Pansy Diseases 313 



Crown Rot 



Caused by Rhizoctonia solani Kuhn. 



Crown rot first appears in the form, of minute 

 lesions at the crown of the plant. These enlarge 

 and penetrate the tissue deeply until the plant is 

 practically girdled. Rotting usually sets in, where- 

 upon the prostrate branches, the leaves, and peti- 

 oles also rot. For a description of the causal or- 

 ganism and for methods of control, see p. 20. 



Pandanus or Screw Pine (Pandanus veitchii) 



Cutural Considerations. Screw pines are forced 

 extensively and are used as ornamental house 

 plants. They require a temperature of 65 to 70 

 degrees F. and must be exposed to full light, espe- 

 cially in the winter. The plant flourishes best in a 

 soil composed of two parts of heavy loam and one 

 part of thoroughly rotted cow manure. The soil re- 

 quired is a heavy loam to which is well worked in 

 one-third of thoroughly rotted cow manure. 



Diseases of the Pandanus. Pandanus is consid- 

 ered a very healthy plant. There are, however, 

 two fungi that proved injurious; these are Nectria 

 pandani Tul. and Melanconium pandani Lev., 

 which are known to be parasites. 



PoiNSETTiA (Euphorbia pulcheritnaj 



Cultural Considerations. Poinsettias are exten- 

 sively grown for the Christmas trade. The plants 



