4 
New York AgqgricutturaL Exprerment STatIon. 718 
in the summer of 1884 both on leaves and twigs of the Napoleon 
pear, and was seen on both sides of the leaves. At Rosendale it 
was especially injurious to the Jacob and Larsmesse varieties and 
less injurious to the Duchesse d’ Angouléme, Ulriksdals, Sylt and | 
Kanel varieties. 
It is also stated that the occurrence of the fungus onthe leaf — 
was first noticed by Libert in France as Helminthosporvwm 
Pyrorum and was described in 1840 by J. Desmazieres, who 
afterwards identified it with Wallroth’s Cladosporiwm dendrite- 
cwm. Undoubtedly the same fungus is included by H. T. Bonor- 
den in his Abdildung, Tafel LV, fig. 94. Henceforth the apple- 
scab fungus and the pear-scab fungus were included in one species 
until L. Fuckel, in 1869, separated them as distinct species. He 
called the pear-scab fungus /. pyrinwm. 
The fungus on the pear fruit was first noticed by J. Peyl in 
Bohemia in 1864 as Cladosporium polymorphum. P. Sorauer 
described it more fully in a communication on this subject to the 
Society of Natural Sciences in Breslau. E. Prillieux presented 
the same subject before the French Academy in Paris, November 
12, 1877, and also before the French Botanical Society, January 
95, 1878. 
Like the apple-scab fungus, the pear-scab fungus. sends its 
mycelium only among the superficial cells of the affected plant 
tissue. The conidiaphores are knotted in certain places and the 
conidia are pointed at both ends. The conidia germinate readily 
in water. The only preventive measuresuggested consists in not 
propagating from the wood of diseased trees. 
16. Evans, W. H. Handbook of Experiment Station Work, 
U.S. Office of Experiment Stations, Washington, D. C., 1893, 
p. 245, states that it requires.the same preventive treatment as 
apple scab, namely (p. 18): Bordeaux mixture, ammoniacal 
carbonate of copper, or modified eau celeste, after the leaves come 
out, and copper sulphate solution, one pound to ten gallons of 
water, before the leaves appear. Average cost need not exceed 
thirty to forty cents per tree. 
17. Faircuitp, D.G. See Galloway and Fairchild, No. 23, 
and Rusk, J. M., No. 41. 
18. Farrow, W.G. Provisional Host Index of Fungi of the 
United States, p.40. Gives the following synonyms of Musi 
90 
