FUNGOUS AND PHYSIOLOGICAL DISEASES. 



471 



tunately it has not made its way into the California dis- 

 tricts, at present the most important in America. 



While the 

 sour orange 

 is very bad- 

 ly affected 

 by scab, lit- 

 tle notice is 

 taken of the 

 disease on 

 that host, as 

 it is used 

 principally 

 as a stock 

 on which to 

 work other 

 varie ties, 

 and is usu- 



lllv Mit off Fig- - " Scab on young- fruit and leaves of Satsuma. 



when a year or two old. It is, however, a drawback in 

 the production of healthy, vigorous stock. But it is with 

 the injury done to the fruit of the lemon that we are most 

 concerned from an economic standpoint. Lemons, to 

 sell well, must be perfectly bright, clean and smooth, 

 and when they are badly affected by this disease, they are 

 rendered unsalable. A rough, distorted fruit finds no 

 place in our markets. 



The scabby leaves, twigs and fruit are very charac- 

 teristically marked. Warty, corky elevations cover the 

 surface, giving to it an unsightly, roughened appearance. 

 Often the leaves are twisted or drawn out of shape, and 

 they are in a considerable degree deprived of the power 

 to fulfill their natural functions, namely: respiration, 



