110 UNIVERSITY OF CALIFORNIA EXPERIMENT STATION. 



Selection. A very serious defect of many resistant stocks is a slender 

 habit of growth. This is true of most of the vines found growing wild, 

 and cuttings from such vines make poor grafting stock for the stout 

 Viuifera varieties, which will produce a trunk four inches in diameter 

 while the stock is growing only two inches. This is particularly true 

 of the wild Riparias. For this reason great care has been exercised in 

 selecting the stronger-growing vines, and at present we have selected 

 Riparia varieties which almost equal Vinifera in the stoutness of their 

 trunks. The best of these are the Riparia Gloire de Montpellier and 

 Riparia Grande Glabre the first of which has given the best results in 

 California. 



Adaptation. The European vine is remarkable among cultivated 

 plants for the wide range of soils in which it will succeed. We find 

 vineyards producing satisfactory crops on the lightest sands and on the 

 heaviest clays, on the dry hilltops and in the low, moist plains. This 

 is not the case with resistant stocks. Some, such as the Rupestris vari- 

 eties, are suited to the driest soils; others, like the Riparia varieties, 

 grow well only in rich, moist soils. The question of adaptation, then, 

 of resistant stocks to various soils is of the greatest importance if we 

 are to obtain the best results. 



After rejecting all unselected and unnamed varieties, such as the 

 ordinary Rupestris and Riparia, which have caused so much disap- 

 pointment and loss on account of their poor growth, and all insuffi- 

 ciently resistant varieties, such as Lenoir, which have succeeded only 

 in the richest soils, our choice of a resistant for a particular soil, climate, 

 and scion must depend on its qualifications as regards affinity and 

 adaptation. 



After testing thousands of varieties and hybrids originated in Europe 

 and America, a few have been selected as the best for practical pur- 

 poses. In France a fairly good resistant stock has been found for 

 nearly every soil. In California little systematic work has been done 

 in this respect, and we still have the intricate problems of adaptation 

 to solve for most localities. We can, however, profit to some extent by 

 the experience of Europe, and some of the best varieties have been 

 partially tested here and give great promise. 



Disinfection of Cuttings. 



The most effective method of treating cuttings suspected of being 

 infested with phylloxera is to expose them to the fumes of bisulfid of 

 carbon. The treatment with liquid insecticides is not nearly so reliable, 

 as Professor Hilgard pointed out many years ago, on account of the 

 difficulty of wetting the buds of many varieties, owing to their protect- 

 ive covering of woolly hairs. 



