142 



Diseases of Economic Plaiits 



ored. A considerable portion of the "June-drop" is caused 

 by this disease. 



The spores of the fungus gain entrance through sHght 

 imperfections of the skin at the navel end, producing de- 

 cayed areas under the skin. 



All diseased fruit should be collected and burned or buried 

 deeply. 



Scab {Cladosporium citri Mass.). — Scab has been known 



Fig. 74. — Scab of the sour orange. After Hume. 



for twenty years, and occurs on the sour citrus fruits, such 

 as the pomelo, kumquat, and soin- orange. 



The disease attacks the young leaves, twigs, and fruit, 

 and causes them to produce conspicuous, warty, corky 

 growths, that give a rough, uninviting appearance. Often 

 the leaves are twisted and drawn out of shape. The warts 



