14 



A SOFT ROT OF THE CALL A LILY. 



mis remains intact, thus presenting the appearance of thin-walled tubes 

 filled with a soft substance. The roots remain attached to the corni and 

 eventually the slimy contents dry up and only the dead skin of the roots 

 remains. "When the disease begins its attack below the surface of the 

 ground the lower portion of the corm frequently rots away, causing the 

 plant to fall over Avithout having previously given an}' indication of dis- 

 ease. An examination of the decayed corm shows that only a small part 

 of the upper portion of the corm, with a few side roots, remains. The 



Fig. 2.— a partly decayed calla corm. 



latter become less and less numerous as the disease advances, until at last 

 they are unable to support the weight of the leaves and flower stalks. 

 If the conditions for the development of the disease are unfavorable 

 after the corms are affected, the softened spots will dry down, sinking 

 below the surrounding portion of the corm and ])ecoming darker col- 

 ored. In these spots the disease will often remain dormant until the 

 conditions for the development of the organism again become favor- 

 a))le. In this way the disease is carried over from season to season, 

 and it may l)e transported long distances. 



