WART DISEASE OF POTATOS. 



307 



Leinster Wonder (Williamson). 



Linda (Gardiner). 



Majestic (Findlay). 



Nithsdale. 



Paragon. 



Peacemaker (Scarlett) or Golden 



Rose 4. 



Shamrock. 



St. Malo Kidney. 



Supreme (Sutton). 



Templar (Wilson). 



The Laird (Davie). 



The Lochar (Farish). 



Tinwald Perfection (Farish). 



White City (Sutton). 



Wonder (Brown). 

 Rector (Wilson). 

 Rhoderic Dhu (Farish). 



It is interesting to note that experiments in Germany are being 

 tried on similar lines to those carried out in England. The fungicide 

 experiments have given negative results, but the immunity trials have 

 shown that certain German varieties are immune. The latest publica- 

 tion (87) only mentions two varieties as being completely immune, but a 

 number are mentioned as being very slightly susceptible in some of 

 the trials. In all probability disease in such cases was present on 

 rogues as in the early English trials. Such varieties when properly 

 rogued showed no sign of warts. 



Outside Europe, Wart Disease has only been found in the United 

 States of America. It was discovered in September 1918 in three 

 counties in eastern Pennsylvania, while it has since been found in West 

 Virginia (47). It is believed to have been imported from Europe 

 in 1912 with eating potatos of an inferior quality. The United States 

 of America authorities are engaged in an extensive survey with a view 

 to limiting its distribution, and are testing their varieties for immunity. 

 Already it has been ascertained that several of the most important of 

 their varieties are apparently immune, and they are also importing 

 immune varieties from the British Isles with a view to testing these in 

 American infected soil. 



A few words on the common names of the disease may not be out 

 of place. 



There is naturally no history of such names as " Cauliflower 

 Disease," " Fungus," " Canker," &c, which are mere local names. 

 The term " Black Scab " appears, however, to be used first by Massee 

 in his paper in 1902 (48), and this and " New Potato Disease " were 

 the names commonly used up to 1908. In 1908, when more became 

 known of the disease, and it was obviously neither black nor 

 a scab, the Board commenced to use the term "Wart Disease," 

 and this appears officially in the leaflet issued in September 1908. 

 Previous to this Salmon had called it "Warty Disease" in his 

 paper in Gardeners' Chronicle, December 7, 1907. Still earlier it 

 had been referred tc in an Agricultural column of the Standard of 

 August 30, 1906, as " Yellow Wart Disease," while in a later issue 

 of the same paper {Standard, October 11, 1906) the Board of 

 Agriculture was taken to task for persisting in terming the disease 

 " Black Scab " and stating that it was commonly known amongst 

 growers as " Yellow Wart Disease.' Percival (56) pointed out that 

 Black Scab was misleading, and suggested " Potato Wart " instead. 



Since 1908, the term Wart Disease has come into common use, and 

 is used in all official documents. 



