90 The Spraying of Plants. 



is inefficient, and the burial of the vineyard debris and subse- 

 quent non-culture, which are of avail against the phonia, are 

 useless here. When atmospheric conditions favor the develop- 

 ment of this pest, it spreads like a prairie fire. I have seen the 

 foliage on ten thousand vines completely blasted by mildew 

 within three days after its appearance. Our only defense 

 against peronospora will be in constitutional, prophylactic 

 treatment." 



The above review was made by one of the most intelligent 

 vineyardists in the country. It shows how comparatively help- 

 less grape growers were in controlling fungous diseases, although 

 Colonel Pearson himself had obtained good results. In the trial 

 of chemicals of which he speaks, many articles must have been 

 tested, but apparently none proved of value. In 1880, however, 

 another experimenter appears to have been more fortunate : * 

 "A writer in the California Horticulturist speaks of the success 

 of the application of sulphate of copper for mildew on rose 

 bushes, using one-half ounce to a pail of w r ater." But this note 

 did not attract any particular attention, in which respect it 

 resembles a similar one which appeared in an English journal 

 in 1861 (see page 17). 



During 1884 a substitute for Paris green was mentioned in 

 the Country Gentleman. 2 Although its use as an insecticide 

 was advised in later years, a similar preparation was also 

 thoroughly tested in regard to its fungicidal value. It was 

 made by dissolving 



Copperas 1 pound. 



Water. 4 gallons. 



When dissolved add to this solution 



Slaked lime I pound. 



The Americans were thus hovering about the truth, but they 

 did not quite discern it. The discovery was made by the French, 

 and much of the preliminary work necessary to the develop- 

 ment of this new idea was also done by them. 



The first formula for the manufacture of a fungicide that 

 was borrowed from the French was for making the material 

 which was later known as the Bordeaux mixture. It was pub- 



Coun.try Gentleman, 1880, April 22, 262. 2 Ibid. 1884, July IT, 59T. 



