THE FOREST NURSERY 361 



blister rust introduced from Europe. This is a disease of the 

 white pine and a number of allied species. Although long known 

 in Europe as one of the most destructive nursery pests, it did not 

 appear in the United States until 1906. l Since then it has been 

 investigated by Stewart, Spaulding, Clinton, and others. Although 

 first recognized in this country in 1906, it is now widely distrib- 

 uted. The uredo stage which occurs on various species of Ribes 

 has been reported from such widely separated localities as Kansas 

 and Vermont. It has been found in a number of localities in 

 Connecticut, Massachusetts, and New York. Spaulding 2 has re- 

 cently reported the disease as infesting the crown of a large white 

 pine in Vermont. As yet it has appeared in forest nurseries in 

 the United States only on stock imported from Europe. It is 

 now, however, so widely distributed that it is believed to be but 

 a matter of time before it will be found infesting nursery stock 

 grown in this country. Its possibilities for causing enormous 

 losses are so great that close watch should be kept in all nurseries 

 that grow white pine and allied species in order to prevent its 

 gaining a foothold. Wild and cultivated species of Ribes in the 

 vicinity of the nursery which harbor the uredo form of the fungus 

 should be destroyed. If the disease appears in the seedbeds or 

 transplant beds, all the stock should be pulled up and destroyed. 

 There is no known method of treatment which will save a young 

 tree when once infected. 



1 Stewart, F. C.: An outbreak of the European currant rust (Cronartium 

 riUcola). (N. Y. Agri. Exp. Sta., Tech. Bui. 2, p. 61. Geneva, 1906.) 



2 Spaulding, Perley: New facts concerning the white pine blister rust. 

 (U. S. Dept. of Agri., Bui. 116, p. 2. 1914.) 



