New Yokk Agricultural Experiment Station. 207 



against 67.1 bushels per acre on the check rows. One un- 

 familiar with the experiment might draw the conclusion that 

 lime-sulphur has some value as a preventive of tuber rot. How- 

 ever, the facts in the case do not warrant such a conclusion. The 

 correct interpretation seems to be as follows : There was less 

 tuber rot on the lime-sulphur rows because at the time blight 

 attacked the field there were fewer live plants on these rows. 

 Many w^ere already dead and incapable of taking blight, conse- 

 quently they were incapable of transmitting the disease to the 

 tubers. On the check rows there were more living plants for the 

 disease to attack. Such plants as were still alive on the lime-sul- 

 phur rows seemed to be quite as severely attacked as those on 

 check rows, but the data on this point are insufficient for definite 

 conclusions. 



It is also worthy of note that all the rotten tubers on the 

 bordeaux rows were found in a slight depression at the north end 

 of the field, where the surface water from rains flowed across 

 the rows and undoubtedly carried spores from the adjoining in- 

 fected rows. No blight was found upon plants in the bordeaux 

 rows at any time during the season. 



There was a marked difference in the size of the tubers from 

 the rows under different kinds of treatment. Tubers from the 

 bordeaux rows were somewhat larger than those from the check 

 rows and considerably larger than those from the lime-sulphur 

 rows. 



It is not strange that the lime-sulphur rows gave a lower yield 

 than the check rows when one considers the dwarfed condition 

 of the plants in those rows and the fact that a great many of 

 the plants were dead several days before those in the check rows. 



Although blight did not appear until late in the season after a 

 large percentage of the plants had died, so that the amount of 

 foliage affected was not large, the severity of the tuber rot is sur- 

 prising. It is evident that under favorable weather conditions a 

 small amount of blight may cause a heavy loss from tuber rot. 



