948 



The Distribution of Wart Disease. [Jan., 



As a result of the trials in 1912 and 1913, the following 

 twenty-seven varieties were also proved immune : — 



Early. — Peerless Rose, Field Ashleaf, A.l, Gelly's Early, Juni, and 

 North Pole. 



Second Early. — King George V, Entente Cordiale, Seedling B4, Welt- 

 wunder, Table King, and Adirondack. 



Main Crop. — The Lochar, Great Scot, Culdees Castle, Irish Queen, 

 St. Malo Kidney, Dalmeny Sun, Flourball, Variety unnamed 

 (Ministry of Agriculture), Alice, Callico, Unique, General Kuroki, 

 Brocken, General Nodzu, and Borderer. 



There were thus after 1913 about fifty-three varieties of pota- 

 toes of importance known to be immune. 



The Ormskirk Trials. — By 1914 the disease, which had 

 greatly increased in the South Lancashire area, was so destruc- 

 tive to the potato crop in the fields, that the late Mr. John Snell, 

 then Inspector for the Ministry of Agriculture in charge of the 

 Northern district, commenced trials in what may be termed the 

 great potato-growing area of the North of England. 



With the support of the Lancashire farmers and a few of the 

 Scotch seed potato growers, Mr. John Snell in 1915 commenced 

 trials on the land kindly lent for the purpose by the Guardians 

 of the Poor Law Institution. The course pursued was : — 



1. To test all the varieties of potatoes in commerce in this country in 



order to discover which were immune from Wart Disease. 



2. To demonstrate the disastrous results of planting non-immune varieties 



on land infected with Wart Disease. 



3. To record accurate characteristics of individual varieties. 



4. To classify varieties to types. 



5. To discourage the use of synonyms. 



6. To encourage the raising of new varieties. 



7. To discover a means of sterilising infected soil. 



Number of Varieties tested. — It was seldom that any potatoes 

 were purchased for planting in the trials. All persons were 

 invited to send seed of any kind, and the way in which the trade 

 generally took advantage of this invitation is shown by the 

 following figures : — 



1915 there were 94 varieties tested. 



1916 „ „ 159 „ 



1917 „ „ 140 „ 



1918 „ „ 301 



1919 „ „ 472 varieties and 839 seedlings. 



