864 The Distribution of Wart Disease. 



or whether the two late varieties were susceptible. Cham- 

 pion, Abundance and Maincrop, which were extensively 

 grown after the Eegents were given up, were all immune, so 

 that in any case, had the disease existed at this period, little 

 damage would have been caused. About 1877 Mr. Archibald 

 Findlay, of Fife, commenced raising new varieties of potatoes. 

 Working on new lines he endeavoured to breed varieties 

 resistant to " Bhght " {Phytophthora infestans), and did 

 yeoman service to the potato industry of this country by intro- 

 ducing to it such magnificent cropping new varieties as the 

 Bruce m 1887, Up-to-Date in 1893, and Britis'h Queen in 1894. 

 These varieties of potatoes possessed just those qualities that 

 the previous ones had lacked, viz., good shape, colour, 

 quality, and a great cropping capacity, so that after a very few 

 years — from about 1900 onwards — British Queen and Up-to- 

 Date became the varieties popularly grown. Incidentally, 

 these varieties were susceptible to Wart Disease, and it is 

 probable that the disease, which had appeared just prior to this 

 time, finding suitable host plants, firmly established itself 

 during this period. 



President and King Edward were introduced to the potato 

 industry soon after 1900, and, being susceptible, these varieties 

 in no way tended to check the disease. Arran Chief, on intro- 

 duction into Scotland, about 1912, was immediately taken up by 

 growers and largely grown. This variety has .been for several 

 years one of the most susceptible varieties in existence, and the 

 rapid spread of the disease in recent times must be attributed 

 to the widespread growing of this variety. In so far as reliance 

 can be placed on official statistics, the fact that 66 per cent, of 

 the cases of Wart Disease occurring in England were on Arran 

 Chief gives support to the above statement. 



During the 'nineties, our British potato breeders were 

 endeavouring to produce varieties resistant to the destructive 

 " blight " {Phytophthora infestans) , and to a large measure 

 they succeeded, but at the same time the industry was pre- 

 sented with varieties highly susceptible to Wart Disease. 

 Their newer problem since 1908 has been Wart Disease, and 

 the majority of breeders are now working to produce immune 

 ▼arieties. So far as Second Earlies and Maincrop are con- 

 cerned, they have met with considerable success, and in a few 

 years the potato crop will be comparatively safe from this disease. 



Mr. Findlay, of " Up-to-Date " fame, has now^ introduced 

 the Immune Majestic; Mr. McKelvie, the producer of Arran 

 Chief, has given us Arran Eose, Ally, and Arran Comrade; 



