GRAPE DISEASES 235 
in the leaves, canes and other attacked organs. Soon there 
follows the development of fruit-bodies, the pycnidia. The 
mycelium forms a gnarl just beneath the epidermis, and in a 
few hours a crop of pycnospores is matured. These are 
imbedded in a mass of gelatinous matter, and when moistened 
a marked swelling of the mass occurs and the pycnospores are 
forced out in a coil. They are subsequently scattered to other 
leaves, fruits and woody parts, where new lesions are developed. 
This process is repeated many times through the summer. 
With the advent of autumn the fungus ceases vegetative ac- 
tivities and prepares for winter. Some of the pycnidia live 
over until spring, as already stated. In other cases, generally 
in August, sporeless pycnidia appear on mummies; in place of 
spores the cavity of this body is filled with a whitish cellular 
tissue. In such a state the structure is sometimes referred to 
as a pycnosclerotium, and as such the fungus passes the winter. 
In the spring the solid interior of the pycnosclerotium is re- 
placed by asci which eject most of their spores in June. Some 
of the ascospores are not discharged until later, and may even 
be found as late as October. With two kinds of spores always 
present in a vineyard of affected plants it is not difficult to 
understand how unsprayed, susceptible varieties may be ruined 
in a favorable season of considerable rain. 
Control. 
Black-rot has long been kept in check by the application 
of bordeaux mixture. It is essential to successful protection 
of the vines that the spraying should be made before rains and 
that the work be thoroughly done. Apply bordeaux mixture 
5-5-50 as follows: (1) when the second or third leaf is showing ; 
(2) before the blossoms open; (3) after the blossoms~have 
fallen; (4) about 10to 14 days later; (5) again in 10 to 14 days. 
In spraying and in the employment of other measures against 
black-rot the following matters should be kept clearly in 
mind : 
