REPORT OF COMMITTEE ON PUBLICATION 69 



PHYLLOXERA RESISTANT STOCKS IN CALIFORNIA. 



By F. C. H. FLOSSFEDER, 

 Viticulturist, University Farm, Davis, California. 



When the phylloxera appeared in France and after it had done a con- 

 siderable amount of damage, it was thought the crossing of the non-resistant 

 vinifera varieties with resistant American species would save the industry. 

 This was attempted and we got what is called the direct producer, of which 

 we find a few here and there, grown at the present time. The results ob- 

 tained in this way were, for several reasons, not satisfactory. The grafting 

 on resistant vines was commenced at about the same time, but this 

 also was not accompanied by the results expected, because a good many 

 stocks used at that time were not resistant enough or not suited to the soil 

 in which they were planted. Very often they were very weak growers, and, 

 as the years passed by, the field grafted vines were pulled up, because they 

 proved to be unsatisfactory in several ways, and experimenters narrowed 

 down their very large collections of species, varieties and hybrids of Vitis 

 to the comparatively small number of stocks used at the present time. After 

 long years of hard and systematic work, it may be said, that at the present 

 time there is in France a resistant stock suited to almost every kind of soil. 



Here in California, things are somewhat different. Grape growing in 

 this country is comparatively new, the phylloxera appeared much later and 

 climatic conditions here do not allow the phylloxera to destroy the vineyards 

 so quickly as in Europe. There are Muscat vineyards here, which are known 

 to have been infested with the insect for fifteen years, but are still in exist- 

 ence and giving good crops. 



To a certain extent, we do benefit by the experiences gained in Europe. 

 However, very often it happens that a given stock, which does well in France, 

 seems to give no good results under about the same conditions in California. 



As no systematic work had been done along this line of investigation, 

 Prof. F. T. Bioletti, of the Division of Viticulture, College of Agriculture. 

 University of California, in the soring of 1910 commenced a series of bench 

 graftings to supply material for the stock testing of blocks "B" and "F" of 

 the Davis, and "A" and "B" of the Kearney Experiment vineyards. Of the 

 9,750 bench grafts made, 5,612 or 57.55 per cent grew. The variation in 

 percentage of the various combinations which gave successful unions and of 

 their vigor, was very great and indicates, first, suitability of these combina- 

 tions; secondly, the general suitability of each stock for nursery work; 

 thirdly, the general ease of grafting for each scion. 



During the summer of 1910 these bench grafted grape vines received 

 ordinary nursery care. They were dug up in the fall, and planted in March, 

 1911, in the field with the unions an inch above the surface of the soil. 



During the summer of 1911 they were watered twice; the soil was well 

 cultivated in order to give them a good start, which they made. In Novem- 

 ber, 1911, we had a very bad early frost, and owing to the fact that the vines 

 were still growing, they froze down to the ground and, in some few instances, 

 even below the union, rendering the plants useless. 



