CURRANT DISEASES 221 
REFERENCES ON AMERICAN PowbERY-MILDEW 
Anonymous. American gooseberry-mildew on red currant bushes. 
Gard. Chron. 3: 50: 473. 1911. 
Stewart, V. B. Mildew on black currants. Phytopath. 5: 349. 
1915. 
ARMILLARIA Root-Rot 
Caused by Armillaria mellea (Fries) Quel. 
Among the many plants affected by the Armillaria root-rot 
is the currant. Severe injury is reported from the Pacific 
Northwest. Symptoms, cause and control are discussed under 
Apple, page 96. 
heats 
Fomes Root-Rotr 
Caused by Fomes Ribis (Schum.) Fr. 
This is a root disease which has been observed in New York 
and Minnesota. It probably occurs elsewhere in the United 
States, since it affects sassafras as well as currants. The 
fungus Fomes Ribis produces its fruiting bodies around the 
base of the bush. These are tough, woody, thin, rough, brown- 
ish punks, and measure one to two by two to six inches. The 
diseased roots are abnormally dark, and finally are killed. The 
destruction of affected plants is advised. 
SILVER-LEAF 
Caused by Stereum purpureum Fries 
This disease, which is by far the most common on the plum, 
is sometimes found on the currant. As yet no considerable 
injury is reported on the latter host. (See Plum, page 368.) 
