304 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



occupiers of these told him that the only variety they could grow 

 was ' Snowdrop,' which was not attacked, although all other varieties 

 suffered in their soil. I interviewed Mr. Swindell and Mr. Derry 

 and found that their soil was undoubtedly infected. Mr. Swindell 

 informed me that as far back as 1894 he had scarcely a sound root in 

 his garden, and that he grassed down a portion for five years only to 

 find the disease present when he again planted potatos. Both he and 

 his neighbour, however, could get clean crops of ' Snowdrop.' He had 

 tried quicklime, soot, and the usual remedies for disease without success. 

 As a result of these statements I made special inquiries of others 

 as to varieties free from attack, and was given various names, 

 especially " earlies " — which are not attacked before lifting unless 

 ground is very badly infected. In other cases I found supposed 

 resistance was due to the fact that the ground was unequally or very 

 slightly infected, but by a process of exclusion, owing to positive 

 evidence of its presence on many of the varieties growers considered 

 immune, I carne to the conclusion that ' Snowdrop,' ' Conquest,' 

 ' Golden Wonder,' and ' Langworthy ' were immune, or practically 

 so. What doubt there was, was due to occasional statements that 

 slight warts had been seen on some of the varieties, but we know now 

 that such warts were either on " rogues " or were due to Corky Scab 

 (Spongospora subterranea) . 



As a result of these and many other interviews with men who had 

 had the disease in their crops for years, and the sifting of scores of 

 statements, the following facts were ascertained, most of which were 

 incorporated into Leaflet 105 of the Board of Agriculture (1) :— 



(1) The disease was serious and infected the soil. 



(2) None of the ordinary remedies, lime, soot, salt, was of any 

 avail. Deep cultivation and the deep burial of the top spit was useless. 



(3) Plots grassed down for six years still produced diseased potatos 

 when they were planted again. 



(4) The spores of the fungus passed through animals unchanged 

 and were spread with the manure. 



(5) Certain varieties, ' Conquest,' ' Snowdrop,' ' Golden Wonder,' 

 and ' Langworthy ' resisted the disease, although ' Up-to-Date ' growing 

 alongside suffered severely. 



(6) Disease was spread by infected " seed " and manure, and 

 Scotch " seed " was not above suspicion. 



The Board (4) on receipt of this report resolved to have trials the 

 following season (1909) to confirm the observations, and requested 

 the Lancashire County Council (through their Education Committee), 

 the Harper Adams Agricultural College, Shropshire, and the Holmes 

 Chapel Agricultural College, Cheshire, to carry out a series of trials 

 in infected land. 



Three sets of trials were arranged by the Lancashire County Council 

 and one each by the two colleges. In Lancashire two trials were 

 on infected fields, one near Ormskirk, one near Manchester, while the 

 third was carried out in the grounds of the Ormskirk Workhouse, 



