Marquette shutting down early

[RonObvious]

I'm having trouble figuring out why my Marquette vines seem to be closing up shop for the season already. The clusters look nice, but are only at 14-15 brix, so they have at least a couple weeks (maybe more) before they're ready to harvest. Meanwhile, the vines themselves are dropping leaves. I don't see any evidence of disease and I've been keeping up with the spray schedule. Like a dummy, I didn't do a petiole test this year (and I'm regretting it), but we did one last year and it showed nothing major - just that the vineyard needed nitrogen and boron, but of which I have since amended. All other varieties in the vineyard are doing great - still have dark green leaves and look healthy. The Marquette seems to think it's the end of September when it's really only the end of August.

 

[wood1954]

Looks like some of my vines. The extension office said it was phomopsis. Not much you can do now. Next spring after pruning try using lime sulfur just before bud swell. Then all we can do is make those early sprays. Are you using mancozeb and captan?

 

[RonObvious]

Thanks - out of curiosity, when you say it looks like some of your vines, are you referring to Marquette too? Or other varieties? What I mean is, I'm not even sure just how abnormal this is for Marquette. We've been growing it since 2017 and the vines always look pretty tattered and tired by the time we harvest (as opposed to some other varieties, like Petite Pearl, that still have nice dark green healthy leaves at harvest). It's just that it's happening earlier than ever this year. It has been a very hot and dry summer here in New England this year. I'm wondering if there's any possibility that the vines have indeed accumulated their required Growing Degree Days and are, in fact, going to bed early for the year? Or maybe that's wishful thinking, I dunno.

We did have a minor phomopsis issue at the other end of the vineyard, with a different variety, last year, but I think I got that under control. I did indeed dormant spray the entire vineyard with sulfur. Mancozeb (Manzate) is my early season fungicide of choice after bud break and they were sprayed with it several times. I also hit the whole vineyard every year in June with myclobutanil (systemic).

 

[wood1954]

Yes I was talking about Marquette. My vines leaves generally stay green and healthy into October. You might want to add Captan to your sprays. Phostrol, tebuconazole and azoxystrobin also work on phomopsis. Just spraying sulfur during dormancy won’t kill the spires.