92 THE ROYAL SOCIETY OF CANADA 



types; nevertheless such an effort is of great use in routine description, 

 and for arranging and cataloguing cultures. 



In the present study we have worked out in detail the pathogenicity 

 of an organism belonging to the 'soft rot' type, which was the cause of 

 a rotting disease in turnips, and we have described its morphological and 

 cultural features in detail. Several important peculiarities have been 

 noticed, and as far as possible these have been photographed. 



Our attention was first directed to this disease by Mr. Paul A. 

 Boving, B.A., B.S.A., assistant in the cereal husbandry department 

 of Macdonald College, and in charge of all the root experiments. Mr. 

 Boving has contributed the field notes of the disease, and has given 

 a number of excellent photographs of the naturally occurring disease, 

 one of which, Fig. 12, is reproduced. 



Field Notes on the Disease. 



The disease was observed during the first week of September, 1912, 

 and the outbreak continued until the end of October, when all roots 

 were pulled and the diseased ones thrown aside. The percentage of 

 diseased plants is shown in the following table: — 



Per cent, diseased plants in turnips of diiïerent classes during 1912: 



6 varieties globe-shaped, white fleshed 12 • 0% 



4 " long " " " 8-5% 



4 " globe " yellow " 13-7% 



7 " long " " " 5-4% 



Average 9 ■ 5% 



From this it would appear as if the long-shaped, yellow fleshed 

 were more resistant against the disease than the others. If, however, 

 the figures for the duplicate plots of this class are examined more closely, 

 we find in some cases a greater difference between two plots of the same 

 variety than between any two classes compared with each other. 



Per cent, diseased plants in the long-shaped, yellow-fleshed class of turnips, 1912. 



A-plots B-plots 



Yellow Tankard, Pajbjcrg 2 (Helweg) 4 



(Faber) 4 



(S.F.A.) 



Bortfelder (W.) 2 



(A.D.C.S.) 6 



" (S.F.A.) 2 



(Sv.) 



9 % 1-4 % 

 1 % 8-4 % 



7 % 2-1 % 



1 % 13-7 % 



2 % 10-0 % 



8 % 9-3 % 

 7 % 9-3 % 



Average 3-07% 7-74% 



