226 



DISEASES OF ECONOMIC PLANTS 



CELERY 



Leaf spot, early blight, cercosporose (Cercospora Apii Fr.). 

 — The leaf spot is common in both Europe and America, 

 constituting proljably the most destructive disease to 

 which the celery plant is subject. It is known from 



Fig. 106. ^ Cauliflower affected with black rot. 

 (Pseudomonose). Original. 



Colorado to New Jersey. In Florida in 1906 it is said to 

 have injured 80 per cent of the crop. The crop is largely 

 reduced, and the unsightliness of the spots injures the 

 salability of the product. 



The spots appear first upon the outer, older leaves as 

 pale yellowish regions, showing from both sides of the leaf. 

 They are irregular with slightly raised border and are 



