A red leaf day.

I have spent quite a bit of time in the vineyard the past two days.  I am still playing catch up, but I have also started to do some pre-harvest prepping; some leaf removal, a fair amount of canopy management and a little bit of weeding.  There were several, persistent stands of shortpod mustard (Hirschfeldia incana) and spiny sowthistle (Sonchus asper) to be dealt with.  I tripped over a large mat of sharpoint fluvellin (Kickxia elatine) myself, so I think it made sense to remove any large weeds that may get in the way of those who will harvest Vinoland's grapes.
Even though it was a bit toasty out in the vineyard (especially yesterday afternoon) I had an enjoyable time and was even able to stop and have a look at the fruit, the odd insect (including the really odd insect that unexpectedly jumped on me, but which I reflexively flicked away before I could ID it) and the dark red leaf (in the photograph) with the telltale girdling on its petiole.  Darn insects!

The stripper.

The harvest season is quickly coming to a close, so there is very little unpicked fruit left to be seen hanging around the Napa Valley.  TWWIAGE picked and processed their last fruit of 2014 on Tuesday.  In Vinoland only the Cabernet sauvignon is still hanging, but that's about to change come this Saturday.
As of today, the numbers on the Cabernet sauvignon were °Brix 25.8, pH 3.52 and TA 8.0, but since the decision to pick has already been made the numbers are sort of irrelevant.  The weather has turned quite autumnal and the vines have noticeably started to shut down.  I spent most of today pulling leaves, stripping the shoots of all basal leaves to help facilitate a quick and clean harvest.  And that's what I will be doing tomorrow also.

My girdle is killing me.

Whilst walking through the vineyard late this afternoon, checking on how the Syrah vines are shutting down for the winter, I noticed a red leaf. I did not panic, instead I checked the leaf's underside.
A ha! As I expected I found insect damage: girdling of the petiole. Now in this neck of the woods there are two main suspects for such crimes against vines; the Buffalo Treehopper (Stictocephala bisonia) and the Three-cornered Alfalfa Hopper (Spissistilus festinus). Damage to the vine occurs when continuous feeding punctures, resulting in the interruption of the movement of materials to the leaf, reduce chlorophyll production and cause anthocyanins to become the dominant pigment remaining in the leaf. The reddish leaves look like those of Leafroll virus, hence my concern upon espying the offending leaf.
It is obviously not a big problem, seeing as this is the only red leaf I have seen in the vineyard, but it was a momentary cause for concern. After all, you need healthy vines to make yummy wines.