1920.] 



The Distribution of Wart Disease. 



863 



THE DISTRIBUTION OF WART 

 DISEASE, 



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



Dejnifi/ Controller of Hort/iculture, Ministry of Agriculture 

 and Fisheries. 



In the first part of this article, 'published in last month's 

 issue, an account was given of the possible origin of wart 

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

 and its spread in recent years. 



Influence of Disease on the Varieties grown. — In dealing 

 with a disease which is only virulent on certain varieties of 

 potatoes, it can be readily seen that the variety of potato com- 

 monly grown at certain periods would influence enormously the 

 rate of spread of the disease. Early varieties at any time 

 apparently exercise but little influence on the spread of the 

 disease, so that only second earlies and maincrop will here be 

 mentioned. The table below gives a list of those potatoes which 

 have been extensively grown in this country since 1 850, together 

 with the approximate date of the introduction of the variety to 

 commerce. It must be remembered that the varieties would 

 take some five or six years to establish themselves, so that their 

 influence v/ould not be apparent until some ten years or so after 

 the date oiven. 



Variety. 

 Victoria 

 Eegents 

 Champion 

 Magnum Bonuin 

 Maincrop 

 Abundance 

 Bruce ... 

 Up-to-Date 

 British Queen ... 

 President 

 King Edward ... 

 Great Scot 

 Arran Chief ... 



Date of Introduction. 

 1850 

 1852 

 1867 

 1876 

 1882 

 1886 

 1887 

 1893 

 1894 

 1901 

 1902 

 1911 

 1912 



There is no reliable evidence to show that Wart Disease 

 existed in this country in the days of the varieties Victoria, 

 Regents and INIagnum Bonum, nor do we know^ whether 

 Victoria was susceptible to, or immune from, Wart Disease, 



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

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



