BACTERIA WHICH CAUSE PLANT DISEASES 405 



Morphology, Culture and Physiology. It is much like 

 the preceding organisms and typical of the genus. Acid and 

 gas production are peculiar in that no gas is produced in 

 sugar broth, though growth occurs and acid develops, while 

 some gas is said to develop in asparagin broth and in milk, 

 the gas consisting of carbon dioxide. 



Pathogenesis. The organism apparently invades the 

 melon from the soil through cracks or injuries. Like the 

 preceding organism it is capable of dissolving the middle 

 lamella and of producing thereby a typical soft rot. 



ERWINIA PHYTOPHTHORA 



Synonym. Bacillus phytophthorus. 



This organism has been described from Europe and 

 America as the cause of the basal stem rot of the potato. 

 It also causes rotting of the tubers. It closely resembles 

 the other members of the genus in its morphology and 

 culture. 



LACTOBACILLUS TEUTLIUS 



Synonym. Bacterium teutlium. i 



This organism is described as the specific cause of a soft 

 rot of the sugar beet. It is apparently culturally and 

 morphologically most closely related to the lactic acid bac- 

 teria, particularly those members of the genus Lactobacillus 

 most important in the production of acid in the fermenta- 

 tion of ensilage. 



Morphology. The organism is a nonmotile, Gram- 

 positive rod, .8 X 1- 5 M, without capsules or spores and 

 staining readily with the ordinary aniline dyes. 



Cultural and Physiological Characters. On media not 

 containing sugar, growth is usually scant, slow, white and 

 not viscous. On agar it tends to grow into and penetrate 

 the medium. In the presence of cane sugar the develop- 

 ment is much more rapid and abundant, becoming watery 



