84 Scientific Proceedings, Royal Dublin Society. 



this kind, suitable inoculation experiments with potato plants would enable a 

 definite decision to be made. 



VIII. Relation of the Veeticillium Disease to " Cukl " and 



" Leaf Roll." 



The term " Curl " has long been in use for certain potato troubles. A 

 disease known by this name is said to have been seen first in England so 

 long ago as 1764 ; and towards the end of the eighteenth and during the 

 early part of the nineteenth centuries it was the subject of much discussion 

 by agricultural writers of the day. The literature on the subject is very 

 extensive, but, unfortunately, in the main it is most unprofitable reading. 

 From a study of this literature it is impossible to obtain an accurate idea 

 of what the Curl really was, for most of the writers on the subject preferred 

 exercising their imaginations in speculations as to the probable causes of the 

 disease and in formulating remedies for it, rather than attempting to give a 

 careful description of the symptoms which characterized it. It is quite 

 possible, and indeed probable, that the term " Curl " was applied to more than 

 one distinct disease of the potato ; and this supposition, if correct, would 

 serve to explain the conflicting opinions often published concerning it. 

 Anyone who wishes to get an insight into the complexity of the views 

 concerning "Curl" which prevailed during the early part of last century 

 cannot do better than consult such a summary of them as that published 

 in 1804 by Forsyth. 1 



Apparently as time went on the trouble known as " Curl " became less 

 serious, and in the middle of the nineteenth century it was for a time quite 

 overshadowed in importance by the epidemics of blight from which the 

 potato crop then suffered. Nevertheless, it is clear from HallierV account 

 that the disease (Krauselkrankheit) was still prevalent in the early seventies 

 of last century in many districts in Germany. Hallier's description of it 

 would lead one to believe that it was one caused by a specific fungus 

 inhabiting the vessels of the wood, and perhaps identical with the Verticillium 

 disease described in the present paper. He himself certainly adopted this 

 view, and named the supposed fungus Bhizoctonia tabifica. It is clear, 

 however, that Hallier applied this name not to a single fungus, but to more 



1 "The Principles and Practice of Agriculture," systematically explained, in two 

 volumes ; being a treatise compiled for the fourth edition of the Encyclopaedia 

 Britannica, and revised and enlarged by Robert Forsyth, Esq. Edinburgh: Constable & 

 Co., 1804. See particularly p. 174 et seq. 



2 Hallier, E., "Die Ursache der Krauselkrankheit." Zeitsch. f. Parasitenkunde, iv, 

 1875, p. 97. 



