FUNGI IMPERFECT! 



347 



Phyllosticta maculicola Hals. 1 is the cause of a very common 

 leaf spot of several species of Dracaena and Cordyline. The spots 

 are characterized by pale centers and reddish or purplish borders. 

 The disease is sometimes severe in greenhouses where it has long 

 been allowed to proceed unchecked. It is, however, readily pre- 

 vented by spraying with potassium sulfide 

 solution. 



Phyllosticta Ampelopsidis Ell. & Mart, is 

 perhaps closely related to the fungus causing 

 black rot of the grape. It has been injurious 

 during some seasons to the Boston or 

 Japanese ivy (Ampelopsis Veitchii). 



Phyllosticta Catalpae Ell. & Mart. 2 is 

 commonly found associated with Macro- 

 sporium Catalpce on the leaves of several 

 species of catalpa, but it is to the former 

 fungus that the production of the spot is 

 now ascribed. 



Phyllosticta Violae Desm. occurs upon 

 the violet and the pansy, often causing 

 blotch-like, pale spots which may result in 

 considerable injury. * 



Phyllosticta Magnolias Sacc. produces a 

 very definite spot disease on the leaves of 

 Magnolia grandiflora in Europe. 



Phyllosticta Pyrina Sacc. was long sup- 

 posed to be a chief cause of the apple leaf 

 spot so common in the United States. 

 Recent work indicates that the spot is in general primarily due to 

 Sphaeropsis, and that the Phyllosticta is to be regarded as taking 

 a minor part in the production of the injury. In fact, the failure 

 of inoculation experiments (see Sphaeropsis, p. 352) appear to 

 demonstrate that the latter is saprophytic, at least with respect 

 to penetration. 



1 Halsted, B. D. Blights of Dracaenas. N. J. Agl. Exp. Sta. Kept. 14: 412. 

 1893. 



2 Scribner, F. L. Leaf- Spot Disease of Catalpa. U. S. Dept. Agl. Kept. 

 (1887): 364-369. 



FIG. 168. DRAC^NA 

 LEAF BLIGHT 



