se . SECTION OF VEGETABLE PATHOLOGY. 827 
time was not convinced of their identity, although the close similar- 
_ ity of the pyenidial spores of Phyllosticta labruscee with those of 
Phoma uvicola was, of course, observed. 
Special attention has been directed to this subject during the past 
summer, and, as the result of extended field observations, I have been 
forced to conclude that the grape-leaf spot fungus and the fungus of 
black-rot of grapes isone and the same. In France the Phyllosticta 
labrusccee has been observed only in those vineyards affected with 
black-rot, and the same holds true for the United States. Wherever 
the Phyllosticta occurs it is in regions where black-rot‘prevails. In 
California, where the latter disease has not yet pepeaad: no signs of 
the fungus upon the leaves of the vines was discovered. 
The brown spots upon the leaves figured and described in my re- 
port on the Fungus Diseases of the Vine* must, then, be regarded as 
simply the manifestation of the black-rot on the foliage. 
The fact of the identity of the leaf form with that occurring upon 
the berries is especially important in connection with the question of 
treatment, for black-rot, like the downy mildew, must be treated 
preventively. Asa rule, the black-rot fungus first attacks the leaves 
some days and often a week or two before the berries are affected. 
It may sometimes be observed on the foliage even before the vines 
have bloomed. 
By watching the foliage the vineyardist may be warned of the 
presence of this dreaded parasite in good season, and upon the first 
signs of its manifestations upon the leaves he ought to begin the ap- 
plication of remedies or preventives in order to protect the fruit. 
- Evidence is accumulating that the sulphate of copper compounds 
ossess some value in checking this disease. We have been assured 
y some experimenters that there was a very decided improvement 
in respect to black-rot in vineyards treated with these preparations 
compared with those not treated. In France, also, similar results 
have been reported. M. Prillieux, in a communication addressed to 
the French minister of agriculture, says : 
It seems that treatments with the salts of copper will very economically replace 
the difficult and costly method of collecting and destroying the leaves affected by 
black-rot. M. Frechou has been assured by his laboratory experiments, carried 
on at Nerac, the results of which will finally be made public, that the slightest 
trace of sulphate of copper is sufficient fo render impossible the germination of the 
spores of Phoma uvicola as well as those of Peronospora, and on the other side, the 
slight injury caused by black-rot in the vailey of Herault upon vines treated by eau 
celeste or Bordeattx mixture for the downy mildew ought to afford some hopes of 
success in preventing the appearance of black-rot upon the berries and its disas- 
trous consequences, by destroying it at its first appearance upon the leaves by means 
of the same remedies, the efficacy of which is recognized for combating the downy 
mildew. It is possible therefore, without increase of labor, to protect the vines from 
both diseases by the same treatment. 
The hopes that by a proper use of sulphate of copper compounds 
we may find a successful treatment for black-rot certainly justify 
further careful experiments in their use. 
* Bull. 2, Bot. Division, p. 40, Plate VII, figs. c, d, e. 
