FUNGOUS AND PHYSIOLOGICAL DISEASES. 



467 



Though the tree still continues to bear fruit, its ap- 

 pearance is far from healthy; the leaves become yellow, 



the twigs and young ^ 



branches die, and 

 the whole tree as- 

 sumes an unthrifty 

 appearance. Where 

 the affected tree can 

 be seen from a dis- 

 tance, it stands out 

 in marked contrast 

 to its neighbors. Un- 

 less the disease is 

 checked in someway, 

 the tree attacked 

 eventually succumbs 

 and has to be re- 

 moved. 



Fortunately, all 

 varieties of citrus 

 stock are not in the 

 same degree subject 

 to this dreaded dis- 

 ease. In order of 

 foot-rot resistance 

 they stand about 

 as follows : Sour 

 orange, Citrus Mga- 

 radia; rough lemon, 

 C. Limonum; trifoliate orange, C. trifoliata; pomelo, C. 

 decumana; lemon, C. Limonum; sweet orange, C. auran- 

 tium. Roughly, we may class the first four as decidedly 

 resistant, the last two as very much subject to the disease. 



Fig. 98. 



Foot-rot on crown roots and trunk 

 of sweet c range. 



