. Bulletin of the Department of Agriculture. Agriculture; Agriculture. ANTHEAClSrOSE OF CUCURBITS. 31 conditions is not clear, unless the rains of July 12, 16, and 19 served to render conspicuous the incipient centers already existent. We have then, on August 1, 20 centers in field 1 and 13 in field 2, none of which were showing much secondary infection. The further observation of anthracnose occurrence in fields 3, 4, and 5 was inter-. Fig. 12.—Diagram showing the weather conditions at Madison, Wis., during the summer of 1916. The curve represents the daily mean temperatures; the dotted
. Bulletin of the Department of Agriculture. Agriculture; Agriculture. ANTHEAClSrOSE OF CUCURBITS. 31 conditions is not clear, unless the rains of July 12, 16, and 19 served to render conspicuous the incipient centers already existent. We have then, on August 1, 20 centers in field 1 and 13 in field 2, none of which were showing much secondary infection. The further observation of anthracnose occurrence in fields 3, 4, and 5 was inter-. Fig. 12.—Diagram showing the weather conditions at Madison, Wis., during the summer of 1916. The curve represents the daily mean temperatures; the dotted line, the approximate optimum for the fungus; the black columns, the rainfall. fered with by the removal of plants in connection with a mosaic con- trol experiment. The data presented above, as well as results that were obtained later on these fields, are summarized in Table III. Table III.—Anthracnose in fields at Madison, Wis., in 1916. Date first noted. Progress of disease. Field. Date. Number of centers. Date. Number of centers. Date. Number of centers. No. 1 July 19 July 20 July 21 July 22 ...do July 27 ...do July 21 July 22 ...do .... 15 5 1 1 1 1 Aug. 3 Aug. 1 July 26 20 13 5 Aug. 15 Aug. 14 Aug. 11 Aug. 18 ...do 46 No. 2 30 No. 3 12 No. 4 6 No. 5 10 No. 19 Aug. 24 Aug. 24 Aug. 30 2 The slowness of spread of the disease up to the first week in August may be in part explained by the extremely hot, dry weather of July, with no heavy rains after July 20. Reference to the weather chart will show that the daily mean temperatures during the latter part of July were well above the optimum (75° F.) for this fungus. Edger-. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original United States. Dept. of Agriculture. [Washington, D. C. ?] : The Dept. : Supt. of Docs. , G. P. O.
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