Grapes shriveling & bugs moving in - pick now?

[mattyc]

I've been measuring Brix and pH every other day on my three rows of Marquette. The first row is on TWC and the other two are GDC. The TWC row has consistently been about 2-3 brix ahead of the GDC rows and been looking great; today it measured 25 brix and pH is 2.87 (9/3 and 9/5 it was 24 brix).

Today I just saw that a fair number of grapes are shriveling and bugs are showing up... flies, ants, asian beetles, wasp. It seems like they shriveled first, and then the bugs showed up - not the other way around (I've dealt with a lot of wasps before.) Is this botrytis? Does this mean PICK NOW!?!

Thank you for any thoughts/suggestions!

-Matt C

 

[TOMMARIANI22]

It looks like bird damage trying to pick at it but can't get to it because of the nets.. that's the reason for the bugs the flesh is exposed. Definitely not bortrytis , kinds of weird how your pH is so low but sugar accumulation is still high? Have you had a really dry year? It could just be dessication of fruit and that would make sense to why your sugar is High but pH still low.

 

[mattyc]

Thanks for the quick reply.

I really don't think it's birds... 1) it's happening on bunches that are deep in the canopy that the birds just couldn't get to - just the same as the bunches close to the netting, and 2) I've been watching things closely and the birds just haven't been in the grapes this year.

No, it hasn't been a dry year (I'm in East-central MN). It was wet June & July, dry in August, and then we finally had a lot of rain early this week.

I went out and picked a full cluster(an "average" cluster) and took some data with much more fruit this time...

soft/shriveled berries - 31 brix, 3.11 pH (not enough juice to measure TA) - Yes, 31 brix !?!?
"firm" berries - 24 brix, 2.90 pH, 13 g/L TA

I think it's time to pick (last year I harvested at 23 brix, 2.76 pH, and 13.5 g/L). I'd just like to know what it is I'm seeing...

It's times like these I wish I had somebody experienced to look over my shoulder and show me how to do things; thanks for the input here on these forums!

 

[havlikn]

We are in Wisconsin. With all the rain, there has some berries rupturing from all the water the vines soaked up. Could be that

 

[CK55]

Aside form the few bad grapes those are some really nice looking grapes.