Sunday, April 25, 2010

Season is late, but nice weather hanging around!

Late season, yes, but it could be worse!

We've had a bit of an Indian Summer here, with a frost on April 10th, and then warm weather afterward.

While the season from September to January was miserably cool, with monthly temperatures being well below the long term average, February and March were slightly above average, and April is shaping up to be a decent month as well.

For those grapes that have kept their integrity through now, this is good news. We had 6mm of rain yesterday, but today was a nice warm and windy northwester, which has helped to dry out the clusters and should prevent an infection period for Botrytis from occurring.

There may be life yet in this difficult vintage for Canterbury!!

Sunday, April 18, 2010

Curing virused vines?

I've just read some exciting news in the December/January issue of New Zealand Winegrower (yes, I know it's taken me a while to get around to reading it!! :-)

Some work being done by doctoral student Elaine Chan, Mike Pearson of the University of Auckland and Robin MacDiarmid of Plant and Food Research (pages 80-82) suggests that it might be possible to cure vines of virus diseases, or at least, be able to prevent virus from spreading from the infection point.

Viruses such as Grapevine Leafroll are major issues to grapegrowers around the world, so the thought that this might be able to be done is pretty fantastic! At the moment, infected vines are pulled out and replaced, and in some cases, the vines next to the infected one are removed as well, to lessen the possibility it may spread.

If researchers can figure out how to get plants to ramp up a defense mechanism against viruses, much as animals do, then the implications for grapegrowers would be tremendous (perhaps both pro and con!).

The idea is to duplicate the action of a protein in animals that signals the presence of viral agents. That protein would tell the surrounding tissue to stop making proteins, which the virus needs in order to replicate itself and spread through the rest of the plant. If that was done, then the plant could use other means to stop the virus from spreading from the infection point, say, by a hypersensitive response, where the tissue immediately surrounding the infection point dies, thereby isolating the virus. This response is well known in the area of fungal infections, for example.

They are also mooting the possibility that a plant equivalent of interferon could be developed, which would stimulate the plant to produce more of these signalling proteins and therefore stop the virus in its tracks.

These are not new ideas (see this article "Is there a plant interferon?"), but it's interesting to see that people are looking at this from the standpoint of grapevines.

If, and it's still a big "if" at this point, this was able to be accomplished, vines would be able to stop infection before it started, and infected vines could be cleansed of existing infection.  It remains to be seen if such a thing could be done with today's vines, or if new vines would need to be developed which have this capability.

As well, sometimes viruses can help to make better quality wine. The Mendoza clone of Chardonnay, for example, is thought to produce lots of the smaller berries it's well known for because it is infected with a mild strain of Leafroll virus. I'm sure there are other instances where the virus (or related "disease" organisms) may be holding back the natural vigour of vines, or changing the fruit morphology in some way that led to a clonal selection. Sometimes, you have to take the good with the bad!!

Saturday, April 10, 2010

What's happening in Marlborough?

Just got back from a tour through Marlborough with the Lincoln University Viticulture I students!

And an eventful time to be going through and talking with a number of people in the industry, working in large and small outfits.

Overall, the prognosis is good for the industry, in that regional yields are looking to come in slightly below the predicted total, which means there won't be an additional lump of wine to try to sell over the coming year. The other news is that everyone is really happy with the quality of the fruit coming in - the season was pretty cool, but the last weeks of the season have been ideal, and this combined with the lower crop loads (some by the effects of nature at fruit set, but some also due to people keeping crop loads down). Good news indeed!!

The big boys were in the early phases of harvest (getting close to 50% about now), but some of the smaller outfits (Fromm, Staete Landt) were pretty much through!

I've more detailed info (in snippet form) at http://twitter.com/sabrosiavit