40 The Spraying of Plants. 



that black rot existed throughout the entire valley of the 

 Garonne as far as Aiguillon. In some vineyards it was so 

 well established that there appeared to be no doubt that the 

 disease had been present at least a year before its discovery 

 in I'Herault ; it was consequently impossible to determine the 

 first place of infection in France. The disease was new, and 

 at the first not very serious, so that its presence had been over- 

 looked perhaps for more than one year. None of the copper 

 compounds had been tried to check the disease, and this was 

 the most encouraging feature of the situation in the fall of 

 1887. The outcome showed that this fact might indeed give 

 rise to a hope that this new disease could be controlled. It 

 was in truth suppressed with greater despatch and with less 

 trouble than the downy mildew had been, for on August 2 of 

 the following year there was published * a letter from Prillieux 

 in which he says: " When we see two rows of grapes, one en- 

 tirely devastated, the other preserved by treatment, we must 

 feel encouraged for the future." The following week the same 

 journal published 2 another letter from Prillieux, saying : " These 

 experiments demonstrate with complete certainty, as was sus- 

 pected, but without having been positively established either 

 in America, where the disease has ravaged vineyards for years, 

 nor in France, that cupric treatment can stop the invasion of 

 black rot as well as of mildew, provided applications are made 

 early enough, and in a proper manner. The success in the 

 experimental treatments at Aiguillon in a year favorable to the 

 disease, as was proved by the complete destruction of the crop 

 on untreated plants, is a guarantee of success in the future. We 

 can now combat the black rot as effectually as the mildew." 



No other events of much importance appear to have occurred 

 in France in 1887 or 1888. The use of more dilute Bordeaux 

 mixture was not followed by such uniformly good results as 

 was hoped. Several vineyardists recommended a mixture which 

 should contain not less than 3 kilos copper sulphate in 1 hecto- 

 liter of the mixture, and it was thought advisable to make 

 it even stronger for the first application. Many were also in 

 favor of using only 2 kilos. Burning of the foliage had resulted 

 from some applications, and this led to the advice of using at 

 least equal parts by weight of quicklime and copper sulphate. 



* Jour. d'Ag. Prat. 18S3, Aug. 2, 151. 2 ma. Aug. 9. 195. 



