562 Journal of the Department of Agriculture. 



The Stock. — It is well known that certain stocks are, speaking 

 o-enerally, more vigorous growers than others (e.g. Mourvedre x 

 Rnpestris 1202). It is also acknowledged that on the inherent 

 characteristics of the stock v.'ill depend whether it will be attacked 

 by phylloxera or not. (A similar occurrence which we find in 

 animals, which on entering a vineyard will first devour the leaves 

 and shoots of Hanepoot before they touch any of the other kinds.) 

 Although phylloxera mnj be found on the roots of all types of 

 American stocks (species and varieties), some are only lightly affected 

 while others are completely destroyed. 



If we plant tAvo kinds next to each other in the same soil (let us 

 say in the same receptacle) and then infect their roots with phylloxera, 

 we will find after a while" the roots of the one appreciably affected 

 with phylloxera, while the other will for practical purposes be clean. 

 Tt is of course understood that two varieties would be chosen Avhich 

 differed considerably in their power to resist phylloxera. From this 

 we see that phylloxera will attack one kind of stock more readily than 

 another. Moreover, the wounds caused by phvUoxera are not equally 

 serious to the roots of different lands, and the various types of 

 American stocks do not all possess the same capacity for closing up 

 lliese wounds or of allowing them to heal. Here it must be explained 

 that a stock is not killed because the phylloxera robs it of too much 

 of its sap or because it becomes poisoned, but because certain 

 organisms of decomposition present in the soil are enabled, through 

 fbe Avounds made by the phylloxera, to enter the roots and cause 

 ill em \o decay. 



It will therefore be under-stood that different kinds of stocks will 

 under similar conditions show a varying degree of resistance \o 

 phylloxera. 



Soil. — The soil is of the greatest importance in relation to the 

 growth of the vine as well as the attacks of phylloxera. In well- 

 drained soils of good depth and possessing a fair supply of plant food 

 ingredients (including water) a stock will make good growth. In 

 light, shallow soils, which are usually too wet in winter and too dry 

 during the summer, one cannot expect it to make satisfactory 

 progress. Where the foregoing statement applies we find that 

 American stocks exhibit great differences in their growth on different 

 soils. We can understand then that the soil is one of the most 

 important factors which we have to consider in making a choice of a 

 suitable stock. 



That the soil exercises a greai influence on the attacks of 

 ])hylloxera is evidenced by the fact th;it phylloxera destroys European 

 vines much sooner in clay soil than in sandy soil, while in a deep 

 fine sandy soil it either fails to destroy or infests only slightly. This 

 is the reason why the coastal portion of France, bordering on the 

 Mediterranean Sea, has been established on European stocks. In 

 this area we find deep, fine sandy soils in which phylloxera has an 

 almost negligible effect. In our own country there still exists old 

 ungrafted vineyards, established on deep, line sandy soils, which are 

 deteriorating at a very slow rate. By a sound system of fertilizing, 

 lliis deterioration may still further be I'elarded, and instances are 

 known of old ungrafted vinevards which, bv good manuring with 



