REPORT OF COMMITTEE ON PUBLICATION 49- 



A variety under congenial conditions of soil, climate, etc., will frequently 

 prove more resistant than one having greater inherent resistance, but which 

 is not adapted to the particular conditions. 



The congeniality existing between scion and stock also influences the 

 resistance of phylloxera. 



Causes like these and many others affect the resistant qualities of vines. 



Department Researches in Vinifera Regions. 



In a survey made by the writer in 1902 to 1903 of the region in which 

 the vinifera is commercially grown in this country, it was found that exceed- 

 ingly serious conditions prevailed. As all efforts to check the devastation 

 of the phylloxera had failed, the United States Department of Agriculture 

 was looked to for aid and in 1904 undertook a comprehensive investigation 

 of the entire subject. 



To afford facilities for systematically prosecuting these and other prob- 

 lems coming up for solution, the United States Department of Agriculture has 

 located and maintained experiment vineyards at Brawley, Colfax, Chico, Elk 

 Grove, Fresno, Geyserviile, Guasti, Livermore, Lodi, Mountain View, Oakville, 

 Sonoma and Stockton, California. 



These were located with special reference to different soil and climatic 

 conditions, higher and lower altitudes, nearness to and distances from ocean, 

 bays and other bodies of water, and to bring out the typical differences of 

 grape products derived in different sections under varying conditions. A 

 mechanical analysis and correlation of the soils in each of these vineyards 

 has been made, and weather records are kept in them to enable us to use- 

 fully apply results for the benefit of intending growers. 



To obtain additional data on such minor differences of soil, climatic and 

 other conditions not found in any of the experiment vineyards and to encour- 

 age others to research work, distributions of vines and cuttings are made 

 to persons willing to report results had with them. 



Species and Varieties of Grapes Under Test in the United States Department 

 of Agriculture Experiment Vineyards. 



All vinifera varieties of importance are being tested on all stocks con- 

 sidered valuable. Of the twenty-three species of grapes native to North 

 America, fourteen have been found sufficiently important to have special 

 attention given them. These are: Vitis aestivalis; v. berlandieri; v. bicolor; 

 v. candicans; v. champini; v. cinerea; v. cordifolia; v. doaniana; v. labrusca; 

 v. linsecomii; v. longi; v. monticola; v. rupestris and v. vulpina. 



These, amongst other reasons, have been selected with special reference 

 to the conditions under which they thrive as natives. 



A description of these species and where they are found native is given 

 in Bureau of Plant Industry Bulletin No. 172. As our researches progressed 

 a number of other species have become represented in the vineyards. In 

 the quest of resistant stocks suited to soil, climatic and other conditions and 

 that are at the same time congenial and lasting stocks on which to graft 

 vinifera varieties many difficulties are encountered. 



For instance, a stock might be suited to the soil, but be so hard to root 

 as to make its commercial use impracticable; again the stock might be suited 



