In a very real sense, this 'experiment' was carried out unintentionally; and
the result was a disaster. A huge % of the French vineyard stock was wiped
out. As another poster mentioned, there are some vines that survived - but I
don't believe it had as much to do with soil type as it did isolation; small
vineyards that were remote from others, with no equipment or worker traffic
to and from infected vineyards, 'survived'. Bottom line - the 'resistant'
varieties do exist; the natvie North American root stock, which evolved
along with the little critters. In the dense vineyard regions of the world,
it is a necessity to graft.

Here in the US, and I believe to a lesser degree in Europe, there are many
recently planted vines that are not grafted - but only in regions that were
previously uninfected, and are isolated from other vineyards. I have one
such vineyard of self-rooted vinifera. I don' allow any equip from other
vineyards, and we do all the vineyard work ourselves. Our county has only
one reported instance of phylloxera, and is quite vigilant about imported
plants and material.



"UC" wrote in message
oups.com...
Why don't they just let the vines grow (i.e., not graft them onto
American stems), and determine by natural selection those that have a
natural resistance to Phylloxera? Surely that trait exists in SOME
plants!