ANTHRACNOSE OF CUCURBITS. 



39 



in September. As may be noted in the accompanying diagram 

 (fig. 14), this field occupied a decided westward slope, and the rows 

 were parallel to the direction of the slope. Along the west side at 

 the foot of the slope were grown the various cucurbits mentioned in 

 the discussion of pathogenicity. While some anthracnose appeared 

 among these earlier in the season, it was confined to a few well- 

 defined centers. After the rains mentioned above, new even-aged 

 infection of anthracnose was found on September 12 on all of the rows 



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Fig. 14.— Diagram of field 1, Madison, Wis., 1916. The direction of the rows is indicated by broken lines, 

 the slope by the 4-foot contour intervals. Where not otherwise indicated the crop was cucumbers. The 

 original centers of anthracnose noted on July 27 are shown by the circles. The location of the seedlings 

 planted late in the summer is shown in the lower left corner. Water traps 5 to 8 are shown by trapezoids. 



of susceptible cucurbits, very evidently as a result of surface drainage 

 from the diseased field above. 



Still more convincing evidence was furnished by rows of cucumber 

 seedlings planted late in the season between the rows in field 2 and 

 on the west edge of field 1 (fig. 14). On September 11 these seedlings 

 in field 1 appeared healthy, while the next day practically all of them 

 were thickly spotted with incipient anthracnose lesions, so numerous 

 as to cause many leaves to curl. By the next day many seedlings 

 were dying. Drainage channels from the field above led directly 

 through these rows of seedlings. Very evidently these seedlings 

 were so abundantly infected during the preceding rains that they 

 were practically blighted outright by the numerous lesions that 

 developed simultaneously. An added point of interest is that this 



