Saturday, February 27, 2010

Netting -What a pain, but we have little choice!

Okay, the nets are on! With such a small vineyard, it didn't take all that long, but it is the clipping of the nets that takes a lot of time, and thank goodness we had wonderful friends that could help!


In the photo above you might be able to see that we have netting that goes over a single row, with the edges joined at the bottom. We roll them up and clip them in place with curtain hooks.

It's essential that there are no gaps in the netting, even very small ones, as birds are very clever and will search for any access point. 

One problem is that sometimes the net is resting against clusters that stick out into the row - birds can sit on the net in these places and peck at the fruit. So outriggers, or something that pushes the netting out away from the fruit, are sometimes used. Most often, some sort of horizontal support is used to push apart the first foliage wire, which then keeps the netting from getting too close to the fruit. We haven't done this at our vineyard yet - we're seeing how it goes, and will try to tuck shoots out to push the nets. If necessary, we will be fabricating some sort of stick to push out the foliage wires, and thus the nets. However, I'm hoping it doesn't come to that!!

Hopefully, this is the only view of the grapes that the birds will get!!

Tuesday, February 16, 2010

Prepping for harvest

After dealing to the powdery mildew in our little vineyard, there were a few things that we needed to get ready in the preparation for eventual harvesting!

The first order of the day was to give the vineyard cover crop a good mow! For me, this is mainly a comfort thing, as it's not that nice to walk through the vineyard if the grass is very tall. This is especially true if the grass is damp from morning dew!

As well as this, the shoots needed a general tidy-up, as they had grown a bit since the last time we were through, and were getting a little tall. This is despite it being not that long ago that we did the shoot topping and positioning. We had some rain recently, and the vines were responding with a fresh spurt of growth.

Then, as the grapes were just starting to colour up (Pinot noir and Pinot meunier), it was time to get the nets on.

Timing of this is a bit tricky, as if you put the nets on too early, the vines grow shoots and tendrils through the netting, which makes it a lot harder to take the net off after harvest, and the vine-y bits cause the netting to tangle.

If you put the nets on too late, the birds discover how yummy the grapes are, and they'll pick off the grapes as they are colouring up. If you're not looking closely, you might wander through the vineyard and think that veraison is being delayed, but in reality, all the coloured berries are being picked off by the birds, leaving little clue that ripening is at hand! As a result, you can lose a lot of crop! Also, if the birds discover the grapes, they will tell their family and friends, and in a matter of hours, decimate the crop of a vineyard.

So in putting on nets, it's better to err on the side of being too early!!

So that's what we've done - just a few berries are starting to turn, so we put the nets on last weekend.

 
Side netting being attached to the upper foliage wires. These lucky workers are the front line to defense against birds damaging the fruit!

The job is not done, however! We still need to finish clipping the nets - that is, making sure there are no holes in the netting that birds can get through. And they're very clever at getting through spaces you wouldn't think they could!!


Saturday, February 6, 2010

Powdery mildew

I've just been spraying our vines with sufur to control powdery mildew. This nasty disease, caused by the fungus Uncinula necator, infects green tissue on the vine, most commonly showing up on leaves, but also fruit and shoots.

Powdery mildew on a shoot pre-bloom. If the leaves are infected while young, you see this cupping of the leaf margins

Powdery mildew infection on a green shoot.


Powdery mildew infection on a dormant cane. The fungus cannot infect dormant vine material, so this problem came about during the growing season.

Control is through the application of sulfur, primarily, as this is a pretty soft compound for the environment. There are synthetic compounds available, the most common of which fall into the demethylation inhibitors (DMI) category. However, as long as the green tissue has a covering of sulfur, infection by the fungus is prevented. This requires repeated application through the season, to cover new growth, and also re-cover sulfur that has been washed off, or which has all volatilised. DMIs are great, but there is concern about resistance developing against them, so their use is limited to a certain number of applications per season.

It is the gaseous form of sulfur that is active against powdery mildew, so with heat, the solid sulfur is converted into sulfur dioxide (SO2). However, like with any disease spray, good coverage is essential!

Powdery mildew likes warm and dry conditions: in fact, heavy rain can help prevent infection by washing off the spores!

Careful monitoring for evidence of the disease, which usually starts in those places where the sulfur sprays can't reach (hence the need for good canopy management!), can delay the timing of the first and subsequent sprays, reducing their frequency. However, the disease is like an opportunist - miss one spray and it's likely to take over!