946 The Distribution of Wart Disease. [Jan., 



THE DISTRIBUTION OF WART 

 DISEASE.- 



H. V. Taylor, M.B.E., A.E.C.Sc, B.Sc, 



Deputy Controller of Horticulture, Ministry of Agriculture 

 and Fisheries. 



In the first and second parts of this article, published in 

 the November and December issues of this Journal, an 

 account was given of the possible origin of Wart Disease 

 in this country, the earliest traces of the disease in this 

 country, its spread in recent years and influence on the 

 varieties grown, and the incidence of transport and distribu- 

 tion on the spread of the disease. 



Control of the Disease, and Immune Varieties. — Whsn the 

 economic importance of Wart . Disease became apparent in 

 1907, it was necessary to establish trials of potatoes for the 

 purpose of investigating the disease, the manner in which 

 potatoes were attacked, and to discover, if possible, measures 

 of control. Much success has already been achieved, but the 

 trials generally have shown an amazing ignorance of the 

 vs^hole matter, especially of the subjects of soil sterilisation, 

 and the accurate life history of the organism. 



When the life history of the disease was being investigated, 

 it was established that the fungus was in the nature of a soil 

 organism, and it became necessary to discover means whereby 

 the spores of the fungus could be killed, and the soil sterilised 

 and made suitable once more for the production of clean 

 crops. 



Malthouse, Snell, and others have attempted such research, 

 but their investigations have met with no measure of success. 

 In another direction fruitful results have followed from 

 Mr. Gough's investigation of the disease for the Ministry in 

 Cheshire, when clean crops of Snowdrop, Conquest, and other 

 varieties growing in infected soil, were noted; in the following 

 year he stated that Snowdrop, Conquest, Golden Wonder, and 

 Langworthy were immune, or practically so. 



About this time the disease, which was causing considerable 

 damage to the farm crops in Lancashire, Cheshire, &c., 

 aroused alarm amongst all potato growers. It was apparent 



* Report of a paper read before the British Association for the Advance- 

 ment of Science, at Cardiff, on 24th August, 1920. 



