GOOSEBERRY DISEASES 227 



EUROPEAN CURRANT-RUST 

 Caused by Cronartium Ribicola Fisch. von Wald. 



The European currant-rust, or white pine blister-rust, is 

 known to occur on the gooseberry, although it is notably less 

 common on this plant than on the currant. The characteristics 

 of the disease on the gooseberry may be understood by reading 

 the account as presented under Currant, page 212. 



CLUSTER-CUP RUST 



Caused by Puccinia Pringsheimiana Kleb. 



The cluster-cup rust is exceedingly common on wild goose- 

 berries and currants and is known to some extent on cultivated 

 forms. It occurs in Europe, Alaska and in many parts of the 

 United States. Serious damage is seldom reported, although 

 some complaint was made several years ago (1892) of the loss 

 of foliage and fruit on account of an unusual outbreak. 



Symptoms. 



The disease may be recognized in the early summer by the 

 presence of bright, orange-colored cups grouped on reddish, 

 swollen areas on the lower surface of the leaf. Sometimes these 

 structures are found on the fruit, causing distortions. 



Cause. 



The cluster-cup rust fungus is Puccinia Pringsheimiana. The 

 orange-colored cups already described contain spores known 

 as seciospores. These are carried to various common sedges, 

 Carex acuta and C. Goodenovii, where infection takes place. 

 Following the development of the mycelium within the sedge 

 leaves, a second type of spore structure, known as a uredineum, 

 is produced ; the uredinia bear uredospores. Later a third 

 kind of fruiting body appears ; this is known as a telium, and 

 it bears teliospores. In the latter condition the winter is 



