272 FIFTEENTH ANNUAL REPORT OF THE 



In Europe, according to Prof. Sommerville, the disease is so much on 

 the increase that the outlook in that country for our white pine and other 

 five-needed American pines is almost hopeless. There are estates in England 

 where hardly a living young white pine is left. In Denmark and in some 

 places in Russia, as near Moscow, for instance, the raising of white pine had 

 to be entirely given up on account of this rust. The same is true of Holland 

 and portions of Germany. Other European countries are affected. 



The seriousness of the disease must not be underestimated. The value 

 of white pine from a forestry standpoint is too great for us to allow its future 

 to be threatened in any way. It would be far better to delay a part of our 

 reforesting until American nurseries can be established which will produce 

 the necessary planting stock. 



The people of this State have no cause for alarm because every known 

 plantation made with German white pine in this State has been carefully 

 examined, the Ribes destroyed and the inspection will be continued the 

 coming spring. We can further say that every effort will be made by us 

 to prevent importations of pine. The disease is well under control and our 

 only trouble will be to prevent nurserymen and private parties from im- 

 porting. 



The accompanying colored plate shows the appearance of the disease 

 and an explanation follows: 



Plate 1. A live, young white pine plant showing swelling of the 

 trunk and of the branches at the whorl, and on these swollen parts the yellow 

 spore bags (Aecidia) of the Peridermium Strobi. 



Plate 2 . Branch of the white pine showing the swelling caused by the 

 blister rust. The entire swollen part and the branches starting from it 

 are already dead. The bark is torn. The Aecidia of last year have dropped 

 off. 



Plate 3. Currant leaf with Cronartium ribicolum on the under side. 

 The bright yellow deposits are the Uredospores, which spread from Ribes 

 to Ribes; the brownish strings are the Teleutosspores, whose Sporidia again 

 transmit the disease to the white pine and there produce the Peridermium 

 Strobi. 



