Frontenac grapes shriveling up

[MEngle]

For the second year in a row, most of my Frontenac grapes are shriveling up.(this week) I'm sure a few of the grapes have some disease, but not all the ones that are shriveling up. Has anyone had this problem with frontenac?

They do have weed/plant pressure, as some of them grew around bee balm plants i had for the bees. But I also have Brianna, Marquette, St Pepin, Steuben, LaCrosse which do not shrivel up. The soil has had no additives/amendments and was cleared 7 years ago. I do not spray weed killer.

Anyone got ideas of what my next move is?

 

[balatonwine]

Grape shrivel can be the result of several different causes. This may help explain them:

http://wine.wsu.edu/2006/11/06/berry-shrivel-all-the-same/

 

[MEngle]

I am noticing that many of my Frontenac vines have very few leaves, so they would be getting sun all day. I need to figure out how to get the vines to grow more leaves I guess.

 

[balatonwine]

Defoliation might be indicative of a more generic problem. The vine may auto-shed leaves that are diseased, for example (i.e. fungus), which may result in not enough leaf area to mature the fruit. So it shrivels.

 

[berrycrush]

I am noticing that many of my Frontenac vines have very few leaves, so they would be getting sun all day. I need to figure out how to get the vines to grow more leaves I guess.

could be drought?

 

[user 36973]

I've seen this problem before with another grower. Grapes were good going into Labor day weekend and shriveling up afterwards. Tried to salvage wine out of them but it was full of VA and dumped it. I'm thinking it was sour rot that ran amock through the vines.

 

[BigH]

For the second year in a row, most of my Frontenac grapes are shriveling up.(this week) I'm sure a few of the grapes have some disease, but not all the ones that are shriveling up. Has anyone had this problem with frontenac?

Can you post a pic? Did you measure the brix, pH and TA before they started shriveling up? What were they at?

Cornell University had an article about frontenac in last year's "From Veraison to Harvest". They meantioned that it needs to hang and that it will start to shrivel a bit and will look pretty bad when it is harvested. You may have just gone a bit too far.

Do the skins look like they have been punctured or split? Any rain in the past week or two?

H

 

[FrontenacMan]

Where are you located? I had that problem this year with my Frontenac vines. I'm located in Wisconsin. I got twice as much of a yield last year as I did this year. I lost much of my grapes to the same thing you are describing but it started happening before veraison. I'm tending toward the very excessive amount of rain we got here this year and the odd weather and rain patterns. I have an automated irrigation system and had to keep manually turning it off and on to accomodate the rainfall and not overwater. The grape clusters that were good were those that had more air flow.
As far as leave production, I never have a problem with not enough leaves. Frontenac are vigorous growers. This year with all of the moisture (rain) they really went crazy and I had to do summer pruning quite a bit. I think the heavy growth may have what caused my issue. But bottom line is you may just be falling victim to the weather as I did this year.