B. P. I.-99. V. P. P. I—Uo. 



A SOFT ROT OF THF CALLA LILY. 



INTRODUCTION. ^ 



Under favorable conditions the t-alla lily has heretofore been one of 

 the most satisfactory plants pnxliK'od either in the <)])en or under 

 glass. In most parts of the United States the calla will grow out of 

 doors and will live and thrive from year to y(nir even in the northern 

 latitudes, especially if the corms" are protected during the winter 

 season. As a marketal)le product, however, it is more protital)le if 

 grown under glass, where under pi-ojK'r conditions the plants may be 

 forced and the tiowers consequently produced in great a])undance at 

 the time when they will he in greatest demand. It is under these con- 

 ditions of forced growth that the plants seem to l)e most susceptible 

 to disease. 



The profits which arise from calla growing are derived either from 

 the sale of the corms or of the flowers, or from both. A bed of a 

 thousand corms, for example, will under normal conditions produce 

 5,000 flowers, which ordinarily will sell for about i?l,0<K>. The corms 

 are grown either in solid beds or in pots. As a rule the best results 

 both as regards the size and the number of flowers produced are 

 obtained from the solid bed. The flowers are always delicate and can 

 not be satisfactorily shipped long distances, while the corms, on the 

 other hand, may be transported for thousands of miles without injury. 



There are several diseases to which the calla is susceptible, but the 

 most serious one with which the growers have had to contend is the 

 soft rot that forms the subject of this bulletin. This disease has 

 recently made its appearance in the various parts of the United States 

 where callas are cultivated and has caused enormous losses to the 

 growers, rendering the production of this hitherto profitable plant 

 very uncertain. 



The soft rot of the calla w^as brought to the attention of the writer 

 in the autumn of 1899, and it has been under his observation and 

 stiidv since that time. While there are some points that need further 



a The true botanical name corm is used in this bulletin instead of the common but 

 incorrect term bulb. 



