GRAPE DISEASES 261 
but it neither blackens nor shrivels into prominent ridges as in 
the case of black-rot. 
Cankers are formed on the peduncles. These are brownish, 
depressed areas which may enlarge continuously until the part 
is girdled. This results in a withering of the berry, as already 
noted. 
Cause. 
The causal fungus is referred to as Coniothyrium diplodiella. 
It is claimed by certain French authorities that at least one other 
form (sexual) exists in that country, and therefore the proper 
name should be Charrina diplodiella. 
The mycelium of the fungus is abundant in the lesions, 
particularly those on the berries. Sometimes the seeds are 
affected. In the peduncles the mycelium causes the death of 
the tissues as a result of which the berries wither. About the 
time grapes begin to ripen pycnidia are produced. These arise 
as a result of a special growth of the mycelium; a cushion is 
developed in which a cavity bearing spores is finally formed. 
These fruiting bodies lie beneath the cuticle until maturity, 
when they burst forth, first appearing as shining, rosy 
points, then white and ultimately brown in color. Although 
perithecia have been reported in France, they are unknown in 
America. 
Control. 
It is doubtful whether special treatment for white-rot is 
ever necessary. The disease should be controlled by the black- 
rot spray-schedule; at least there is nothing to indicate the 
contrary. 
REFERENCES 
Quaintance, A. L., and Shear, C. L. Insect and fungous enemies of 
the grape east of the Rocky Mountains. White-rot. U.S. Agr. 
Dept. Farmers’ Bul. 284: 36. 1907. 
Seribner, F. L. White rot. U.S. Agr. Comm. Rept. 1887 : 325-326. 
1888. ; 
