GRAPE DISEASES 
spores on the vines that the first new 
infections of the summer spore stage 
start in the spring. 
Treatment 
Where this disease is serious enough 
to cause any amount of loss the vines 
must be protected by some fungicide. It 
has been found that the best method 
is to dust the plants with dry sulphur. 
The fungicidal value of dry sulphur rests 
largely in the vapors which are given 
off during hot weather (above 75 de- 
grees) Below this temperature the fun- 
gus does not grow well. If the vines 
are covered with a sulphur dust and 
the temperature rises above 75 degrees 
F., the sulphur is volatilized and pre- 
vents the growth of the fungus. 
The vines may be dusted either when 
dry or wet with dew. They should not, 
however, be very wet An application 
should always be made when the blossoms 
begin to open. In some sections this is suf- 
ficient; in others, a previous application 
when the vines are about six to eight 
inches long should be made. Sometimes 
three or four dustings are necessary. The 
vines should be carefully watched and 
when any signs of mildew are detected 
an application of the sulphur dust should 
be given to prevent its spread. 
Any method of application by which 
the herbaceous parts of the vine are 
completely covered with a very fine coat- 
ing of sulphur dust may be used. The 
most efficient method is by the use of 
some form of hand or Knapsack duster, 
several forms of which are good. The 
best are of European manufacture. 
Mr. A. H. Carson, Commissioner of the 
Oregon State Board of Horticulture and 
a prominent grape grower at Grants Pass, 
in a letter dated Sept. 17, 1912, gives 
the following information concerning his 
experience in regard to the control of 
powdery mildew under Oregon condi- 
tions: 
“For controlling the mildew, we use 
the best brand of fine sublimed sulphur. 
The first sulphuring is done when the 
grapes first bloom. It is important to 
sulphur at this time, as there is an in- 
visible mildew that attacks the bloom, 
and if sulphured at this time the grapes 
1125 
will set much heavier than if not sul- 
phured. The vines should again be sul- 
phured when the grapes have formed 
about the size of a BB shot. If the sea- 
son is normal, not too much rain, it will 
not be necessary to sulphur again until 
the grapes begin to show color, then a 
third sulphuring should be done. 
“No grape grower need fear the mil- 
dew if sulphur is used at the time of 
growth as I have indicated above. Sul- 
phuring the vines as I have indicated is 
a& sure preventive of the mildew, but, 
should the mildew develop among any of 
the vines before sulphuring, you cannot 
stop it on the vines that it has developed 
on, but you can prevent it spreading to 
healthy vines. The best sulphuring ma- 
chine I know of is the Torpille Vermorel, 
made in France, H. C. Shaw Co., Stock- 
ton, California, sole agents for the United 
States. The machine costs $15 f. 0. b. 
Stockton. One man with this machine 
can sulphur from 10 to 12 acres in 10 
hours. For a small vineyard, sulphur 
shaken on the vines from a gunny-sack 
will give results.” 
H. S$. JacKsSon 
Crown Gay. See under Apple Diseases. 
Rep Lear. See Miscellaneous Diseases, 
this section. 
Ripe Rot 
Glomerella rufomaculans Berk. 
Spauld. & von Schrenk 
Ripe rot has also been called bitter 
rot. The name bitter rot is, however, 
applied to another fungous disease of 
the grape. As the present name indi- 
cates the disease usually appears on the 
fruit when the latter is nearly mature, 
and under favorable conditions continues 
its development and destruction after 
the grapes are picked. It also attacks the 
leaves and stems, but is most noticeable 
and injurious on the fruit The first in- 
dication of the disease is the appearance 
of reddish-brown discolored spots which 
spread and finally extend over the whole 
fruit. The surface then becomes dotted 
with dark, slightly elevated pustules, in 
which the spores are borne. At this stage 
of development this disease is not easily 
distinguished from the early stages of 
black rot and bitter rot. The berries do 
