THE MIGNONETTE DISEASR 



123 



are described. One of the fullest accounts of the carna- 

 tion rust, by Professor Arthur, occurs in The American 

 Florist, Feb. 18, 1892. 



The Mignonette Disease 



Cercospora resedce 



Mignonettes frequently suffer from a disease which 

 mav first be noticed, '^^ either as minute pale spots with 

 brownish or yellowish borders — little sunken areas in 



FIG. 54. MIGNONETTE DISEASE. 

 a, Spore; b, spore stalks; e, germinating spore. Magnified. 



the succulent tissues of the leaf — or as reddish discolora- 

 tion s which spread over the leaf, and finally develop 

 into these pale spots or patches." These spotted areas 

 are portions of the leaf which the fungus has invaded 

 and destroyed. As the mycelium develops within the 

 leaf they increase in size, and finally involve so much of 

 the surface that the leaf wilts and withers ; the whole 

 plant sometimes looks as if it had suffered severely from 



