20 CHESTNUT TREE BLIGHT. 
The writers regard $25,000,000 as a conservative estimate of the 
financial loss from this disease up to 1911. In many localities the 
greatest damage has been aaa chestnuts grown for ornamental 
urposes, which have a value greatly in excess of their value as lumber. 
epression in the value of real estate, especially suburban or near- 
suburban, owing to the death of the chestnut trees, must be taken 
into account in an estimate of this kind, as well as the loss of the 
trees themselves. 
: \ iat, 2: Os adh 
| ee > e 
AN 
Fic. 2.—Map of the northeastern part of the United States, showing the distribution of the chestnut bark 
- disease. The horizontally line oe shows the approximate area wherein the majority of chestnut trees 
are already dead from the bark disease. The part marked by vertical lines shows the approximate area 
wherein infection is already complete. The round dots show the location of advance infections of the 
disease. Many of these have already been eradicated. The map has been compiled from both observa- 
tions and eee The writers are under especial obligations to Dr. Poe aes Prof. A. 
H. Graves, Mr. I. C. Williams, Mr. W. H. Rankin, Mr. J. F. O’Byrne, Mr. F. W. Besley, Dr. Ernest 8. 
Reynolds. and Mr. H. G. MacMillan, for data along this line. According to Dr. G. P. Clinton (Connect- 
icut Agricultural Experiment Station, Report of the Botanist, 1909 and 1910) there are many more 
points of infection in Connecticut than are shown on this map. 
CAUSE AND SYMPTOMS. 
The chestnut bark disease is caused by a fungus parasite known 
under the technical name of Diaporthe parasitica Murrill. When 
any of the microscopic spores (reproductive cells) of this fungus gain 
entrance into any part of the trunk or limbs of a chestnut tree they 
give rise to a spreading ‘‘sore”’ or lesion, which soon girdles the tree. 
If the part attacked happens to be the trunk, the whole tree in con- 
sequence is killed, perhaps in a single season. If the smaller branches 
are attacked, only those branches are killed, or only those portions of 
