Celery Diseases 



131 



septate. The pycnidia (fig. 18, b.) are olivaceous, 

 prominent, and abundant in the spots. The pycnio- 

 spores are filiform, straight or curved, hyaline and 

 many are septate (fig. 18, c). 



Control, According to Rogers,^ late blight may 

 be controlled by spraying with 5-6-50 Bordeaux. 



The first two applications should be given 

 to the seedlings in the seed bed. In the house 

 the first spraying should be administered about six 

 weeks after transplanting. Besides spraying, shad- 

 ing also seems to keep the disease in check. In 

 spraying celery, great care should be exercised to ap- 

 ply a fine mist. Where this is overlooked, large 

 drops of the Bordeaux mixture may be deposited 

 on the leaves and stalks, which upon drying may 

 deposit copper salt in sufficient quantity to injure 

 the consumer. Sprayed celery should be carefully 

 washed and dried before shipping. 



Early Blight 



Caused by Cercospora apii Fr. 



Symptoms. The trouble first appears on the 

 outer leaves as pale blotches visible on both sides 

 of the affected parts. The spots are irregular, an- 

 gular in outline, limited apparently by the leaf veins, 

 with slightly raised borders (fig. 19, a.). The spots 

 later turn brown to ashy white. 



The Organism. The conidiophores are usually 



*Rogers, S. S., California Agr. Expt. Sta. Bui. 208: 83-115, 191 1. 



