EDGERTON: GNOMONIA 597 
plants growing wild near Ithaca were inoculated, the inoculations 
being made at various places on the canes. As a result of these 
inoculations, two plants became infected with the disease. Why 
the other eight or ten inoculations did not take may possibly have 
been due to a loss of virulence, caused by growing the fungus for 
ten months. on artificial media. However the wild blackberry 
plants may be more resistant to the attacks of these forms than 
the cultivated varieties and this may have had something to do 
with the poor infection. One of the successful inoculations was 
on a wound made by cutting off the entire upper third of the plant. 
The disease followed down the stem and in a few weeks perithecia 
were produced in abundance. In the other successful inoculation, 
the pure culture of the fungus was inserted in a wound made by 
removing one of the small side branches. The disease spread in 
all directions, finally encircling the stem. The plant was not 
killed as suddenly as the original plants that were found, but died 
more gradually. Fruit set on the branches, but most of it dried 
up before it matured. Perithecia were produced on the diseased 
portion about three or four months after the inoculation. How- 
ever, these were not produced in such great abundance as they 
were on the original plants. 
The results of this study seem to show that the fungus Gxo- 
monia Rubi Rehm is a weak facultative parasite, a form that will 
grow rapidly as a saprophyte on the dead canes and will if conditions 
are suitable adapt itself to the living cane. It does not seem 
probable that it is a form that is liable to become a serious pest to 
blackberry canes, but rather one that may appear as a parasite 
only occasionally, only when the conditions are right. 
