Fungous Dishasks of Plants, PnArn Yi;i.lows 139 



exhaustively Mid prepared a map for the lithos^raj-ilurs showing the dis- 

 tribution of the potato rot. 'Ihc first from the figures of the Tenth 

 Census, the second from 2000 returns to a circular sent out by the Section 

 at my suggestion. 



In 1886 Smith published also a " Partial list of parasitic dis- 

 eases observed in Michigan," '' chiefly in Ionia, Clinton, Ingham, 

 and Washtenaw Counties. Arthur compiled and published a 

 similar list of " Plant diseases. Observed at Geneva, New York." '° 



Smith's translation of Appendix C, " Prevention of mildew — 

 results of experiments with various fungicides in French and 

 Italian vineyards in 1885," was very important. In it was pre- 

 sented Pierre Alexis Millardet's own description of his celebrated 

 discovery of Bordeaux mixture which was soon thereafter intro- 

 duced into the United States and from which sprang "probably 

 one of the most remarkable series of investigations and experi- 

 ments ever witnessed in this or in any other country. Fungicides 

 of many kinds," Galloway has said,^' " w^ere proposed and tested 

 on a large scale, and extensive lines of investigation were in- 

 augurated not only by the Department of Agriculture, but also by 

 private individuals in various parts of the country." 



Millardet^^^ had studied botany with Wilhelm Hofmeister at 

 Heidelberg and with DeBary at Freiburg, and, while like DeBary 

 he obtained a doctorate of medicine, he chose to teach botany and 

 was a professor at Bordeaux when he and his co-workers made 

 their famous discovery. While studying Perojiospora viticola in 

 the " hope of discovering a weak point in its development which 

 might enable [them] to become master of it," ^^ he chanced to 

 notice that a mixture of copper sulphate and lime, at first sprinkled 

 on grapevines along a road to discourage the stealing of fruit, had 

 a prophylactic effect against the fungus of the downy mildew\ It 

 had been known for some time that copper in various forms 

 destroyed fungous spores. But this chance observation, made in 

 October 1882, in a vineyard of St. Julian in Medoc, was followed 

 by extensive experimental investigation, and by 1886 the United 



^'■Report of the Mycological Section, Report for 1886, op. cit., 133. 

 ^"Idem, 132. 



^' B. T. Galloway, Progress in the treatment of plant diseases in the United States, 

 Yearbook of the U. S. Dep't of Agric. for 1899: 195. 



"H. H. Whetzel, Outline hist, of phytopathology, op. cit., 63-64. 

 '"'Appendix C, op. cit., 9: 94-96. See also, idem, 10: 97; 12: 108-112. 



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