PART II. 
DETAIL OF EXPERIMENTS, 
Experiment I. —During the winter of 1900, Mr. J. G. Coy of Fort Collins, 
called our attention to the peculiar shape of the potato tubers grown on 
his place during the previous summer, apparently a mixture of Rose Seed¬ 
ling and Queen of the Valley. Many of the tubers were long and pointed, a 
good lot of what growers call “run out seed.” 
In the spring of 1901, seed was carefully selected from the No. 2’s of 
the above lot, all diseased and “run out” tubers were rejected, and the seed 
was treated with corrosive sublimate. 
The plants came up nicely but most of them blighted badly and were 
killed two weeks before frost. The field yielded 150 sacks of tubers per 
acre, and the tubers were much better than those harvested in 1900. Nine 
hundred and eighty pounds of the No. 2’s of this crop were used as seed in 
the experiments of 1902. All tubers were carefully sorted and washed. The 
diseased and badly “run out” tubers were placed in the poor lot and are 
known as cull seed. There were 254 pounds of poor and 796 pounds of good 
seed. All the culls and 434 pounds of the better seed were treated with a 
solution of 8 oz. of formalin to 15 gallons of water. 
The field selected for these experiments is located on the river bottom 
just east of town, the soil is of a black sandy loam. The field was plowed 
in early spring, and the seed was planted on April 25th. The rows were 
placed 36 inches apart and the pieces were placed at intervals of about 15 
inches in the row and 4 inches deep. 
The plants came up uniformly, and those of Plats IV and VI were 
sprayed five times. The ground was kept in almost perfect condition and 
the plants looked unusually promising until about July 27th, when the field 
was thoroughly water. From this time on the soil was compact and soggy, 
making the condition favorable for the development of Corticium. The roots 
of many of the plants were killed. The leaves and stems soon showed 
marked signs of sun scald. These injuries were soon followed by an attack 
of Altenaria, which resulted in the complete destruction of all the unsprayed 
plants by August 18th. The sprayed plants fared a little better, but they, 
too, were severely injured and were all dead and dry by August 25th. There 
were very few, if any, pointed tubers found in selected seed lots. In this 
experiment a sack of potatoes is estimated at 100 pounds. 
Plat I Check —The seed of this lot was sorted with the greatest care. 
All diseased and injured tubers were rejected. Those which were long and 
pointed, or showed signs of “running out” were also rejected. The ground 
was quite dry at planting time, yet the plants were not long delayed in 
reaching the surface of the ground. This lot gave a yield of 212 sacks per 
acre. No “run out” tubers were observed in this plat at harvest time. 
Plat II —The seed in this experiment was selected with the same care 
as that of the preceding plat. But it was treated in a solution of formalin 
on April 18th and planted on April 23rd. These plants reached the surface 
of the ground on time. This plat occupied the lowest part of the field; con¬ 
sequently the subterranean parts of these plants suffered more from the in¬ 
vasion of Corticium than those of the preceding plat. These plants were also 
the first to blight. This plat gave a return of 185 sacks per acre, making a 
yield of 26 pounds of tubers for every pound of seed planted,—a loss of 12%. 
No “run out” tubers were found in this plat at digging time. 
Plat III —The culls taken from the two preceding lots were used in this 
plat. It was treated in a solution of formalin on April 18th and planted on 
April 23rd. The plat was also located on low ground, and these plants were 
the first to blight. An average yield of 130 sacks per acre was obtained from 
this plat—18 pounds of tubers for every pound of seed tubers planted—a loss 
of 39%. Many long and pointed tubers were taken from this plat. 
