90 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



grafted on resistant stock, when properly handled, produce larger crops 

 of better grapes than vineyards of ungrafted vinifera. 



This bulletin is issued, therefore, with the object of describing what 

 seem to us the best methods of procedure, especially as regards the 

 mechanical details of grafting, planting, and nursery work. 



Some of the chief causes of failure in unsuccessful grafted vineyards 

 are: 



1. The use of a resistant variety which is unsuited to the soil and 

 climate of the locality. Resistant varieties are all derived from one of 

 several species of wild vines indigenous to the United States east of the 

 Rocky Mountains. All these species are much more difficult to suit in 

 the matters of soil and climate than the European wild vine, Vitis 

 vinifera, from which all our wine and raisin and most of our table 

 grapes are derived. This question of adaptation to local conditions is 

 only touched on here. 



2. The use of an insufficiently resistant variety. Varieties of all 

 degrees of resistance exist, from almost absolute immunity to a degree 

 of resistance so small as to be of little practical value. Some with a 

 medium degree of resistance, like the Lenoir, will give fair to good 

 results when grown under the most favorable conditions, but fail more 

 or less completely when attacked by phylloxera under less favorable 

 conditions. This question of resistance is not discussed fully here, but 

 all the varieties recommended have sufficient resistance under prac- 

 tically all conditions that exist in Californian grape-growing districts. 



3. The use of unselected resistants. Many of the first resistant vine- 

 yards started in California were planted with cuttings of wild Riparia 

 vines collected in Nebraska and other native habitats of the species. 

 Wild vines are nearly always seedlings and, therefore, vary very much. 

 Each vine, though of the same wild species, is in fact a different variety 

 of the species (using the word variety in the horticultural sense). For 

 this reason, wild vines differ greatly in many respects, and especially 

 in the important character of vigor. Though a few of them may be 

 sufficiently vigorous to make good grafting stock, many of them are 

 much too weak or slender, and none of them are likely to be as good as 

 the best named varieties which have been selected from a vast number 

 of seedlings on account of their exceptional vigor and the possession of 

 the greatest number of those characteristics which are desirable in a 

 grafting stock. Most of the earlier resistant vineyards show great 

 variation in the vigor and bearing of the vines due to this use of wild 

 cuttings, and none of them give as good results as they would have 

 given if grafted on a good selected variety of stock. This variation 

 in vigor, bearing, and longevity is often found in more modern vine- 

 yards, and is due to a mixing of varieties by the nurseryman or the 

 grower of resistant cuttings. 



