Chrysanthemum Diseases 243 



Powdery Mildew 



Caused by Oidium chrysanthemi Robh. 



This is a very common trouble of indoor chr3rs- 

 anthemums. Affected leaves become covered with 

 a powdery white growth. It seems that the Oidium 

 or summer stage is the only one that occurs on af- 

 fected plants. The winter or ascus stage has not 

 yet been recorded. The trouble may be controlled 

 in the same way as the rose mildew (see p. 323). 

 Some growers prefer to use sulphur by mixing it 

 with an oil and applying it to the steam pipes as a 

 paint. 



Cineraria (^Cineraria cruentct) 



Cultural Considerations. The culture of this 

 plant is very simple. However, it should be kept 

 in mind that it is injured by hot dry air and sensi- 

 tive to slight frost. The plant should be syringed 

 practically every day, winter or summer. It also 

 requires a cool shaded part in the house. 



Fungi Recorded on the Cineraria 



The Cineraria, it seems, is very hardy. The fol- 

 lowing fungi have been found on weakened or dead 

 parts of the plant: Mcidium cineraria Rosti, Asco- 

 chyta fibricola Sacc, Coleosporium sonchi (Pers.) 

 Lev., Leptosphsria vagahunda Sacc, Puccinia erio- 

 phore Thum. 



