Mar. 15, 1924 
Currant Cane Blight Fungus on Other Hosts 
839 
In the fall of that year one of the writers, during a collecting trip 
through the currant-growing regions of New York, picked from a horse- 
chestnut tree (Aesculus hippocastanum) growing on a lawn between 
Milton and Marlborough, a dozen or more mature, apparently healthy 
fruits. Not more than 20 feet from the tree was a good sized currant 
patch in which cane blight was abundant. The fruits were collected, 
however, with the expectation that a nonchromogenic fungus of this type 
would develop, as one had been repeatedly secured on several successive 
years from Aesculus fruits collected in the District of Columbia. The 
fruits from New York were taken to Washington and placed in a moist 
chamber for several weeks, when they became covered with the pycnidia 
typical of Botryosphaeria ribis. Single spore cultures made from this 
material showed, however, the chromogenesis hitherto associated only 
with the currant parasite. Repeated comparative cultures were made 
and the horse-chestnut fungus proved to be indistinguishable from the 
known parasite from currant. 
Late in December of that year 24 healthy 3-year-old currants of 
the Wilder and Red Dutch varieties were secured from northern New 
York and planted in a greenhouse at Arlington Experiment Farm, Ross- 
lyn, Va. When the plants had,reached the stage most favorable for in¬ 
fection, 7 one-third of them, about 30 in all, were inoculated with the 
horse-chestnut fungus, an equal number with the parasite from currant, 
and the remainder were maintained as controls, that is, were wounded 
with a sterile knife but not inoculated. 
The results were conclusive. Nineteen of the 30 inoculations with 
the fungus from horse-chestnut developed the typical cane blight and were 
dead by the middle of May. Only 16 of the twigs inoculated with the 
fungus from currant developed the disease, but this difference is no doubt 
accidental, as the percentage of infection is as high as that usually secured 
in our previous work out of doors. None of the control plants became 
diseased. Single spore cultures from the pycnospores which matured 
later on the dead limbs showed that the chromogenic fungus was present 
in every case. All the plants which had been inoculated with the horse- 
chestnut fungus were transplanted during the latter part of June to a 
shaded place isolated from any other currants. 
OCCURRENCE OF THE CURRANT CANE BLIGHT FUNGUS ON ROSE 
In October, 1922, diseased canes from a plant of Rosa setipoda growing 
in the rose garden at the Bell Station, Maryland, were referred by the 
Federal Horticultural Board to one of the writers for identification of the 
fungus present. Microscopical examination showed that pycnidia of the 
Dothiorella type were fruiting on the stems, which were severely cankered. 
In cultures on com meal chromogenesis similar to that associated with 
the cane blight fungus was evident after about 24 hours. Single pycno- 
spore cultures were likewise chromogenic. This was the only observation 
of the disease in 1922, but late in March, 1923, a few discolored areas were 
found on the canes of three large plants, one of which was the Rosa setip¬ 
oda plant from which the first collection was made. Pycnidia, bearing 
pycnospores similar to those present on the October material, were dis¬ 
tributed over the lesions and from these the chromogen was again 
isolated. 
7 Grossenbachrr, J. G., and Duggar, B. M. op. cit,, p. 137. 
