The Black Rot of Grapes. 39 



As regards the number of treatments necessary for the best 

 and most economical protection of the vine, Millardet says 1 that 

 at least two must always be made, " but the earlier appearance 

 of the disease, its greater intensity, and rapid spreading may 

 render three or even four applications necessary." They were 

 made in 1887 as follows : June 10, or some days before flower- 

 ing, July 14, and August 8. This apparently was not sufficient 

 to protect the vines fully. 



The conclusions reached by Dr. Patrigeon in his work of 

 1887 were that the price of applications of the hydrocarbonate 

 of copper dissolved in ammonia (modified eau celeste) was very 

 low ; that the formulas for the preparation of the solution are 

 remarkably simple and practicable ; that the material is equally 

 or perhaps even more efficient than any other fungicide in use ; 

 and that it is perfectly harmless to foliage. These claims for the 

 merit of the solution were indeed founded upon fact, for it has 

 been hard to decide, in regard to the comparative efficiency, 

 between the Bordeaux mixture and the ammoniacal solution of 

 the carbonate of copper, which is practically the same as the 

 modified eau celeste recommended by Dr. Patrigeon. 



The American disease of grapes commonly known as black 

 rot was first discovered in the vineyards of France in August, 

 1885. Mr. Ricard, the steward of an estate situated at the 

 gates of the small town of Ganges at the borders of 1'Herault, 

 was the first to call attention to the presence of this fungus. 2 

 He saw that his grapes turned brown, then black, while still 

 remaining upon the vine. He sent some of these diseased 

 grapes to the viticultural laboratory of I'Ecole de Montpellier, 

 where Messrs. Viala and Ravaz recognized the parasite. They 

 went to the affected vineyard, and saw that only about thirty 

 hectares in the plain of Ganges showed diseased grapes. In 

 these vineyards the harvest was reduced about one-half. 



Immediate and energetic steps were taken to exterminate the 

 fungus, but in 1886 it again appeared. The season proved to 

 be dry, however, and very little damage was done. The area 

 of distribution was nevertheless considerably extended. 



On July 25, 1887, Prillieux received diseased grapes from 

 Azen, in Lot-et-Garonne, and was directed by the minister 

 of agriculture to proceed to the infected district. He found 



i Jour. VAg. Prat. 1888, May 17, 694. 2 Ibid. June 14, 84T. 



