284 Diseases of Truck Crops 



itself a parasite, is in turn parasitized by three other 

 fungi. 



1. Darluca filum Cast. This fungus develops on 

 the rust pustules, living directly on the mycelium 

 and spores of its host. 



2. Tubercularia persicina Dilt. This fungus is 

 not as common as the first one. 



3. Cladosporium sp. This is a common fungus 

 which is often abundantly found on rust pustules. 

 All or any of these three natural enemies may be 

 readily grown in pure culture and spread about 

 broadcast wherever the rust is abundant and of 

 economic importance. 



DAMPING OFF, see RHIZOCTONIA, p. 45. 



DISEASES OF THE CHIVE (Allium schoenopo- 

 rasum) 



RUST 



Caused by Pucdnia porri (Sow.) Wint. 



This rust, though prevalent in Europe, has been 

 reported but once in the United States by Clinton 1 

 as attacking also onions. It is characterized by a yel- 

 lowing of the leaves which die prematurely. On care- 

 fully examining the infected leaves we find the uredo 

 pustules, which are minute, reddish, and covered with 

 a reddish powder. The teleuto pustules are black and 



1 Clinton, G. P., Connecticut Agr. Expt. Sta. Rpts. 1909-1910 : 

 726. 



