Smyrna times., 1925-04-08
SPRAYING GRAPE VINEYARDS TO
CONTROL SPREAD BLACK ROT
DEMONSTRATIONS BY COUNTY
AGENT SHOWS GOOD RESULTS
Grape Industry Growing in Such Pro-
portions as to Make 1t Important to
Combat Disease in Nick of Time

Combat Disease in Nick of Time
Results obtained from the grape
spraying Unconstitutional work which
has been conducted in Kent County
for the past four years under the di-
rection of the Department of Plant
Pathology of the University of Del
aware, have proven cOnclusively that
the black rot it spread from year to
year by the carrying over of the fun
gus on the wood that is used in tying
up each spring. 1t is therefore of
vital Importance that this new growth
be thoroughly covered with the BOr-
deaux spray at the time the black
rot spores are shooting from the last
years infected canes.
In studying the various dates for
applying this spray to control the
black rot it has been found that the
first application should go on when
the new growth is from one-half to
three-fOurths of an inch in length.
This first spray is known as the de-
layed dormant application and should
be somewhat stronger than the sum-
mer sprays. The Department of Plant
Pathology recommends the 6-10-50
formula for the first Bordeaux spray
which means 6 pounds of bluestone,
10 pounds of hydrated or stone lime,
and so gallons of water.
A second (summer) spray should
be given when the vine growth is 5
to Z inches, using a $3.50 or 4-5-5O.
The later strength to be used by low
pressure traction outfits. For orchard
outfits carrying $50 to 300 pounds
pressure $3.50 is recommended.
A third spray should be given just
before blOssOming using $3.50. These
three preblossOm sprays are worth a
dozen after blossom sprays.
A fourth spray should be given di-
rectly after blOssoming using the
$3.50 formula to which one and one
half pounds of powdered arsenate of
lead is added. If rose bugs are bad
a quart of cheap molasses should be
added.
A fifth spray, the same as the
grapes are the size of peas. This
program is adequate for black rot
brown rot and grape insects except
fourth, should be given when the
the leaf hopper, which requires Black
Leaf 40, or what is known as 400
nicotine sulphate, at the rate of one
half pint to so gallons.
Care Should be Taken in Pruning
From the time the Commercial
grape industry was first started il
Delaware it has been the custom Of
many nurserymen to go into these
grape districts and gather the prun
ings which are used to furnish Other
farmers with cuttings or with roots
In following this practice apparently
no attention has been given by these
nurSerymen to the great danger in
volved in the distribution of the blacl
rot which causes thousands of dollar
in damaged grapes each year in thi
State.
In the grape spraying demoustra
|
the grape districts of Dover and Wy
oming during the past four or fv
years by DR.. T. +. Manns of the Uni
versity Of Delaware, it has been prov
en- conclusively that the vine infec
tion is a much greater agency il
spreading such diseases as black rot
brown rot and anthrOcnose than i
the infection on the fruit. These dc
structive diseases are carried owe
from one year to the next on the ol
canes of the previous season, and fO
this reason all prunings from infest
ed vineyards should be destroyed ir
stead of being used for prOpagatiO
t purposes.
e The practice of nurserymen gOin
into these grape producing areas an
taking cuttings indiscriminately frol
4 vineyards that are heavily infeste
with black rot and anthrOcnOse shou'
therefore be severely cOndemne
~ There should be either a state reguli
2 ton to prevent such practices, or
i law by which all diseased nursel
e stock could be condemned as untt f
planting.
Distribution of Diseased Grapes
During the past few weeks the q
tention of the members of the Ag1
cultural Extension Department h
!. been called to the distribution Of d
'1' eased grape cuttings by nurserym'
as practically all the prunings fro
some Of the larger vineyards we
collected by these people for the pl
pose of using them to sell as cuttin
or roots. Every grape grower shor
- be sufficiently interested in the co
plete eradication of these diseases
such an extent that he would ref
to have his vine prunings used