ORA^^GE RUST OF BLACKBERRIES 



101 



The most extended account of this disease is pub- 

 lished in the 1887 Report of the Department of Agri- 

 culture (pp. 35T-361). 



The Orange Rust 



Cceoma nit ens 



The orange rust, or red rust, of blackberries, is fa- 

 miliar to most growers of small fruits. The disease 

 becomes noticeable as soon as the foliage expands in 



a b 



FIG. 47. ORAXGE RUST. 



ff, Under surface of blacklierry leaf sliowiiiGr spots of pecidium stage; 5. same of 

 raspberry leaf sliowiiig iDotli Eecidium and Piicclnia spots. 



spring, affected leaves having a peculiar golden color, 

 which at once distinguishes them. A little later the 

 surface becomes more or less covered with small round 

 patches of orange-colored spores, to Trhich the common 

 name is due. The life-history of the fungus has only 

 recently been definitely worked out. 



The fungus exists on the blackberry plant in two 

 very different stages. The orange spores that are devel- 

 oped in spring and early summer, as shown in Fig. 48, 

 belong to the CEcicliiim stage. They germinate on the 



