42 A SOFT ROT OF THE CALL A LILY. 



REMEDIES. 



Various methods have been used with the hope of finding some 

 remedy by which the progress of the disease could be stopped after 

 the phmts became infected. With this end in view the following 

 treatments were used: The partly decayed corms were treated with 

 the following substances, viz, air-slaked lime (two parts of the same 

 with one part sulphur), formalin (varying from 1 to 10 per cent), 

 corrosive sublimate, Bordeaux mixture, and copper sulphate solution. 

 These were used on plants in different stages of decay. In some cases 

 the soft part of the bulb was scraped away with a clean knife before the 

 substance was applied, and in other instances the material was placed 

 on the decayed part without in any way disturbing it. Sometimes 

 the softened part was scraped awa}^ and nothing was applied, simply 

 leaving the exposed surface to dr}^ down. None of the treatments, 

 however, was entirely successful. The lime and the lime and sulphur 

 retarded the progress of the disease, but in a few cases only did the 

 disease seem to be entirely eradicated. The solutions used appeared 

 to make no impression upon the disease unless they were of sufficient 

 strength to kill the plant. A few of the plants that were scraped and 

 left without further treatment did not suffer further deca}', but the 

 percentage of cases of this kind was very low. 



The successful treatment of the diseased plants in the bed was con- 

 sidered impractical )le, and preventive measures were then resorted to. 

 The soil was all remov^ed from the solid bed in which practically all 

 the callas had decayed, and this was replaced with fresh soil. At the 

 proper time a new set of corms was obtained, but they were not 

 planted directl^y in the bed. They were first carefully examined and 

 all that showed suspicious dark-colored spots were discarded. The 

 remainder were started in pots and then transplanted. This made it 

 possible to discard all plants which showed an}' indication of the rot 

 after growth began. As a result no disease appeared in the bed of 

 1,000 callas during the entire season. Tiie same soil was used the sec- 

 ond and third years and the same precautions were taken in regard 

 to putting into the bed oidy health}^ bulbs, «o far as possible, with 

 the result that while a few diseased plants appeared successful crops 

 of callas were grown. Plate I shows the third consecutive lot of 

 callas in the same bed since the crop was entirely destro3'ed by the 

 soft rot. Very little of the disease has appeared owing to the pre- 

 cautions that were taken in changing the soil and in selecting healthy 

 corms. 



It is safe, therefore, to state that the soft rot of the calla may be 

 prevented or held in check sufficiently for all practical purposes by 

 changing the soil every third or fourth year, depending upon the 

 number of cases of rot that appear, and by exercising due caution in 

 selecting only health}' plants for the bed. Diseased corms may often 



