Virus "Threatens" Napa Vineyards.

I know it's from Evil Alice , but I thought the story and some of the implications/reactions to the problem were interesting.

http://www.sfgate.com/cgi-bin/article.c ... 1E8FD5.DTL

If it means reduction in sugar levels (and therefore final alcohol levels) for California wines, I'm all for it. Bring the leaf roll virus on!!

-Paul W.

Leaf roll virus is present in most South African vineyards and there is a huge effort to replace with virus free material.

Leaf roll virus has been blamed for 'off' flavours sometimes found in South African wine including the 'rubbery' tones reported by some.

[David M. Bueker]

If it means reduction in sugar levels (and therefore final alcohol levels) for California wines, I'm all for it. Bring the leaf roll virus on!!

Of course that's not all it means. If the grapes have lower sugar but are also somewhat green then you get lower alcohol, nasty wines.

Everything I have read about leafroll indicates that there are no hard and fast conclusions that can be made. It exists all over the world and has for some time. Some vines are infected and never show any impact. Those that show impact can see reduction in yields of around 20% and fruit that matures later. Many of the advantages of "old vines" are thought by some to just be the impact of leafroll. As leafroll does not kill the vine, it has historically not been a reason to replace.

Indeed, especially with vieilles vignes of Carignan, Petite Sirah and several other varieties, leaf roll virus can actually be quite beneficial to both the vine and the wine. The problem is largely with younger vineyards where leaf roll virus not only cuts back on the crop (well past whatever cutting back is considered desirable) but to add a rather exaggerated note of bitter herbs to the wine.

Best
Rogov