Pay attention!

With the vineyard being sprayed for the final time last Thursday, requiring a 48 hour no re-entry time (or re-entry interval, REI), and being distracted by four little feathery chickies, I hadn't noticed the onset of veraison in the Cabernet sauvignon vines.  Well, here we have it.  Whether I am paying attention or not, the grapevines will carry on doing their thing.  Thank goodness.

How green is my valley.

I don't know if it's me, the light quality today, or the fact that Vinoland's grapevines got a little extra TLC last night, but everything in Vinoland just looks wonderfully verdant today.  The Pinot grigio grapes are definitely a little shinier: I'll explain.
In the never ending quest to produce good quality grapes from disease free vines, preventing pests from damaging the grape crop calls for a combination of techniques, or integrated pest management (IPM).  Along with cultural practices, sometimes chemical control, the use of pesticides, can be more effective in controlling pests (in the greater context of a broad IPM strategy).  Yesterday evening was the first time Stylet-Oil (SO) was used on the grapevines (with a little Mettle® fungicide thrown in for good effect).  SO is a little more effective against powdery mildew (Uncinula necator) (PM) in cooler growing seasons (like the one the Napa Valley is experiencing this year) versus the more conventional use of sulphur.  Sulphur needs warmer temperatures to volatize (65°F is the recognised minimum temperature required for sulphur activity against PM), whereas SO is not temperature dependent and so it acts as an eradicant, protectant and, most importantly, an antisporulant 24 hours a day.  In layman's terms, SO stops spores from growing, and insects from breathing.  And it makes baby-grapes shinier.

Bringing up the rear.

I was kept busy all day today pulling leaves in the Pinot grigio vines in preparation for the installation of bird-netting.  About mid-afternoon, feeling a bit peckish, I took a break and wandered over to the bramble patch to have a quick snack of sun-warmed blackberries.  Lo and behold, I discovered that the Cabernet Sauvignon vines had started to go through veraison.  In fact, some of the clusters are far more purple and advanced than the one I photographed.  Go grapies!
And please ignore the cleistothecia in the photo, I am.  (Until next spring, that is.)

Midyear report.

It's the 1st of July already, wow!  Everything in the vineyard looks good. Fruit set in the Syrah, Cabernet sauvignon and Pinot grigio vines looks normal.  The berries are small and hard - still more than a full month away from the onset of veraison.  The past 12 days of toasty weather were not quite hot enough to end the risk of infection from powdery mildew. High temperatures can harm the fungus, but only two days got over 95° F, so sulphur applications will still be necessary for a little while yet.  All in all, I'm pretty pleased with this growing season.  So far, so good.

And last, but not least...

...veraison in the Cabernet Sauvignon vines has begun, albeit very sporadic.  Caught in all their blushing glory late yesterday afternoon, this particular cluster of grapes includes a few shot berries, the odd dead flower part and lots of pesky powdery mildew cleistothecia.  Lovely, (not).

Win early!

While everyone is in a tizzy about the appearance in the Napa Valley of the European grapevine moth, and understandably so, there are many other threats to the vintage that the winegrower must face every growing season. Just this past Monday (May 10th) we had an exceptionally late spring frost. Rain is forecast for this coming Monday and, with bloom nearly upon us, heavy rainfall now would be disastrous for fruit set.
Possibly the biggest headache for winegrowers every year is powdery mildew (Uncinula necator), a fungal pathogen that infects all green, succulent tissue on the grapevine, including leaves and young berries. Powdery mildew (PM) can cause extensive crop loss and poor wine quality if left untreated. Temperature is the most important factor influencing the development of PM: it positively thrives in temperatures between 68-81 degrees F. Vitus vinifera cultivars vary in susceptibility to PM, but the principal control method for preventing infection in all cultivars is the application of sulphur in wettable and dust forms.
It is looking like 2010 is going to be a bumper year for this particular disease as we have had no hot weather this spring. So far this year, each sulphur application in Vinoland has been followed by a rain event making it difficult to get the upper hand in preventing further germination of conidia. But, perseverance is the key and so Vinomaker was out spraying the vines today and could oft be heard muttering to himself the mantra, win early.