Pethybridge and Lafeerty — Dry-Rot of the Potato Tuber. 211 



for the purpose and the same stock used throughout the trials. In addition 

 to one of our own strains of F. ccerideum we also used the one obtained from 

 Amsterdam for inoculating purposes, this being done through wounds as 

 already described for other such experiments. Controls were of course used 

 in all cases, and in every instance they remained sound. 



The table clearly shows that there is a progressive susceptibility to rot, 

 the maximum being reached early in the new year. This fact probably 

 explains why it is that complaints of serious losses due to dry-rot are not 

 made as a rule until some months after storage has begun. 



The cause of the increased susceptibility is perhaps to be looked for in 

 some change in the chemical composition of the contents of cells of the 

 tuber, and with this in view, an attempt was made to increase the suscepti- 

 bility to decay in autumn by keeping the tubers for some twenty hours or so 

 in a vessel surrounded with a mixture of ice and salt before inoculation. 

 This treatment was so arranged as not to be severe enough to kill the tubers 

 by freezing, and they sprouted quite normally subsequently. It was found, 

 however, that the tubers were not thus rendered more susceptible to 

 infection. Two experiments of this kind were carried out, and when the 



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