So there has been a lot of talk around the 2018 Bordeaux vintage as those who were organic lost a lot of crop to Mildew. In general, Mildew is treated by Copper Sulphate, which I believe is Organic. https://www.mcgill.ca/oss/article/you-asked/what-bordeaux-mixture. IF this is the case, why would those practising organic not use this? Is it due to the concerns on the environment? Thanks
Here is a good read RE this topic: https://www.winespectator.com/webfeature/show/id/Is-Copper-Safe-for-Wine
Vignerons also face limits as to how much copper they can use (used to be 6 kg/ha/yr over five years and is now down to 4 kg/ha/yr over 7 years). Rain will wash away the treatments, so it can become ineffective very quickly. CF and CS are also very sensitive to mildew (although ME tends to fare better with powdery mildew). When you already had crop losses at 40% in some areas due to frost, it wasn't worth using their copper allotments to save that small of a crop.
Just went down a rabbit hole and found this also: https://thesourceimports.com/scifri-copper-treatments-european-vineyards/. And this: https://www.ncbi.nlm.nih.gov/pubmed/19226754. It seems the question has been asked since before the turn of the century and the financial and/or effective viability questions remain. I think whoever is deciding the "organic" criteria are sympathetic to the market repercussions as the scientific community is resoundingly in agreement that the copper levels in soil are not natural and debilitating to the environment.
I had a very interesting conversation with Mike Warwick about this topic a few years ago, as Europe was starting to panic on copper buildup and South Africa was showing promise on more sustainable agricultural methods. The soils in most of the Western Cape are pretty ancient and don’t actually have much copper in them at all. He said that he could use copper freely in his Vineyards and wouldn’t see buildup for a couple of hundred years (though he had no motivation to do so, as there aren’t mildew problems at present in his Vineyards).
I guess the point is that farming with global standards doesn’t really make any sense. I’ve heard biodynamic farmers say “you know, I’m in a completely different hemisphere than Rudy Steiner was in” and leave out a preparation because it wasn’t something they needed or had access to.