34 The Spraying of Plants. 



Perfection of the Fungicides, and further Experiments in 

 their Use. 



Dr. Patrigeon tested the various methods of applying the 

 copper sulphate solutions. In 1886 he treated, in different 

 plots, the posts, the tying material, the plants themselves during 

 the winter, and the foliage. He also added 10 per cent of 

 plaster to a 1 per cent solution of copper sulphate and applied 

 this mixture with a broom. This last preparation possessed 

 some merit, as did also the application of the pure sulphate of 

 copper solution. But the Bordeaux mixture gave decidedly the 

 best results. Treating the posts, etc., with the copper solution, 

 in these experiments proved to be practically of no value. 



Prillieux also mentions l a case in which the Bordeaux mixture 

 again gave the best results. Professor Fasquelle, of Jura, ap- 

 plied a 4 per cent solution of copper sulphate to potatoes, and the 

 foliage was plainly injured. Bordeaux mixture, containing an 

 equal amount of copper, w r as used at the same time and no inju- 

 rious effects could be perceived in consequence of the treatment. 



The difficulty of applying the Bordeaux mixture when made 

 according to Millardet's formula induced several vineyardists to 

 vary the proportions considerably, and the general impression 

 at the close of the year 1886 seemed to be that there was no 

 necessity for using so much copper or lime to obtain equally good 

 results as followed the use of the original formula. This ques- 

 tion is not entirely settled even at the present day, and it is very 

 probable that some diseases require the use of more copper than 

 others, some being successfully treated with very small amounts. 



It was early in 1887 that the idea was first advanced of using 

 a stock solution for the making of Bordeaux mixture. 2 A cer- 

 tain amount of copper sulphate is dissolved in a given quantity 

 of water, and any desired amount of the salt can be obtained 

 by taking out the amount of water which holds it in solution. 

 The practice is now also in use, to a limited extent, for meas- 

 uring the lime. 



The necessity of adding lime to the copper sulphate solution 

 was not generally conceded. 3 Vautier made comparative tests 



i Jour. VAg. Prat. 1886, Dec. 16, 886. 



8 Eicaud, J., Jour. d'Ag. Prat. 1887, Jan. 20, 90. 



s Vigne Americaine, 1886, Sept. 290 et seq. 



