214 
Journal of Agricultural Research 
Vol. VII, No. s 
be generally distributed in northern and central Europe and the British 
Isles and was present in northeastern Canada and northern Maine, the 
writers, in cooperation with the Federal Horticultural Board and various 
State agencies, have extended the survey and as a result have found that 
the disease exists in isolated sections from the Atlantic to the Pacific. 
Table I gives its distribution in the United States. 
Table; I .—Present distribution of powdery-scab in the United States 
First collection. 
Collector. 
Infected area. 
Crop 
season. 
Date. 
Location. 
June 23,1913 
Presque Isle, Me.... 
Oct. 24,1914 
Chateaugay, N. Y.. 
Apr. 26,1915 
Nehalem, Oreg. 
May 1,1915 
Hastings, Fla. 
July 23,1915 
Snohomish, Wash... 
Sept. 18,1915 
Virginia, Minn. 
I. E. Melhus 
_do. 
F. D. Bailey... 
I. E. Melhus... 
F. D. Heald... 
C. N. Frey. 
E. C. Stakman 
( Aroostook Comity 
Washington Coun¬ 
ty. 
Penobscot County 
f Franklin Comity. 
\Clinton County... 
f Clatsop County... 
\Tillamook County 
St. Johns County 
Snohomish Coun¬ 
ty. 
Carlton County... 
Lake County. 
St Louis County.. 
1912 
I 9 I 4 
1914 
1915 
19 1 4 
1915 
As shown by Table I, there are six infested sections in the United 
States, all northern, except the one in Florida. This distribution is 
strikingly similar to that of Phytophthora infestans and lies wholly within 
its geographical range, which is confined to the northern part of the 
United States and to certain sections of the South in which a potato 
crop is grown during the winter. 
distribution as determined by infected seed in various 
localities 
In order to determine whether Spongospora subterranea would develop 
south of infected sections in Maine and New York, infected seed was 
planted in 12 different States along the Atlantic seaboard in the spring 
of 1915, trials being made at more than one point in some States. 
The experiment was carried on in cooperation with the State pathologists 
and others interested in potato diseases, and the seed was planted in 
each case in accordance with the general practice in the respective lo¬ 
cality. The results obtained are summarized in Table II. 
As shown by Table II, no powdery-scab developed in any of these 
experiments. In each case all of the suspicious-looking specimens were 
sent to the writers for examination. 
