SCHIZOMYCETES. BACTERIA 133 



XIII. SOFT ROT OF THE CALLA 

 Bacillus aroidecz Townsend 



TOWNSEND, C. O. A Soft Rot of the Calla Lily. U. S. Dept. Agl., Bureau 

 Plant Industry, Built. 60 : 1-44. pis. i-g. 1904. 



This organism, very closely related to the preceding, has been 

 found to be the cause of a serious soft rot of the calla lily, 

 destroying the plants at about the time of flowering. The seat 



FIG. 39. ISOLATION CULTURE OF BACILLUS AROIDEA? TOWNSEND. 

 (Photograph by C. O. Townsend) 



of the disease is principally in the corms, petioles, and flower 

 stalks. If inoculated into a wound, the bacillus will produce a 

 rot in many raw vegetables, and also in some green fruits. The 

 cultural characters have been indicated. According to Town- 

 send it produces on agar very characteristic radiate colonies 

 (Figs. 38, 39) at or near the optimum temperature. The rot 

 in the calla may be prevented by a careful selection of the corms 

 and by changing the soil in the beds every three or four years. 



