220 HORTICULTURE FOR SCHOOLS 



laterals as B did, previously, and L will develop two shoots 

 as A did in the previous season. 



Next year's pruning will consist in removing M at R and 

 the two canes of L will be treated as are the two canes 

 of A. Thus the process is continued year by year. 



330. Phylloxera. The most destructive insect enemy of 

 the European grape (the American species are immune) is 

 the phylloxera, or root-louse. It was unknown in Europe 

 until about 1855 when it was introduced into France on 

 stock imported from America. At first it manifested itself 

 in a few isolated localities only; but soon spread from vine- 

 yard to vineyard and from section to section, until in the 

 year 1888, injury directly due to it was estimated at two 

 billion dollars. The cause was found to be a very small insect, 

 which can be distinguished only with the aid of a hand-lens, 

 and which burrows into the tissue of the root, causing galls or 

 excrescences which ultimately kill the vine. Many remedies 

 have been tried; but the only one that is successful is that 

 of grafting the desired variety on stock of resistant American 

 forms. American stock imported into France finally re- 

 established the grape industry in that country. 



331. Other insects. A number of other insects cause 

 injury to the grape, among them, the vinehopper, root-worm, 

 grape-beetle, cutworm, grape-curculio, sawfly, root-lover, and 

 grape-vine sphinx. Each has been studied and information 

 concerning methods of control can be found in the publica- 

 tions of the experiment stations. 



332. Raisins have long been used as human food. They 

 are mentioned several times in the Old Testament 1 and other 

 writers, ancient and medieval, bear witness to their popu- 

 larity. Until the development of the raisin industry in Cali- 

 fornia within the last few years, they were produced solely 

 in a few countries about the Mediterranean. California is 

 now forging ahead in the commercial production of raisins. 



i Numbers VI-3; I Samuel XX V-l 8; XXX-12. 



