We didn’t want to leave any leaf unturned during our North America journey, so we went into the mecca of US viticulture – the research department at UC Davis, where Dr Andy Walker heads up the country’s leading research into viticulture. The university is a world leader in enology and viticulture studies and Andy has been involved in the viticulture research department since 1989, giving him an extraordinary overview of the development of the US wine industry. Amanda Barnes interviews him about the challenges of viticulture today including fighting PD and Red Blotch among the other diseases and plagues affecting today’s wine industry, as well as taking a look to the future of viticulture. This is real wine geek stuff, so grab a notebook and enjoy!
Please share this video with any budding winemakers and UC Davis alumni (past, present or future!)
Interview with Dr Andy Walker, UC Davis, transcript
Amanda Barnes: Andy, you are the Viticulture Professor and guru here at UC Davis, can you just let me know from your perspective working in the industry and researching, what are the greatest challenges that we have to viticulture today? In this region?
Andy Walker: Probably water, and people. In terms of the allocation of water, and resources and labour. Redesigning our vineyards so they are more effectively mechanised. Disease and pest control is a huge one, since we have a number of not very sustainable practises to try and control them all, so they have built up a lot of resistence.
AB: And what are the biggest diseases that we are encountering today?
AW: Traditionally powdery mildew, and downy mildew, of course things like phylloxera and nematodes are very serious. Pierce’s Disease for the future of California, I think is a very important one. Although it may never spread beyond its typical boundaries for now, it could and we have to prepare for that.
AB: You have been working very significantly in PD. How widespread is it in California?
AW: It’s fairly widespread, but its not very broadly spread in any given area. So it’s about 4-5% of the north coast counties probably. But some very, very noticeable and famous vineyards are involved. And it does ebb and flow, it can be very serious for a couple of years, and then go back to sort of a dull rumble… The lower southern half of the state is largely affected by it. Most of the southern United States is affected by it, right across to Virginia.
AB: And of course the problem with PD is that it destroys the vine completely?
AW: One of the few diseases that kills grapes fairly quickly!
AB: So, are we going to see a huge wipeout across the country at some point soon? Will this be the new phylloxera?
AW: I don’t think I would call it the new phylloxera but I think in small, regional areas, you would be impressed at what the damage can be – it is very devastating. It is normally about 10-20 vines deep along the certain habitat that allows the bacterial complexes to thrive, and it moves in and doesn’t really move much beyond that except for these funny time when it becomes quite serious and spreads more widely.
AB: And what is the best way to combat PD?
AW: Right now it is controlled by spraying the vector, killing the vectors, and there is no other way to control it besides breeding resistant varieties. We are close to getting some for release [at UC Davis] but it will be a few years yet.
AB: Ok, we will have to hold on tight for those varieties.
AW: They are not bad, they actually taste pretty good now!
AB: You say that people, the growth in population, is a big burden on viticulture, and that’s because of a lack of water?
AW: And the lack of available water I guess, the allocation of water to people. And urban sources, and the environment and then agriculture at the bottom. That water becomes more and more precious as the soils and the climate becomes more drier of course. But for two purposes, one directly, and on indirectly – to leech down salts out of the soil profile too.
AB: And working with more resistant rootstocks… you also said you have been doing project related to salinity in the soil, what have you found there?
AW: Well we are looking for salt tolerance in general, we would like to find a form that keeps it from being taken up at all, but most of the resistance comes from species that partition the salt into the root tissue and don’t send it up into the foliage, and they survive, but at some point they will probably have too much salt in the roots to survive. But we have stuff that will grow in 10-25% sea water right now, so it doesn’t grow very much – but it will survive in those situations.
AB: Excellent, and then the other impact that people have is that we have less labour willing to work in the vineyards, how soon do you think we will see California switch completely to mechanised production methods?
AW: The whole state will probably take years, maybe ten or more, but it is happening already. So, the last couple of seasons we have had severe labour shortages and many areas, they tend not to be the highest quality areas because the highest quality areas can afford to pay more and they attract more attention and more labour, but areas like Lodi, that are sort of stuck inbetween it gets very difficult to manage crews because of lack of people.
AB: What are the differences in vineyard management and the shape and form of the vine when you are trying to mechanise?
AW: We need to redesign our canopies so they are best adapted to viticulture equipment – both the pre-pruning equipment and the leafing equipment, and the harvesting equipment, and for that matter if we go for a non pruned or a box pruned system so they have a device for that as well.
AB: Ok. And obviously a lot of your work is looking into different varieties that are resistant to this, that, and all the rest! What are you going to say would be the future variety for California?
AW: [Laughs] Well, I think if you are going to look at climate, and how it may develop, it needs to have better acidity, better colour, better productivity in some cases, less water need, that will probably come mostly through the root system, but there’s also some adjustment we can do with the foliar level too.
AB: And do you think it will be Cabernet?
AW: No, I don’t think it will be Cabernet anymore! That will be in some areas, we’ll be able to take those characteristics I hope and adapt them into something that is more capable of sustaining itself in the environment too.
AB: But you don’t have any favourite varieties which we might be able to see at some stage?
AW: No, not necessarily. Remember that we have over 5000 wine varieties and we use 20 of them more or less! So, there’s lots of play with! I think from a breeders perspective, it will be nice to redesign some of those and have them more carefully tailored for specific conditions.
AB: So do you think this is an exciting period for breeders right now?
AW: Yeah, for breeders it is the best! There’s finally a demand for our talents, and a need for what we’ve been doing all these years. Whether or not we get them properly marketed and competing with the international varieties is another question.
