192 Diseases of Greenhouse Crops 



acervuli a black appearance. The conidiophores are 

 short, and the conidia, oblong, hyaline and one- 

 celled. 



Control. Anthracnose depends upon a moist at- 

 mosphere for its activity. Spraying with Bordeaux 

 is recommended. 



Leaf Mold 



Caused by Cladosporium fulvum Cke, 



Leaf mold is very troublesome in the greenhouse. 

 In some of the Southern States, however, it is found 

 on field tomatoes also. The disease is favored by 

 a damp, moist atmosphere. 



Symptoms. The mold appears as rusty ciimamon, 

 colored irregular, feltlike spots on the underside of 

 the leaf (fig. 36, b), the upper part of which turns 

 brown, then black. The affected foliage finally curls 

 and dies. 



The Organism. The conidiophores of the fimgus 

 break through the cuticle of the epidermis in a dense 

 crowded mass. The conidia are few and are borne 

 on the tip ends of the condiophores, which are spar- 

 ingly branched and knotty. The conidia are elliptic 

 or oblong (fig. 36, c), 1 septate. 



Control. The effects of the disease are seldom 

 disastrous if infection starts when the fruit has set 

 and is well developed. An early infection when 

 the plants are still young may result in the failure 

 of the crop. Careful and thorough spraying with 

 Bordeaux 4-4-50 before the disease appears is rec- 

 ommended. Spraying should be done once every 



