GOOSEBERRY DISEASES 223 
The disease is far more serious in Europe than in America. 
It is a well-recognized fact that when a fungus is introduced 
into a new and favorable climate and among new varieties of 
hosts, it is liable to become more destructive. In this respect 
the gooseberry-mildew pathogene is no exception. It is now 
established in the Old World and has become a permanent 
factor in gooseberry culture. While the fungus is less virulent 
in America, yet it is one of the most serious enemies of this 
fruit. The berries are usually rendered unsalable, and some- 
times are even destroyed. The vitality of affected bushes is 
reduced, and they are more susceptible to winter-injury than 
those which remain free from mildew. 
Symptoms. 
The lower parts are first affected. The disease appears in 
May or June. In severe cases not a single berry remains free 
from the attacks of the pathogene. The leaves and young 
canes are also affected. At first there is a superficial whitish 
growth having a moldy, powdery appearance. Several spots 
may coalesce to form large patches. The leaves and tips of the 
stems may become distorted in serious cases. Affected berries 
are sometimes dwarfed. Finally the fruit may crack and decay. 
In later stages the mildew patches become buff or rusty-brown 
in color. Scattered through the felty growth, small black 
specks may be observed. 
Cause. 
The American gooseberry-mildew fungus is known as 
Spherotheca mors-uve. The small specks mentioned above 
are perithecia of the parasite. Within each of these bodies is 
found a single ascus containing eight ascospores. These 
spores remain in the perithecium during the winter, either on 
the fallen leaves or on the canes of the past season’s growth. 
Sometimes, when the leaves disintegrate, the perithecia hiber- 
nate in or on the soil. In the spring when the leaves are half 
grown, or later, the ascospores are forcibly ejected from the 
