OBSERVATIONS ON THE VINE MILDEW. 289 



over before, the Oidium ran through its pliases of vegetation and 

 the grapes did not cease to grow. Before the storm of which I 

 speak 1 had already acquired a certainty of the fact that when 

 the leaves were frequently syringed with common water the 

 fungus grew abundantly and tlie grapes were not the more 

 diseased. It is to this protracted mode of propagation that we 

 must attribute the small influence of the malady on a great 

 number of the berries which, though almost entirely covered, 

 arrive notwithstanding at perfect maturity. 



These spontaneous recoveries deserve more attention than may 

 appear at first sight ; they may take place when some particular 

 remedy is applied, and since it seems to have succeeded, all the 

 advantage is attributed to the remedy. I have never seen these 

 recoveries at the beginning of the disease, that is to say, when 

 the berries were forming ; but when they have acquired a 

 certain size the Oidium is then contagious, and may appear two 

 or three times on the same grape without its being sensibly in- 

 convenienced, because it is superficial, and there has been no 

 primitive disease of the tissues. I am liowever exaggerating a 

 little — its harmlessness is not always so great ; when it covers 

 the grapes with a thick mycelium, it stifles the berries ; but tlien 

 they do not crack, they dry up. 



Up to the present time there are but two opinions respecting 

 the disease of vines: the one generally adopted, which attributes 

 it to tiie development of the Botrytis,* and my own, for 1 am in 

 point of fact the only person who considers the fungus as one of 

 the consequences of the disease. This divergency of opinion in- 

 duces of necessity another in the treatment of the malady with a 

 view to its cure. 



M. Duchartre, Professor of the Agronomic Institute of Ver- 

 sailles, in a report addressed to tiie Minister of Agriculture and 

 Commerce on the means of combating the eflfects of the fungus 

 which attacks the vines, said, " I am to-day happy in being able 

 to announce to you that the treatment to which the diseased vines 

 have been submitted has given excellent results, and tliat hence- 

 forth we may flatter ourselves with being able to combat it with 

 success whenever it may appear." 



The remedy employed by M. Duchartre consists in dashing 

 over the diseased vines, by help of a garden syringe pierced 



* This is probably a slip of the pen for Oidium; a true Botrytis of the 

 same section with Botrytis infestans, but far more beautiful, and highly 

 developed, and, like all the allied species prejing on the parenchym, occurs 

 in South Carolina on vine leaves. I have not, however, heard that it is 

 injurious. My specimens, which were gathered by Mr. Kaveuel, and have 

 been named B. viticnla, Berk, and Curt., occurred on Vitis astivalis, and, 

 I believe, on some other species. 



VOL. vr. ^ 



