LETTER OF TRANSMITTAL. 
U.S. DEPARTMENT OF AGRICULTURE, 
BUREAU OF PLANT INDUSTRY, 
OFFICE OF THE CHIEF, 
Washington, D. C., April 15, 1910. 
Str: [I have the honor to transmit herewith a manuscript entitled 
“Wield Studies of Crown-Gall and Hairy-Root of the Apple Tree,”’ 
by Dr. George G. Hedgecock, at present Pathologist in Investigations 
in Forest Pathology. 
This paper embodies the results of several years of ceetientan 
and experiment and covers the distribution of crown-gal! and hairy- 
root, a description of their different forms, their probable relations, 
and their development; the effect of the diseases upon apple trees; 
the susceptibility of varieties; communicability in the nursery and 
orchard; and prevention and cure. The paper marks the comple- 
tion of Doctor Hedgcock’s work on this subject. The field study 
of these diseases will be continued by the Office of Fruit-Disease 
Investigations. 
Studies of the etiology and interrelations of crown-gall have been 
made by Messrs. Smith and Townsend and by Miss Brown, of the 
Bureau of Plant Industry, and are still in progress. 
I respectfully recommend that this manuscript be published as 
Bulletin No. 186 of the series of this Bureau. 
Respectfully, ear 
a GATE LO WAN: 
Chief of Bureau. 
Hon. JAMES WILSON, 
Secretary of Agriculture. 
Go 
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