[habkison-sadler] a bacterial SOFT ROT OF TURNIPS 95 



Both microscopic examination and replating on gelatine plates 

 and other media, yielded results which proved beyond doubt that the 

 artificially produced disease was identical with the original. 



It is of interest to note at this point that turnips may be badly 

 diseased and yet the appearance of the leaves and stem be such, that 

 any other than a careful ocular examination will fail to discern any 

 symptoms until the root is pulled or lifted. 



This condition, produced and noted experimentallly, is quite 

 usual in the field, and is shown well by Fig. 12. 



In both these trials the control plants which had been pierced 

 with a sterile needle did not show any sign of disease. The specimens 

 obtained experimentally, in addition to roots which had become 

 naturally infected in the field have been successfully preserved for 

 museum purposes in a 10% solution of 40% formaldehyde. 



At a later date, further trials were made with growing plants, in- 

 oculations being made from young agar cultures of the organism re- 

 isolated from the artificially produced disease described immediately 

 above. 



Fig. 7 is a photograph of one of the healthy turnip plants with 

 which these trials were carried out. Inoculations made in the 

 crown of the turnip, caused a rapid production of the disease, and in 

 five days the condition as shown in Fig. 8 was obtained. 



The leaves had drooped and withered to such an extent that 

 they hung over the side of the pot, and the root was so badly rotted 

 that it could not be lifted out of the soil. 



Fig. 9 represents a turnip which had been inoculated on the same 

 day as the one just described. In this case the inoculation was made 

 by needle puncture in the root, and twelve days later when the photo- 

 graph was taken, the leaves were all withered and partially rotted, 

 while the root was completely rotten. 



Fig. 13 is a photograph of a turnip which had been inoculated by 

 needle puncture in the crown, and while in 12 days time it looked 

 apparently healthy, sufficient evidence had already accumulated to 

 show that the condition of the leaves may not necessarily be a guide 

 as to the soundness of the root. 



When this photograph had been taken, the turnip was cut in two 

 and the rotted condition as shown by Fig. 14 was made evident. 



Replating on gelatin from these rotted turnips invariably yielded 

 an organism identical in all respects with the original culture. 



Fig. 10 is a photograph of a healthy cauliflower which was 

 subsequently inoculated by needle puncture in the heart and in the 

 stem with the turnip organism. 



