American Rootstocks question

I know that American rootstocks were instrumental in helping the French wine industry stay alive in the 1870s. But I also know that there was a serious phylloxera problem in the Calif in the 1980s. If American rootstocks are resistent, why was there a problem in CA? Were these not American rootstocks?

Not sure if this helps:

http://vines.org/Docs/Text/WINE_Encyclopedia_phylloxera.htm

Response to Phylloxera

1875-1885 Flooding affected areas and chemical treatments (notably carbon disulfide) are marginally effective.
1883-1890 Vitis vinifera is hybridized with various resistant American varieties of Vitis, but no acceptable varieties are developed.
From 1872 The first experiments to graft French scions on to rootstocks from 13 varieties of American vines are followed by exploring different combinations of scions and rootstocks, a process that continues today.
1885-1900 Grafted stocks gradually replace direct-growing Vitis vinifera. Concern about effects on the quality of the wine is satisfied by comparisons in Burgundy, where replacement is done as vines are affected, thus allowing comparisons of wine made from grafted versus ungrafted plants.
1900-1980 Virtually all European grapevines are switched to grafts. France and Italy are first (Italy has more expertise in grafting), Germany is last (with the major replacement occurring only after 1945). A handful of situations remain where ungrafted vines grow in Europe, although they are still common in some parts of Australia and in Chile.
1980-2000 Phylloxera is not considered to be a current problem until a new outbreak of disease starts in California. Most California grapevines have been grafted on the rootstock AxR1 (a hybrid of vinifera and rupestris), which is not highly resistant. The majority of California grapevines have to be replanted on more resistant rootstocks.

There are many different rootstocks available. They all have different levels of resistence to phylloxera, nemitodes, and drought. Being resistent does not make it impossible for the plant to be impacted under some conditions. Give me a fire resistent material and bet me $1000 I can't make it burn.

Jon - a lot of this was discussed in a thread last week. Here is a link: http://www.wineloverspage.com/forum/village/viewtopic.php?f=3&t=38170

Today’s Phyolloxera resistant rootstock might not be tomorrow’s Phyolloxera resistant rootstock. As Steve did mention just after France was “hit” California started feeling the affects of Phyolloxera (late 1870’s). Since a lot of the “research and development” already begun in France, we basically just took the rootstocks developed by French hybridizers with the help of their American counterparts. A X R1 seemed to work in France so we used it here. In the 1930’s I believe Burgundy growers were seeing a “weakness” in the A X R1 rootstock, (I’m not quite sure if other wine growing regions in France were having the same experience), but shortly afterwards The French Agricultural Dept took it off their “approved” rootstock material. At the same time data was being collected on research done with various rootstocks in California and basically they concluded (unfortunately) A X R1 was basically a good “all-purpose” rootstock for California. But then in 1983, a “mutated” form of Phyolloxera came to visit California.

Salute

Thanks everyone. That a “mutated” form of Phyolloxera came to visit California makes this clearer. And Howie - I'm sorry I missed last week's discussion; I don't like being the guy that asks questions that were recently asked.