POTATO FAILURES. I 5 
der to obtain good results the treated seed must be planted in 
soil which is free from the disease. 
Field Experiments. Encouraged by the promising re¬ 
sults in the greenhouse experiments, although somewhat 
late in the season, we concluded to try the treatment on a 
larger scale. Accordingly arrangements were made with 
Mr. J. G. Coy of Fort Collins, to carry on an experiment on 
his farm, in which he kindly consented to assist us. The 
soil of the field selected for the experiment was of heavy 
black loam on the river bottom. It was afterwards found 
that the level of the soil water was comparatively close to 
the surface. It had been flooded by late rains, and was 
too wet to get in shape for planting before June 6th. Most 
of the ground had been planted alternately with cabbage 
and onions during the past five years. It is quite probable 
that the soil contained more or less of the fungus since 
onions which remained in the field from last year’s crop 
were badly infected. Potatoes grown on this place have 
suffered more or less from early blight for a number of 
years. 
This field was divided into four plots. The rows were 
twelve rods long and planted in the usual way. All four plots 
were planted with Wisconsin seed of the Pearl variety. 
These tubers were infested with Rhizoctonia. Plots I., III. 
and IV. were sprayed with Bordeaux mixture, and Paris 
green on July 7th, 17th, 31st and August 15th. The seed of 
Plots III. and IV. was treated with corrosive sublimate as 
given on page 12. The seed of Plots I. and II. was not 
treated. The rains during the fore part of the season kept 
the ground sufficiently moist for the growth of the plants 
and the field received its first irrigation on August 13th. 
From this time on the ground was kept quite moist. T he 
potatoes were dug October 10th. 
Plot I. This plot occupied the lowest and most poorly drained 
part of the field. The seed of this lot was not treated, but the plants 
came up nicely, and most of them looked promising during the early 
part of the season. They were sprayed thoroughly four times, and re¬ 
mained green until killed by frost. Joining this plot was a garden 
patch of potatoes which was badly infected with the Rhizoctonia. 
The leaves of these diseased plants soon took on a lighter green color, 
had a tendency to fold, the stems became heavier, their internodes re¬ 
mained short," and in many of the plants, grew prostrate. These tops 
were soon invaded and completely ruined by early blight. During the 
later part of July, it was observed that a number of the plants in the 
rows joining the garden patch were taking on an abnormal top develop¬ 
ment. After the first watering, this peculiarity became prominent on 
many other plants, and at the close of the season, it is doubtful if there 
was a single plant in the entire plot which had a normally developed 
top. On August 10th, a careful examination was made of fifty plants 
taken from various parts of this plot, and it was found that the hyphae 
of Rhizoctonia occurred most abundantly on the plants in the first three 
