ROTS. 511 



Closely related organisms are B. solanisaprus Harrison, and B. atro- 

 septicus van Hall. 



Erwin Smith describes the causal organism as a non-spore forming bacillus, motile 

 by means of peritrichiate flagella. It stains with the ordinary stains, but is Gram-nega- 

 tive. The growth is grayish-white on agar and on gelatin plates large, round, white 

 colonies develop promptly. Gelatin is liquefied with funnel-shaped liquefaction. On 

 cooked potato, white to yellowish growth. Raw potato, white growth and black stain . 

 There is a slow acid coagulation of milk with precipitation of casein and reduction of 

 litmus. Thick pellicle and heavy precipitate in potato juice. No growth in Cohn's 

 solution. Moderate production of hydrogen sulphide. Nitrates reduced. No indol. 

 Acid from dextrose, saccharose, lactose, maltose and galactose. Some gas from 

 inosite, lactose and mannite. Facultative anaerobe. Optimum temperature, 28 

 to 30. Thermal death-point, 47. 



SOFT ROT OF CALLA LILY. 

 Bacillus aroidese. Townsend.* 



A soft rot of the calla lily, distinct from other soft rots, is scattered 

 over the calla-growing sections of the United States. The disease starts 

 at the top of the corm and causes a rotting of the plant at or just below 

 the surface of the ground. As a result the leaves and flower stalk turn 

 brown and fall over. The healthy corms are white, but the infected 

 ones are brown, soft and watery. 



It is believed that the causal organism lives in the soil and enters the 

 plants through wounds. The disease is undoubtedly spread from one 

 locality to another by shipping slightly diseased corms. 



As a means of control, only sound corms should be used, and the 

 soil in the calla beds should be changed every three to four years. 



SOFT ROT OF CARROT AND OTHER VEGETABLES. 

 Bacillus carotovorus Jones. 



A number of the cultivated plants of the north temperate zone, 

 notably those grown for their root crops, suffer, at times, from a bacterial 

 rot caused by a liquefying bacillus. Although probably as widely dis- 

 tributed as any microorganism parasitic upon plants, it was not described 

 until 1 901. f 



* Townsend, C. O., Bui. 60 Bur. Plant Ind., U. S. Dept. Agr., 1904. 



"f" Jones, L. R., "A Soft Rot of Carrot and Other Vegetables," isth Report Vermont Exp. 

 Station, p. 299, 1901. 



