fungus problem, herbs are handy to have around. tasty, medicinal, and insects like the flowers.
 
Dan Cruickshank
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Location: Virginia
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Tel,

This is very encouraging! Do you have any pictures you could offer of those herbs underneath the grape vines?

Thanks!
 
tel jetson
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Dan Cruickshank wrote:Tel,

This is very encouraging! Do you have any pictures you could offer of those herbs underneath the grape vines?

Thanks!


I sure don't. it all looks pretty wild at the moment, though. lots of nettles in there, which are great. there is also a lot of blackberry bramble and grass, which I'm not so thrilled about. as the good plants are spreading, and I continue to remove the blackberries and grass, things are getting better. there's some garlic and a few small olive trees in there, too. and some fava beans I failed to harvest that are sprouting. and some crosne. and some hops. mostly, though, it's a mess. a mess with some delicious grapes hiding in it sometimes.
 
Dan Cruickshank
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Location: Virginia
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Can you comment at all on whether the companion plants you have lower the yields of your grape vines? Most modern viticulture texts are very insistent that the "weeds" (i.e. companion plants) need to be kept to a minimum beneath grape vines.

Thanks!
 
tel jetson
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Dan Cruickshank wrote:Can you comment at all on whether the companion plants you have lower the yields of your grape vines? Most modern viticulture texts are very insistent that the "weeds" (i.e. companion plants) need to be kept to a minimum beneath grape vines.

Thanks!


hard to say for sure because we changed several things at once. apart from planting a whole bunch of things, I also pruned the vines hard so I could remove the old rotting trellis and began training them onto a much larger structure with a lot less pruning than was previously done. my guess, though, is that the other plants may well reduce the yield of grapes a bit, but they might also improve the quality and reduce the necessary inputs. and there are all the other yields to consider as well.

my experience generally is that polyculture usually reduces the yield of each element compared to a monoculture, while greatly increasing the total yield, quality (nutrition, vitality, taste, etc.), and reducing the labor and other inputs involved. I wouldn't expect the grapes and friends to be any different.

there are occasional exceptions to this, though. one example: adding mushrooms to a garden this year increased the vigor of the vegetables growing there while adding another crop in the same space.
 
George Sevkic
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I am no expert, all I can do is give you my experience.
Last year in Serbia was extremely hot and dry. Since grapes like it that way, my grapes although totally unattended, grew and yielded beautifully. I only needed to irrigate it occasionally.
In response to black rot, there are two ways my late father used: one is to raise your grapes higher than 1.5 meters to prevent evaporation from the soil to reach leafs. Spreading some rocks around the base of the grape is helpful also. sepp holzer talks about it too. Rocks, and concrete blocks ( or pieces of broken concrete) serve as suntraps, containing the heat and helping maintain favorable microclimate.
As for support plants, ordinary grass and for that matter any plants under the grapes that help prevent mildew and high humidity are helpful.
Once again, these are my observations. Hope it helps.
 
J D Horn
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Dan Cruickshank
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Location: Virginia
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Thanks for the comment on Lavender. I'd looked it up before, but can't seem to remember why I rejected it. I'll take a new look at it again.

Growing grapes 1.5 meters off the ground is an easy test to try. It will cost me a year to try it, but nothing more, so it's worth a try.

Lavender won't cost much either--I've got two lavender plants we started from seed growing in the window of my daughter's room. It's too cold to plant them today, besides--the chickens are doing some heavy soil work in the vineyard at this time anyway.

Looking up black rot at the library, I learned that it needs 2-3 days of wet weather in order to infect vines. (The article dates back to 1978--I'm not sure if any views of this have changed over time.) It also said that black rot was common East of the Rocky Mountains in the US. This leaves me wondering how relevant experiences are from the pacific northwest, or even Serbia, even though I welcome any and all thoughts in this matter. Here on the East Coast, black rot also infects ivy and virginia creeper. A history book I found recounts how black rot killed the budding commercial grape industry here in Virginia following the American civil war, until someone discovered a cure: antifungal sprays. I also note that this same commercial industry included acres upon acres of grapes grown in a monoculture.

Please keep the ideas coming. With your help, we might be able to solve this puzzle yet.


 
Chael Givan
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No personal experience with these, but they seem sensible, given that many come up in various forms as organic solutions to pest/disease management.

http://suite101.com/article/homemade-green-pest-control-for-gardens-a246065
 
Ken Peavey
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In '09 my tomato and potato crops were completely destroyed by Late Blight, P Infestans. While it is not a fungus, it displays some similar traits. In searching for a remedy (there is none, by the way), I tried some things which slowed down the destruction just a bit.

Surgery
Removing the infected part of the plant as soon as the problem is detected. Effects negligible due to the nature of the oomycete.
Removal of lower leaves and branches of plants in order to improve air circulation and promote a dryer environment. This slowed progress of the disease through sections of field.
Complete removal of the infected plant. It was already too late for the field in this instance.

Compost Tea
How long you brew it determines the dominant microbe. A day or so favors fungal populations. A couple of days promotes bacteria. 3 days or more promotes protozoa. The fungal dominant tea serves to place the beneficial microbes from the tea on the leaf, taking up the space which could otherwise be inhabited by the malevolent fungus.
Trying this in the case of P Infestans, I found the plants sprayed with the tea were among the last to go down. The spread of the infection through the plant was slowed, but it was unstoppable.


 
Sheryl Napier
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Dan Cruickshank wrote:Thanks for the comment on Lavender. I'd looked it up before, but can't seem to remember why I rejected it. I'll take a new look at it again.

Growing grapes 1.5 meters off the ground is an easy test to try. It will cost me a year to try it, but nothing more, so it's worth a try.



What exactly is meant by growing them 1.5 meters off the ground. Are the first leaves 1.5 off the ground or are they in a pot up on some sort of stand 1.5 off the ground?
My green grapes (who knows what variety) are totally being ruined this year. Do I prune the whole thing back, just let it run it's course or...?
I have 2 muscadines planted that are not having any black rot problem. Can they get it or will they be ok as they are adapted to the south. I live in the south east corner of Virginia.

Thanks, Sheryl
 
Dan Cruickshank
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Location: Virginia
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Sheryl Napier wrote:
What exactly is meant by growing them 1.5 meters off the ground. Are the first leaves 1.5 off the ground or are they in a pot up on some sort of stand 1.5 off the ground?
My green grapes (who knows what variety) are totally being ruined this year. Do I prune the whole thing back, just let it run it's course or...?
I have 2 muscadines planted that are not having any black rot problem. Can they get it or will they be ok as they are adapted to the south. I live in the south east corner of Virginia.

Thanks, Sheryl


Sheryl,

Here's what I mean: Normally, they tell you to put the bottom wire of the trellis about three feet off of the ground. Suppose you instead put that bottom wire up higher, say four to five feet? In all other respects, the grape is grown the same: they are planted eight feet apart, in rows that are eight feet apart, planted in the ground, etc.

Dan
 
Dan Cruickshank
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Location: Virginia
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Here's a fascinating observation: I visited an individual in the DC area who kept a large grape vine. His grape vine grew along the edge of his property on a fence. At one point, the vine grew underneath the roof of the woodshed, and then kept going on the other side. When I asked, he confirmed that none of the grapes that grew under the roof of the open woodshed had black rot on them, whereas the rest of the vine struggled with black rot.

Does that mean you could build a "roof" over your grape vines to keep them from getting wet in the rain, and that if you did so you wouldn't have any problems with black rot?

Just a thought,

Dan
 
Jonathan 'yukkuri' Kame
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Location: Foothills north of L.A., zone 9ish mediterranean
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We are very dry here in SoCal and this year was dryer and normal, but 3 out of 5 grape vines around the house have bad powdery mildew.

The 2 that don't have it are seeded green muscats of some sort. The muscats are by far our favorites - so fragrant and flavorful!

The diseased ones are 'modern' seedless grapes. One is red flame, the other some kind of red table grape. Sweet, but otherwise unremarkable.

Chalk another up for Mother Nature knows best.
 
Dan Cruickshank
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Location: Virginia
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+1 for varietal differences. Our Seedless Reliance grape vine set a wonderfully huge crop, and it was destroyed by black rot this year. (We've had some wet weather, at exactly the wrong time.) However, a Mars grape vine that I planted last year has several clusters turning color with no sign of black rot at all. Is this because the Mars vine is growing in a welded wire fence? Because that was the fence protecting the garden? Because the chickens were on the other side of that fence? The Cawtawba vine growing in a chain-link fence looks to have some black rot on it. It's growing right next to beans in one garden, but has no chickens near it. Is that because Mars is less susceptible to black rot than Cawtawba, Cayuga, or Reliance?

I don't know, but I'm still looking for the answer. I'll keep you posted.

Thanks for all those who have shared ideas!

Dan
 
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