Sept.. Ji'idO T. nEMMI.—DII<>BACK DISEASE OF PAULOWMA. 



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tributcd in the northern i)rovinccs of Honshu as well as in the 

 main Island of Hokkaido. 



Symptoms of the Disease. 



This disease attaeks the branches and trunks of Paulownia 

 tomentosa without any regard as to its age. But the young trees 

 of three or four years old are most liable to be attacked. In 

 the case of a young tree, the disease appears first at the tip of 

 the clear trunk in the early spring. The bark of the affected 



part turns brown in colour, 

 as if it was killed b}' freez- 

 ing. The discoloured por- 

 tion gradualK' increases its 

 area, extending downward 

 toward the thicker portion 

 of the stem. From May to 

 June, the disease progresses 

 most rapid!}', and in con- 

 sequence the tree is killed 

 with an appearance of the 

 (lie-back (Fig. 1). On the 

 hark of the dead stem the 

 iiuiting pustules of Valsa 

 break out rather scattering- 

 ly all over its surface (Fig. 

 -) with the exception of its 

 Lip for the extent of about 

 one foot. The fruiting pus- 

 1 ules are at first covered by 

 lIic periderm, which becomes 

 lifted up and finall}' rup- 

 tured, exposing the black 

 stromata of the fungus. 

 Such stromata arc com- 

 "^^^^ paratively small in size and 

 1, i,r. i. contain the pycnidia of the 



1 



