14 BULLETIN 70. 
planting is delayed, the cut pieces should be placed in a 
moist, cool place. 
EXPERIMENTS IN TREATING SEED POTATOES. 
Greenhouse Experiments. The following experiments 
were conducted in the greenhouse to get some hints on the 
value of treating infected tubers with corrosive sublimate: 
Experiment 1. The first experiment was with sixteen pots filled 
with sandy, clayey soil which was thoroughly infected with the disease. 
The soil in eight of these pots was sterilized two hours a day for three 
consecutive days, and planted with apparently healthy seed which had 
been placed in a solution of one ounce of corrosive sublimate to eight 
gallons of water for one and one-half hours. All tubers produced 
healthy and quite vigorous plants which lived until the experiment was 
closed. Careful examinations showed that all but one of these plants 
were free from disease. This infection was probably due to careless¬ 
ness in watering the plants with a hose, since pots containing treated 
and untreated soils stood side by side. The soil in the other eight pots 
was not sterilized, and planted with clean tubers, treated in the same 
manner as those in the first lot. The potatoes all grew, but the plants 
did not do so well as those in the first lot, and three of them died shortly 
before the experiment was closed. On examination, it was found that 
all the plants were infected with the disease. A number of sclerotia 
were found on four of the tubers. 
Experiment II. The second experiment contained twelve pots of 
heavy black loam which had been used in growing Alternanthera in the 
greenhouse during the preceding winter. The soil in the first four pots 
was not sterilized and was planted with tubers on which there were 
numerous sclerotia. These tubers were treated with One ounce of cor¬ 
rosive sublimate to eight gallons of water for one and one-half hours. 
The plants did quite well, but careful examination showed that all were 
more or less affected with the disease. The soil in the next four pots 
was sterilized two hours a day for three consecutive days, and planted 
with seed treated in the same way as those in the preceding lot. These 
plants made good growth and lived until the experiment closed. Crit¬ 
ical examination failed to reveal any traces of the disease. The soil in 
the last four pots was treated as in the second lot, but was planted with 
infected tubers. One tuber failed to grow. Two produced weak plants 
which died prematurely and the fourth plant did poorly, but lived until 
the experiment closed. All plants were infected with Rhizoctonia. 
Experiment III. In the third experiment, thirty diseased tubers 
were planted in a bench containing three inches of potting sand on the 
bottom and four inches of sandy clay loam on top. The first lot con¬ 
tained fifteen tubers which were treated with one ounce of corrosive 
sublimate to eight gallons of water for one and one-half hours, and 
planted twelve inches apart. These plants were slow in reaching the 
surface of the ground, but otherwise, they did nicely, and remained 
green until the close of the experiment. Thirteen of these hills, con¬ 
taining fifty-seven plants, were free from the disease, and only one 
plant in each of the other two hills, containing eight plants, was in¬ 
fected. It is possible that this was due to soil infection. In the second 
lot used in this experiment, the tubers were not treated, otherwise the 
conditions were much the same as in the preceding. Some of the 
plants soon reached the surface of the ground; others, however, were 
considerably delayed, and a number were killed before reaching the sur¬ 
face. Those which finally became established did quite well apparently, 
but twelve of the hills, sixty plants, died two weeks before the experi¬ 
ment was closed, and all were covered with an abundance of Rhizoctonia 
hyphae. The other three hills, fifteen plants, lived, but a careful examina¬ 
tion showed that all of them were more or less affected with the disease. 
These experiments show that diseased potatoes may be 
readily disinfected with the corrosive sublimate. But in or- 
