214 MANUAL OF MODERN VITICULTURE. 



grape-grower who already has -bearing vines and to the 

 intended grape-grower who is engaged in planting his vines. 

 Each succeeding year sees new vineyards and new localities 

 attacked, and the grape-growers who believed their vines 

 safe on account of the richness or sandy nature of their 

 soils, the practice of irrigation, or the isolation of their 

 vineyards are gradually being forced to change their belief 

 by the sad fact of the death of their vines. Yet there are 

 still many who fail to realize the true nature of this disease, 

 and even now there are growers who are planting varieties 

 of Vinifera on their own roots in localities adjacent to 

 infected districts, and even in the infected districts them- 

 selves. 



Even those who are thoroughly persuaded of the neces- 

 sity of establishing their vines upon resistant roots are in 

 doubt as to what species or variety to choose. 



When the phylloxera first invaded the lower parts of the 

 Sonoma and Napa valleys, over twenty years ago, the vine- 

 yardists were completely unprepared for it, and unable to 

 combat it in any way, so most of them allowed the insect to 

 have undisputed sway, with the result that the vineyards 

 disappeared. A few of the more intelligent growers, how- 

 ever, tried the method, first practised in France, of planting 

 resistant stocks. The principal varieties planted were 

 Riparia and Lenoir. Other varieties were planted in small 

 quantities by a few growers, but most of them are at present 

 of little interest. The results varied widely. Though .a 

 certain number of vineyards were fairly or even perfectly 

 successful, the majority were total or partial failures. This 

 lack of general success was due to three principal causes: 



1. Many of the soils and locations were unsuitable for the growth 



of either Riparia or Lenoir. 



2. The Riparia cuttings used were not of one variety, some being 



very small growers, unable to support a large Vinifera. 



3. The Lenoir is not sufficiently resistant in all soils, and therefore 



failed to give full crops on any but the best soils. 



To these should be added, in many cases, ignorance of the 

 methods of planting and grafting resistant stocks. 



Ten or fifteen years later the coast valleys south of San 

 Francisco, which the vine-growers had hitherto considered 

 immune for some mysterious reason, were attacked. They 

 were just as unprepared as the vine-growers of Napa and 



