New YorkK AGRICULTURAL EXPERIMENT STATION. 127 
HOW DISTINGUISHED FROM OTHER CURRANT LEAF 
DISEASES. 
Among fruit growers the currant disease under consideration 
is usually known as leaf blight or sometimes as leaf spot. Since 
there are at least two other common currant leaf diseases which 
go by the same name much confusion would be avoided if fruit 
growers would follow the custom of mycologists and call this 
disease anthracnose. Mycologists apply the name anthracnose 
to diseases caused by species of fungi belonging to Gla@osporiumn, 
Colletotrichum and a few other closely related genera. 
The currant disease which is properly called leaf spot is the 
one caused by the fungus Septoria ribis Desm. This produces 
on the leaves dead, brown (or gray) spots which are usually 
circular in outline and have a dimeter of about one-eighth inch 
(See Plate I, Fig. 3). Asarule, leaf spot is readily distinguished 
from anthracnose by the size of the spots, anthracnose spots 

being much smaller—often no larger than a pin head. However, 
the spots formed by Septoria ribis on both red and black cur- 
rants, may sometimes be angular and quite small, although 
always larger than those of Glwosporium ribis. A notable exam- 
ple of this came under our observation at Milton where a large 
plantation of black currants, Ribes nigrum, was quite severely 
attacked by leaf spot as early as July 10. Since, at this date, 
Septoria ribis had shown itself only in traces on red currants in 
this locality, and the character of the spots was so much out of 
the ordinary, we were much surprised to find that the trouble 
was due to Septoria ribis. The spots were quite angular and 
scarcely more than one-third their usual size. The variety of 
currant is one said to have originated near Milton where it is 
known as the Mackey. 
The Septoria leaf spot is very common in New York and is 
usually the chief cause of the dropping of currant leaves in this 
State; but during the past season it was almost wholly absent 
from the locality where anthracnose was epidemic until about 
