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Reviving "sick" vines

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WillNic

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Hi guys,

I'm super new to winemaking, so apologies in advance for any topical faux pas!

My parents recently bought a small lifestyle plot with a pre-established small pinot noir vineyard. The grapes look to me like they've been neglected for some time, and much or the leaves appear to have some form of mildew. Also suspect the vines haven't been watered for quite some time.

I noticed that, as harvest approached, a large proportion of the grapes were getting holes in them and essentially drying up or going moldy. The holes don't look like they're from birds (we also covered with nets), so I'm wondering whether its some form of blight attacking? Have attached photos to hopefully indicate their ailment a bit more clearly. It also wasn't an over-ripeness thing, because they weren't sufficiently sweet and the seeds were still mostly green.

My question is: what is this affliction (are the mildew and the holey grapes connected?), and is there a way to treat it without dousing the whole vineyard in sprays? I'd like this to continue as an organic, spray-free vineyard if possible.

And on the same note, has anyone experimented with cover crops in small scale vineyards? Any recommendations? The climate here is cold and with relatively little rainfall (Cromwell, New Zealand).

Thanks in advance,
Will

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Johny99

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Looks like it could be powdery mildew or just water stress. The grapes don't seem to have any. The grapes may simply be lack of water. I don't know how wet you are, but if you are in an area where it is common to irrigate that is a possibility. If there are holes, it could be insects. We have that problem with yellow jackets, and other wasps will also bore into the grapes. Generally that is localized and you see them.

Do you have a farm extension resource with the government or a university down there? Our local one is a great resource. Another resource would be any local growers. I'm guessing they'll be really busy right now, but might be approachable a month or so after harvest. If you are lucky you might find a small one that would welcome a volunteer for picking. That is how I've gotten my hands on education.

And PS welcome to the forum!
 

grapeman

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You have a bad case of powdery mildew on the grapes- leaves and fruit. On the grapes it often causes them to split open and rot. If some have small holes that could be from hornets, wasps or yellow jackets feeding on them. It will be hard to control the powdery mildew with strictly organic spray regimen but if you begin control early and it remains relatively dry for the growing season you might get by. I think it has gotten too far on you for this year though.
 

WillNic

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Thanks Johny and Grapeman for your responses, much appreciated. I'm inclined to agree that the problem is a powdery mildew one, but it makes sense that it might have been exacerbated by a lack of water during the growing season. There's irrigation installed, and during late summer I'd say the vines do need to be watered, so that could be contributing.

I've harvested what I could from the vines already, it was a rather pitiful picking haha but I just wanted to start on my first wine batch so I'm better prepared for next year. Does powdery mildew get fully expunged during the winter (we have a lot of frosts and the temperatures hang around freezing for at least a few weeks), or does it lie dormant and return year after year? I'm wondering if I ensure the vines are healthy and well-watered next year, perhaps next the crop might improve?

I'll look into the govt or university resource idea, thanks. There's a biodynamic vineyard somewhere in town that I could potentially volunteer at for some know-how.

In the meantime, I'll cross my fingers that the 2.5 litres of wine I managed to save from the grapes is actually drinkable haha.
 

Johny99

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Good luck with what you picked. Sorting and destemming by hand is hard work that should be rewarded.

Once you have mildew, it over winters and is always around. The key is humidity and temperature. A light breeze can go a long way in prevention. You can pluck leaves to provide air flow and that can help.

In the US sulphuric sprays are allowed for organic growing. Not my favorite thing to go spraying around. Talking to the local bio folks is the best idea. They should know what works in your area.
 

WillNic

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That's a shame, I was kinda hoping the winter might wipe the slate clean so to speak! Good point about airing things out, I'll definitely get on top of the trimming next season.

I believe they use sulfur sprays here in NZ as well, but as you say thats not the most ideal solution. Will let you know whether I hear of any less unpleasant treatments!

Cheers,
Will
 

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