284 Diseases of Truck Crops 



itself a parasite, is in turn parasitized by three other 

 fungi. 



1. Darltica fUum Cast. This fungus develops on 

 the rust pusttiles, living directly on the mycelium 

 and spores of its host. 



2. Tubercularia persicina DUt. 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 abtmdant and of 

 economic importance. 



Damping Off, see Rhizoctonia, p. 45. 



DISEASES OF THE CHIVE {Allium schoenopo- 

 rasum) 



Rust 



Caused by Puccinia porri (Sow.) Wint. 



This rust, though prevalent in Europe, has been 

 reported but once in the United States by Clinton' 

 as attackin g also onions. It is characterized by a yel- 

 lowing of the leaves which die prematurely. On care- 

 fully examiniag the infected leaves we find the viredo 

 pustules, which are minute, reddish, and covered with 

 a reddish powder. The teleuto pustules are black and 



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

 726. 



