Palm Diseases 307 



The soil best suited to palm culture is that which 

 is made up of two-thirds rotted sod and one-third 

 well rotted cow manure. Palms do poorly when 

 treated with commercial fertilizers, and when its 

 root system is disturbed, hence they should be re- 

 potted only when absolutely necessary. Palms love 

 partial shading (fig. 60) and a moist atmosphere. 

 The temperature should be allowed to go below 60 

 degrees F. at night. The foliage should be kept 

 free from dust. 



Diseases of Palms 



Forced palms are subject to less disease than 

 those grown out of doors. Nevertheless, some of 

 these indoor diseases often become very troublesome 

 and serious. 



Smut 



Caused by Graphiola phcenids Port. 



Symptoms. Smut is a common disease on both 

 greenhouse and outdoor palms of all sorts. The 

 affected areas on the leaf become mottled with yel- 

 low, and upon the surface pustules appear (fig. 

 61, a.). These are cup-shaped -conceptacles pro- 

 duced by the causal fungus, and in which the spores 

 are borne. The spore pustules consist of a firm, 

 dark colored exterior wall, enclosing a more deli- 

 cate inner covering which contains a mass of thread- 

 like filaments on which the spores are produced 

 (fig. 61, b.). The spore pustules become very nu- 

 merous and the affected foliage slowly shrivels. 



