Oct. 3 o, 1916 Spongospora subterranea and Phoma tuberosa 
215 
Table II .—Results of planting seed infected with Spongospora subterranea outside the 
infected area 
Locality. 
Grower. 
Number 
of hills. 
Result. 
Arlington, Va. 
Bureau of Plant In- 
2,944 
No powdery-scab. 
dustry. 
West Raleigh, N. C. 
H. R. Fulton. 
80 
Do. 
New Brunswick, N. J. 
M. T. Cook. 
2A2 
Do. 
College Park, Md... 
J. B. S. Norton. 
IOO 
Do. 
Gainesville, Fla.. 
H. E. Stevens. 
IOO 
Do. 
Ithaca, N. Y.. 
M. F. Barrus. 
72 
Do. 
East Marion, N. Y. 
F. V. Rand. 
48 
Do. 
Geneva, N. Y. 
F. C. Stewart . 
SO 
Do. 
Newark, Del. 
T. F. Manns. 
6O 
Do. 
Arrfherst } Mpss.. 
A. V. Osmun. 
l8 
Do. 
Norfolk, Va . 
T. C. Johnson. 
200 
Do. 
Clemson College, S. C . 
H. W.'Barre. 
IOO 
Do. 
New Haven, Conn . 
G. P. Clinton. 
460 
Do. 
State College, Pa. . . 
C. R. Orton. 
200 
Do. 
Morgantown, W. Va. 
N. J. Giddings. 
8l 
Do. 
As the season of 1915 was especially wet and still no Spongospora sub¬ 
terranea developed in any of the various localities named, it seems safe 
to assume that its chances for development in seasons with normal 
rainfall would be still more Unfavorable. 
Each of the trials referred to was on a small scale and for one season 
only, except that at Arlington, Va., which was carried through two 
seasons. In this trial 13 rows were planted in 1914 and 10 in 1915, or 
in all about 2,944 kills, with infected seed, and also, in 1915, 3 rows, or 
384 hills, with clean seed in soil which had been planted with infected 
seed in 1914. In none of these rows was a single tuber found to be 
infected with Spongospora subterranea; consequently it seemed safe to 
assume that the conditions were not favorable to the disease, and this 
raised the question as to what constitutes the limiting conditions. 
distribution as determined by transplanting soil from other 
STATES INTO NORTHERN MAINE 
The influence of climate was studied by obtaining 200-pound lots of 
soil from 12 of the plots that had been planted with infected seed in 
nine of the States mentioned in Table II, shipping it to northern Maine, 
and planting it with infected seed of the Irish Cobbler variety. Naturally 
these soils varied materially in texture and composition, some being 
extremely light, while others were very heavy. These samples were 
placed in boxes 2 feet square and 8 inches deep, and the boxes set down 
into the soil in a field of virgin land where conditions were favorable for 
the development of Spongospora subterranea. 
Because of *the late arrival of most of the soils, planting was later 
than is usual in this section—that is, on June 19 in eight cases and on 
