Vinegrowing Course - Day 6

Today was the penultimate session of the vinegrowing course I've been attending and the main focus was pest management. It was also time to say goodbye to Chris Foss, who would be retiring from Plumpton College just before our final session, so this would be our last session with him. Thus we thought it might be appropriate to have a group photo taken with some of the course attendees, out the back of the pub where the morning theory sessions is held.

I hadn't realised when I'd first started the course what an important figure Chris has been in the English wine industry. The wine department at Plumpton College was founded by Chris 30 years go, and is the only institution in the country offering these kind of viticulture and winemaking courses. He has taught a whole generation of English winemakers and viticulturists. The list of Plumpton alumni is essentially a who's who of the English wine industry: Simon Roberts (Ridgeview), Dermot Sugrue (Wiston et al), Josh Donaghay-Spire (Chapel Down), Charlie Holland (Gusbourne), Sam Linter (Bolney), and so on.

As such it feels like quite a special privilege to have been an attendee on a course in his final year teaching at Plumpton. He won't be disappearing altogether - Chris plans to focus on research into sustainable viticulture practice.

So - pest control. Pests encompass the full spectrum or organisms which make vinegrowing more challenging, from the very small (viruses, bacteria, fungi) to the large (up to and including deer). Most of the focus was on fungi, in particular powdery mildew, downy mildew and botrytis, which will likely be the main three targets of a vineyard's pesticide spraying programme, particularly here in the UK. The classic treatments are sulphur for powdery mildew and copper for downy mildew. Although in both cases various options for specific products are available.

Interestingly some recent research has shown UV light may be effective in suppressing powdery and downy mildew.

As with the previous session on herbicides, this seems to be a constantly changing landscape, both with regulations (and attitudes) towards use of sprays changing, as well as new threats to viticulture constantly developing.

One of the biggest new concerns in recent years, particularly in the UK, is spotted wing drosophila - a fruit fly inadvertently imported from Japan. Unlike other species of fruit fly which only lay eggs in already rotting fruit, thanks to a serrated ovipositor it is able to lay eggs in perfectly healthy fruit, which can therefore be far more devastating. There isn't really a good solution to this pest currently - there's some possible hope in "dead end hosts" - plants like pyracantha, which can be planted at the edges of a vineyard, and lure the flies away from the vines, but as with many viticulture challenges there is no silver bullet.

In the afternoon practical session Tom talked more about pest management, we looked at things like nozzles used for spraying, briefly touched on the complexities of calibrating tractor / sprayer settings: you have to spray a certain amount of product over a certain area of the vineyard (within legal limits) and so some calculation is required to determine the right tractor speed versus rate of application.

We also looked at some SWD traps, although if I understood correctly these were more for just monitoring the number of the fruit flies present rather than actually being a preventative measure in themselves.

As a practical exercise we then had a go at bud rubbing. This is the process of removing the unwanted buds / shoots from the vines after pruning and tying down have been completed, and once some initial growth has occurred. Usually this is started a little bit later into the season than we were doing today, although it is an ongoing activity. Sometimes buds which were not visible at pruning time emerge on unwanted parts of the vines which can cause various problems. Primarily the issue here is crowding of the canopy, but buds / shoots lower down on the trunk can act as a conduit for downy mildew infections, when the eggs which have fallen to the ground the previous season germinate in puddles and are then splashed onto the vine. I actually seemed to do reasonably well at this with the bay of five vines I was responsible for, mostly by procrastinating and erring on the side of not doing very much, which actually turned out to be mostly the right course of action.

Like the previous session (but in contrast to most of the other sessions before that) it was very pleasant to be out in the vineyard thus afternoon! The first four sessions had been pretty wintry and the vines were mostly in their dormant winter state so it had all been a bit bleak. What a difference a blue sky and a bit of new growth on the vines makes!


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