WART DISEASE OF POTATOS. 



305 



which even then were badly infected. These same grounds have been 

 used for the Board's trials since 191 5. In Shropshire a number of 

 adjoining infected gardens were used ; in Cheshire a badly infected 

 field. 



All the trials were similar, and consisted of 



(1) Variety trials for immunity, 



(2) The testing of possible remedies. 



Of the latter it may be said at once that no substance tried then 

 or since has proved a remedy (3), (46), (70), (71), (72). The common 

 remedies — lime, salt, sulphur, soot, &c— by themselves and in. various 

 combinations were tried, as well as chemicals which theoretically might 

 prove a cure. Eriksson (25) reported that he had killed the 

 " contagious matter in the soil" by means of formalin. This had 

 been tried previously in England, and after his report it was again 

 tried, but the next crop of potatos was badly attacked. As regards 

 the variety trials, nearly all the well-known varieties, such as ' King 

 Edward/ ' Up-to-Date/ 'Epicure,' ' Evergood/ &c, were found to 

 take the disease, but the following were free from it, thus confirm- 

 ing the immunity: ' Langworthy ' ('What's Wanted'), 'Golden 

 Wonder,' ' Abundance,' ' Conquest,' and ' Snowdrop.' Rogues in these 

 varieties were found to be attacked. 



In 1909 flowers of sulphur which had been reported on favourably 

 as a cure by a number of people, was also tried by presenting sufficient 

 of the material to test it to cottagers with infected land. Un- 

 fortunately, in no case was there less disease present, but many of 

 the recipients reported that the sulphur acted as a manure, and that 

 treated rows gave heavier crops than untreated rows. 



The immunity tests were repeated in 1910 (5) with additional varie- 

 ties, and as a result the immunity of the above varieties was con- 

 firmed and others were found resistant. These were ' Aberlady 

 Early,' ' Southern Queen,' 1 Favourite,' ' Supreme,' ' Crofter,' ' Laird,' 

 ' Provost,' ' White City,' and ' Peacemaker.' 



Elsewhere ' Champion,' ' St. Malo Kidney,' ' Rector,' and ' School- 

 master ' were also reported as immune. 



The same season (1910) the Board distributed to centres selected . 

 by the author small lots of 'Conquest,' 'Langworthy,' and ' Golden 

 Wonder ' for planting by cottagers and allotment holders in infected 

 soil, as it was felt that the results of experiments on scientific lines 

 might be different when carried out in small gardens. These varie- 

 ties under these conditions proved to be resistant and gave satis- 

 faction to many who previously could not grow potatos in their gardens 

 owing to the serious infection of their soil. 



The Board of Agriculture did not initiate further experiments 

 after 1910, but in 1911 and 1912 Mr. Malthouse of the Harper Adams 

 College was assisted by a grant from the Board and continued both 

 variety and fungicide experiments, greatly increasing the list of 

 potatos resistant to the disease. A full account is given in the College 

 Bulletin 8 (46), but it maybe mentioned here that French, German, 



