40 A SOFT ROT OF THE CALL A LILY. 



affects the h^^acinths indicates that it is not the same as Heinz's 

 hyacinth germ, which attacked the plants readily and destroyed them 

 rapidly when inoculated by either of the methods used in these tests. 

 Heinz's org-anism {Bacillus hyacinihi septicns) does not liquefy gelatin, 

 while the opposite is true of the calla organism. The colonies in 

 plate cultures are round and when grown on sterile potato they are a 

 dirty j^ellow color. The colonies of the calla organism are usually 

 radiating and on potato they produce a brownish color. 



Potter'' s Pseudomonas destructans/^ — Potter's organism, when grown 

 in a solution containing sugar, liberates carbonic acid gas. The calla 

 organism is not a gas producer. Colonies in plate cultures are round, 

 and Avhen grown on vegetables the end reaction is acid. The calla 

 organism usually produces radiating colonies, and on vegetables the 

 end reaction is generally alkaline. Pseudomonas destructans has but 

 one ilagellum while the calla organism has several flagella. 



Likewise in comparison with other forms the calla germ does not 

 agree in all particulars with any other known organism, and the 

 writer therefore proposes for the calla-rot germ the name Bacillus 

 aroldede. 



ORIGIN AND SPREAD OF THE DISEASE. 



The calla rot has been reported from the Western, Central, and 

 Eastern States, i. e., from the Atlantic to the Pacific. It therefore 

 appears to have spread over the entire calla-growing section of the 

 United States, but it is much more destructive in some portions of 

 the countr}^ than in others. It causes a loss of thousands of dollars 

 annuall}" and has become so destructive in some sections that the 

 growers have either abandoned the calla altogether or have greatly 

 reduced the space and time that they have heretofore devoted to this 

 plant. It is therefore of the highest importance that the grower 

 should know the source of this disease and the w^ays in which it may 

 spread from place to place and from plant to plant. 



Calla corms that are attacked late in the season go into their resting 

 stage in a partly decayed condition. If the attack has been slight the 

 infected spot will dry down and may be overlooked when corms are 

 selected the following season for growing calla plants. When callas 

 begin to grow from such corms the organisms which have remained 

 dormant during the resting period of the corm are revived and decay 

 is started afresh. Since this organism may remain dormant for 

 months without its life becoming extinct, it may be spread from one 

 locality to another, and even from country to country, whenever dis- 

 eased corms are transported. It is undoubtedly in this manncM- that 

 the disease has become so widespread in this c-ountry. 



« Potter, M. C. Ue1)er eine Bakterienkrankheit der Ruben. Central})latt f. Bakt. 

 u. Parasiteiikunde, Bd. VII, II. Abt., 190^ "u. 282, 353. 



