THE FUNGI WHICH CAUSE PLANT DISEASE 



41 



B. betae Mig. is reported as the cause of gummosis of beet.^" 



B. brassicsevorus Del. isolated from diseased cabbage ^"^ is per- 

 haps identical with Pseudomonas fluorescens. See page 27. 



B. carotovonis Jones. (Group number 221.1113022.) From 

 agar 1-2 days- old as 

 short or long rods, in 

 short or long chains. 

 0.7-1.0 X 1.5-5 It, com- 

 monly 0.8 X 2 n; ends 

 rounded. No spore; 

 flagella 2-10, peritri- 

 chiate; no capsule; 

 Gram negative. White 

 on all media. Agar 

 slope filiform to spread- 

 ing, glistening, opaque 

 to opalescent. In gela- 

 tine stab; liquefaction 

 crateriform to infun- 

 dibuliform. Broth 

 clouded, pellicle thin 

 to absent, sediment 

 flocculent; milk coagu- 

 lated. Agar colonies, 

 roimd, smooth, entire 

 to imdulate, amor- 

 phous or granular. 

 Some gas in dextrose, 

 lactose and saccharose, nitrates reduced to nitrites; indol feeble. 

 T. D. P. 48-50°. Opt. 25-30°. 



A considerable number of cultivated plants suffer soft rot from 

 the attacks of a non-chromogenic liquefying bacillus. Among the 

 plants so affected are cabbage, turnips and other crucifers; parsnip, 

 carrot, mangel, sugar-beet, potato, celery, tomato, Jerusalem 

 artichoke, asparagus, rhubarb, onion and iris. 



In 1901, Jones reported an organism isolated from rotting carrots 

 which he named B. carotovorus.io^- ">^ It disorganized tissue 

 by solution of the middle lamella; and infection into wounds led 



Fig. 27." 



-B. carotovorus wedging apart cells of the 

 carrot. After Smith. 



