Palm Diseases 309 



nute brown spots. These are often so numerous as 

 to involve the entire leaf, causing it to dry up and 

 die (fig. 61, c). This trouble is very common 

 on greenhouse palms, especially on those which 

 are kept in too long under shade. It is common 

 on Phcenix canariensis, on P. tenius and on P. re- 

 clinata. The disease undoubtedly must have been 

 introduced from Europe with imported stock. Tre- 

 lease* observed it in America in 1897. 



The Organism. The sporodochia are superficial 

 black, and dense (fig. 61, d), visible to the naked 

 eye as a black mold. The spores are borne singly, 

 are olive brown in color, and are many times sep- 

 tate (fig. 61, e and f.). 



Control. The disease seldom occurs in well 

 lighted and well ventilated greenhouses. Where 

 the disease makes its appearance, more attention 

 should be given to the ventilation, and the shad- 

 ing should be gradually diminished. All infected 

 material should be cut off and destroyed by fire; 

 the plants should be sprayed with a standard 

 fungicide. 



Leaf Blight 



Caused by Pestalozzia pdmarum Cke. 



Symptoms. This disease appears as transparent, 

 dirty white spots at the tip of the leaflets or at 

 the axils. The spots spread quickly and it is not 

 imcommon to find numerous leaves killed, and the 

 affected plant thereby badly disfigured. As the 



•Trelease, W., Kept Mo. Bot. Gard. 9: 159, 1898. 



