2 BULLETIN 727, TJ. S. DEPARTMENT OF AGRICULTURE. 



production of new lesions is very rapid. Therefore, upon its hosts 

 under cultivation this disease often becomes epiphytotic and may 

 cause serious loss. While primarily a field-crop disease it also 

 occurs as a greenhouse trouble in cucumber culture. 



Anthracnose was noted as early as 1867, and it now occurs quite 

 commonly throughout Europe and the eastern United States. The 

 disease has received considerable attention from mycologists and 

 plant pathologists, and while diverse names were given to the causal 

 organism agreement seems to "have been reached that the several 

 descriptions apply to the same fungus. 



Among the outstanding disputed questions are that of the correct 

 generic name of the fungus and that of the relation of this fungus to 

 the causal organism of bean anthracnose. The latter question is 

 about settled. 



As in the case of other anthracnoses, the increased prevalence of 

 this disease following wet weather has been recognized. It seems to 

 be rather generally held that this anthracnose may be controlled by 

 spraying. 



In the present bulletin it has been the purpose to bring together 



and summarize the work of others upon this disease and to add 



something from observation and experiment. While a little is 



added to the record in the way of a description of the disease, the 



main purpose has been to learn more details regarding the life history 



of the causal fungus with relation to the disease and to devise a 



method of control with special reference to the disease as it occurs 



in the cucumber-pickle crop. The phases studied in particular are 



the overwintering of the parasite, manner of introduction into fields, 



mode of dissemination, method of host infection, and means of 



control. 



THE DISEASE. 



HOSTS. 



The economically important hosts of anthracnose are the cucum- 

 ber (Cucumis sativus), the muskmelon (Cucumis melo), and the 

 watermelon (Citrullus vulgaris). Among the noneconomic hosts are 

 gourds of the genus Lagenaria, two species of Cucumis, Benincasa 

 cerifera, and Trichosanthes colubrina. Saccardo (42, v. 3, p. 719-720) 1 

 lists Cucumis colocynthis as a host. 



While Farlow (17, p. 202) in his host index includes squash and 

 pumpkin as hosts, subsequent observations indicate that anthrac- 

 nose does not occur as a vine disease in the genus Cucurbita, although 

 it is reported on squash fruits (45, p. 15). More details regarding 

 the host range of the fungus are presented later, in the considera- 

 tion of pathogenicity. 



1 Th sprial numbers in parentheses refer to " Literature cited, " at the end of this bulletin. 



