62 MANUAL OF AMERICAN GRAPE-GROWING 



triumph over the tiny insect, the industry has had to be revo- 

 kit ionized. Resistant stocks, in their turn, brought innumer- 

 able new problems, many of which are still unsolved. Investi- 

 gations and experiences in rehabilitating vineyards have been 

 carried on for forty years, the results set forth in books and 

 bulletins and yet there are many problems to be solved. The 

 grape-grower in regions infested with phylloxera is always 

 under the necessity of taking advantage of the latest demonstra- 

 tion of practices in the use of resistant stocks. These practices 

 are best studied in the experiments of state experiment stations 

 and the United States Department of Agriculture, and in the 

 vineyards of leading grape-growers, since even those most 

 needing elucidation can be but briefly discussed in the following 

 paragraphs. 



The wild vines of a species are always seedlings and are 

 hence exceedingly variable. The first vineyards of resistant 

 stocks were vines grafted on stocks of wild vines, and the 

 results were very unsatisfactory ; for, naturally, there was 

 divergence in many characters and especially in the vigor of the 

 vines. Also, there was difficulty in grafting, since some wild 

 vines are stout and others slender ; some bear grafts well, while 

 others do not. It soon became apparent that to succeed, 

 varieties must be selected from the different species for vine- 

 yard work. The great task of the experimenter and grape- 

 grower, therefore, has been to select varieties of the several 

 species sufficiently resistant, vigorous and otherwise possessed 

 of characters fitting them to become good stocks. Out of 

 vast numbers tested, a few are now generally recognized as 

 best for the several groups of Vinifera grapes and the several 

 distinct regions in which these grapes are grown. 



Resistant species and varieties. 



The reconstruction of phylloxera-ridden vineyards by the 

 use of resistant stocks is possible only because some species 



