3H 



ON THE BROWN-ROT OF THE SWEDISH TURNIP. 

 With a Note on the Same Disease of 

 the Cabbage. 



The brown-rot of the swede (Brasszca campestris rutabaga), 

 of which I propose to give a short account, has been under 

 my observation since 1898. During these five years I have 

 found it very generally prevalent throughout Northumberland, 

 occurring notably from October onwards in roots still growing 

 in the fields, and very frequently to be met with in the 

 store-heaps. In this locality the attack has been entirely 

 upon the swede, and its manifestation has been chiefly 

 confined to the root, the leaves presenting no sign of 

 infection so far as I have been able to observe. 



The disease is due to the action of bacteria, and has hitherto 

 in England remained undescribed upon the swede or turnip* 

 but its appearance has been noted upon the cabbage, and it is 

 known to have caused great damage to cruciferous crops in 

 America and on the Continent. It is, therefore, very desirable 

 that a general description of its characteristics should be given.* 



This brown-rot was first described by Pammel f (1895) as 

 present in Iowa among swedes and yellow turnips, in some cases 

 more than 50 per cent, of these crops being destroyed during 

 the wet season of 1892 and 1893. Pammel isolated a bacterium 

 which he proved to be the cause of the disease. Subsequently 

 Smith % extended his work and published accounts confirming 

 Pammel's earlier observations, and giving more detailed investi- 



* I have in course of preparation a scientific account dealing more specially with 

 the pathological features of the disease. 



t Bacteriosis of Rutabaga. Iowa Agricultural College. Bulletin No. 27, 1895. 



X Psezidomonas campestris ( Pammel ) the Cause of a Brown- Rot in Cruciferous 

 Plants. Centralblatt fur Bakteriologie u.s.w. Abt. II., Bd. III., 1897. The 

 Black-Rot of the Cabbage. U.S. Department of Agriculture. Farmer's Bulletin, 

 No. 68, 1898. The Effect of Black-Rot on Turnips. U.S. Department of Agri- 

 culture, Bulletin No. 29, 1903. 



