220 MANUAL OF FRUIT DISEASES 
surface of the diseased portion is smoky in color. The lesions 
are roundish or angular, and measure from one-sixteenth to 
one-eighth of an inch in diameter. Little attention has been 
given to the life-history of the pathogene. 
The disease may be controlled by the schedule advised for 
the Mycospherella leaf-spot (see page 205). 
REFERENCES ON ANGULAR LeEar-Spot 
Pammel, L. H. Spot diseases of currants and gooseberries. Iowa 
Agr. Exp. Sta. Bul. 13: 67-70. 1891. 
Pammel, L. H. Treatment of currants and cherries to prevent spot 
diseases. Experiments with currant spot diseases. Iowa Agr. 
Exp. Sta. Bul. 30: 289-291. 1895. 
AMERICAN PowbERY-MILDEW 
Caused by Spherotheca mors-uve (Schw.) B. and C. 
This is believed to be primarily a gooseberry disease both in 
Europe and in America. It may, however, cause considerable 
injury to currant bushes, as was noted in July, 1915, on black 
currants in a New York State nursery. The disease was then 
found affecting the varieties Champion, Naples and Saunders, 
while red currants near by were resistant. The trouble has 
also been reported from Ohio, Nebraska, Washington and 
California. 
The affected leaves and berries are covered with a brownish 
felt-like growth. 
Although the causal fungus, Spherotheca mors-uve, is mor- 
phologically the same as that causing gooseberry-mildew, yet 
limited observations indicate that the pathogene on the currant 
is so specialized that it refuses to infect even the most sus- 
ceptible varieties of gooseberries. Conversely, the fungus, even 
when abundant on gooseberries, is rarely found on currants 
growing in close proximity. (See Gooseberry, page 222.) 
