POTATO FAILURES. 
17 
In Plot No. III. poor seed was selected which was treat¬ 
ed with corrosive sublimate. That only three-fourths of a 
stand was secured was undoubtedly due to weak seed. The 
slight gain over the untreated seed indicated that in any 
method of treatment, it will pay to carefully select the seed 
potatoes. 
The seed potatoes used in Plot No. IV. were of the 
same quality as those used in Nos. 1 and 2, and were treat¬ 
ed with corrosive sublimate. The plants were sprayed four 
times. The results show a gain of 40 per cent over the un¬ 
treated seed in Plot No. II. 
The difference in the average weight of sacks of pota¬ 
toes of the same size from different plots is interesting; the 
potatoes from Plot No. 4 averaging 12 pounds more to the 
sack than those grown in check Plot No. II. No explana¬ 
tion for this difference is offered at this time. 
These experiments show that early blight can be held 
in check with Bordeaux mixture if the spraying is com¬ 
menced early, and done thoroughly, but it is probably a 
waste of time and material to spray plants badly infected 
with Rhizoctonia. 
FUTURE INVESTIGATIONS. 
Different varieties of potatoes vary considerably in their 
susceptibility to disease when grown under the same condi¬ 
tions. It has been observed frequently that of plants of 
different varieties grown in the same hill, and probably 
equally exposed to infection, some will die early in the sea¬ 
son, and produce no tubers at all, while the others will live 
to the end of the summer and produce a fair yield. Even 
plants of the same variety often show considerable differ¬ 
ence in power of resisting the disease. The cause of such 
resistance will be studied, and it is hoped that in time a 
number of hardy or disease resistant varieties may be pro¬ 
duced. 
The best method of treating and wintering the seed is 
receiving careful attention, and it is believed that bin and 
sack infections can be largely prevented. 
Some sections seem to have much trouble with the run¬ 
ning out of potatoes. The indications are that this condi¬ 
tion may be overcome, in some cases at least, but it will be 
necessary to repeat the experiments another year before 
making a report. 
Field observations indicate that Rhizoctonia frequently 
produces a rot of potato tubers. However, only two tu¬ 
bers out of more than one-hundred inoculated in the labora¬ 
tory gave marked results, but many were slightly decayed. 
