62 BULLETIN 727, XT. S. DEPARTMENT OF AGRICULTURE. 



These results indicate that lower concentrations are fairly effective. 

 For practical use, however, the standard strength of 1 to 1,000 is 

 preferable. 



In the large-scale field tests summarized in Table VIII, the deter- 

 mination of the value of seed disinfection as a control measure is 

 complicated by the relatively few cases of anthracnose occurrence 

 in which there was no possibility of soil infestation. Disregarding 

 this contingency, it is rather striking that the disease was present 

 in only 14.6 per cent of the fields planted with treated seed as com-> 

 p'ared with 23.3 per cent of the controls. This indicates a prevention 

 of disease in 8.7 per cent of the fields, or, on a comparative basis, 

 prevention of 37 per cent of the cases that would normally have 

 occurred. Eliminating all cases possibly attributable to overwinter- 

 ing, we find the disease present "in 1.3 per cent of the fields planted 

 with treated seed as compared with 6.8 per cent of the controls, indi- 

 cating a net gain of disease prevention in 5.5 percent of the fields, or, 

 on the comparative basis, a prevention of 80 per cent of the out- 

 breaks. 



In conclusion, it may be said that a successful control of anthrac- 

 nose may quite possibly be secured by the use of disease-free seed 



in clean soil. 



SUMMARY. 



Anthracnose of cucurbits is caused by the fungus ColletotricJium 

 lagenarium (Pass.) Ell. and Hals. 



The hosts are limited to the family Cucurbitacese. Those of eco- 

 nomic importance are the cucumber, muskmelon, and watermelon. 

 The disease is common among Lagenaria gourds. The following 

 cucurbits are added to the list of hosts: Benincasa cerifera, Tricho- 

 santhes colubrina, Cucumis dipsaceus, C. melo var. dudaim, and C. melo 

 var. Jlexuosus. Fruit infection occurred in Cucumis anguria and C. 

 anguria var. grossulariae. Anthracnose was not found as a vine dis- 

 ease in the genus Cucurbita, which includes squash, pumpkin, and 

 certain gourds. Beans are not susceptible. 



This disease was first noticed in 1867 in Italy among Lagenaria 

 gourds. Later, it appeared on melons in France, and it now occurs 

 throughout Europe and the eastern United States wherever the 

 hosts are grown. 



Serious losses are caused in the watermelon-growing industry of 

 this country and among cucumbers grown for slicing purposes. 

 Since the disease is more serious on crops in which the fruits are long 

 exposed to infection, the losses in the cucumber-pickle crop are not 

 as great. 



Leaves, stems, and fruits are attacked. Leaves and even whole 

 runners and plants may be killed, and fruits may be blemished or 

 become malformed. The lesions increase rather indefinitely in size. 



