47 
bright crimson dots. In reality they are ovoid in shape, as cau 
readily be seen with a good hand lens. During the winter they 
can usually be found at the margins of the cankers. In the sum- 
mer season I have found another type of spore (conidia) borne 
on the surface of the diseased tissue. I have found the Nectria 
canker affecting also the Paper Birch and Yellow Birch in Maine. 
Experimental studies (Brooklyn Bot. Gard. Rec. 15: 59. 1926) 
have shown that the same fungus is the malefactor here. There 
is reason to believe that the gray birch is also susceptible. 
No remedies seem to be practicable as far as cankers on the 
trunk are concerned, unless one wishes to subject the tree to the 
rather expensive process of cutting out of the diseased area. Even 
in this case, one could never be certain of removing all of the dis- 
eased wood, and furthermore, an unsightly cavity would be left. 
(We do not subscribe to the practice now in vogue of filling cavi- 
ties with cement, etc.) However, in case small twigs are affected, 
they should be removed as soon as possible, making the cut some 
distance below the affected area, i.e., toward the trunk of the tree. 
The diseased parts should be burned, in order to destroy the 
spores, and the cut ends of the twigs on the tree should be 
promptly painted over with ordinary lead paint to prevent fresh 
infections. 
— 
For owners of woodlands the only practicable measure is to 
remove these diseased trees at the earliest convenient opportunity 
—either during improvement thinnings or during any other cut- 
ting. Thus the fungous spores will be prevented from infecting 
the sound trees, young and old, that otherwise are almost certain, 
sooner or later, to contract the disease. The diseased portions, 
and particularly the bark surrounding them, should be burned. 
To determine the rate of growth of the fungus in the tree and 
also its effect on the timber, as well as other data, inoculations on 
healthy sweet birches on land of the writer in Hamden, Conn., 
were made in 1918 These cankers have grown slowly ever 
since, but beyond inspection of them each year, no further work 
has been done. 
In October, Dr. Perley Spaulding, of the U. S. Department of 
Agriculture, informed the writer that he had observed what was 
apparently the same disease causing much damage to Yellow 
oy) 
