l68 Diseases of Greenhouse Crops 



mented protoplasm of the base. They are hyaline, 

 thin walled, and vary frcnn oblong to linear in shape. 

 The chlamydospores are thick walled, dark brown 

 bodies borne on the same mycelium as the endo- 

 spores. This type of spore is formed in great abun- 

 dance on the host and particularly within the af- 

 fected tissue. The ascospores are lenticular in shape 

 and are borne in asci or sacs within black perithecia. 

 This stage, however, has not been found on the pea 

 nor in pure culture. 



Control. Since the causal organism is introduced 

 with infected manure or soil, sterilizing the beds 

 with steam or formaldehyde (see pp. 32-43) is 

 recommended. 



Powdery Mildew, see Bean, p. m. 



Pod Spot 



Caused by Spherella pinodes (Berk, and Bl.)] 

 Niessl. 



Symptoms. On the stem the trouble appears as 

 numerous elongated lesions. These spread to such 

 an extent as actually to girdle the aflEected stem. On 

 the leaves are formed oval spots, grayish in the cen- 

 ter, and limited by a dark band. The pods, too, 

 become badly attacked and the symptoms there re- 

 semble those on the stems. The disease works its 

 way from the pods to the seed within. 



The Organism. The causative fungus has two 

 spore stages. The pycnidia bear the hyaline, two- 

 celled spores, and are formed within the dead tissue 



