130 A MANUAL OK FORESTRY 



and Canada, while diseased pines have been found in New 

 Jersey, Pennsylvania and Ohio. 1 



In Europe this species of Peridermium has long been common 

 on Finns ccnibra, or stone pine, which is the European variety 

 of white pine. Of late years with the multiplication of planta- 

 tions of our American species throughout Europe the disease 

 has attacked these. In some regions it has caused much havoc, 

 especially in nurseries. In certain places, notably, in Holland; 

 at Oldenburg, Germany; and at Moscow, Russia; the disease 

 is so serious that the cultivation of white pine has been aban- 

 doned. Young trees are killed outright by the disease, and the 

 small branches of large trees are killed. 



The affected seedlings have a peculiarly stunted appearance, 

 and the stem is abnormally enlarged and swollen in places. 

 New growth is very short. The orange fruiting bodies on the 

 stem, which, however, occur only in the spring, furnish the best 

 means of identification. 



This fungus is one stage of the blister rust of currants and 

 gooseberries known as Cronatium rubicola. In other words, 

 like the wheat rust, cedar apple, and many similar fungi, it is 

 a fungus which requires two hosts to complete its life history. 

 The spores from an infested currant or gooseberry bush are 

 blown to a neighboring white pine tree. Here they germinate 

 and the mycelium vegetates in the inner bark until the second 

 spring after infection. Then the diseased bark thickens and 

 the stem becomes swollen. The fruiting bodies break through 

 the bark sometime between the middle of April and June, 

 according to the locality and the season. They are of a light, 

 orange color and project from the stem about one-eighth of an 

 inch. They soon break open and the spores are scattered by 

 the wind. After the spores are gone, the remains of the fruit- 

 ing bodies are washed off, leaving empty fissures in the bark to 

 show where they were. The spores from the pine, if they 

 chance to fall upon currant leaves, infect them in turn. On 



1 Sec Hull. 1 5, Conservation Commission, State of New York, "The Pine 

 Blister," by B. H. Paul, State I orrster. 



