News and citizen. [volume] (Morrisville, Vt. ;) 1881-current, 1894-07-12
SPRAYING POTATOES.
POINTS or INTEREST FROM THE STATE
EXPERIMENT STATION.

giving directions Tor Jne use OF DOT
deaux mixture. We are satisfied af-
ter five years experience that it pays
to spray all potatoes in Vermont
with this mixture.
Our potato VINES are attacked by
two distinct blights. TheeaI blight
attacks earlier potatoes, spreading
slowly in July and August, causing
premature death OF vines, but no rot.
The late blight attacks later potatoes
in August and September, spreading
rapidly in warm, moist weather, and
is followed by rot. The early blight
is a complex trouble caused by the
attacks of insects as well as fungi. 1t
is already appearing on early pota-
toes. Being a complicated disease, it
is less perfect Y controlled by spray
ing than is the late blight. Our re-
suits last summer showed that it can
be at least partially checked by Bor-
deaux mixture. The late blight and
rot is a fungous disease, and Bor-
deaux mixture properly applied is an
almost perfect remedy. BY its use
we have invariably kept our later po-
tatoes alive through September and
have lost but very few from rot. The
result has been that our yield of later
potatoes has been more than doubled
by spraying. Every potato grower
should try it this summer, especially
on medium and late potatoes.
The formula for Bordeaux mixture
is: Five pounds copper sulphate, 5
pounds lime Unjust be fresh, not air.
slacked), so gallons Il barrel water.
Dissolve the copper sulphate in clean
wooden or brass vessel, slack the lime
in another vessel, then dilute with
water to a thin whitewash and strain
it into the copper solution. Stir thor
oughly and add water to make about
so gallons Il barreD.
The following suggestions may
prove of use:-
1. Keep the mixture clean. Chips,
Jumps of lime, ETC., in the mixture,
will clog pump or nozzles. Therefore,
thoroughly clean all vessels to begin
with. Strain all water and copper
solutions through cheese cloth unless
they are perfectly clean. Strain the
lime whitewash through some coarser
cloth or sieve and throw away all the
,dregs and Jumps.
2 To dissolve blue VitrOl. 1t may
be quickly dissolved in water by heat
ing in a brass kettle to the boiling
point, or by pouring boiling water
cover it. The most convenient way
wehave found, however, is to dissolve
in cold water by puttingit in acoarse
sack and suspending this in the top
ola tub or barrel of water. AS fast
as the heavy solution forms it settles
Z to the bottom and fresh water rises.
by using a gallon of water for each
pound of blue vitrol it will dissolve
in few hours in this way.
3. Keep q stock solution. We find
it most convenient to dissolve con-
siderable blue vitrol at time in the
above manner, and keep it on hand
in a covered barrel. We put in a
pound of vitrol for each gallon of
water, and as we wish it from time to
time we simply stir it up and dip out
as many gallons of water of the solu-
tion as we wish to use pounds of blue
,Yitrol.
4. Other convenient methods. To
avoid the trouble of weighing. the
blue vitrol may be measured out 6
pounds equals 2 querts), and the
lime added by test. This test con-
sists in pouring few drops of solu-
lion of ferro-cyanide of potassium 4
OF. in OF. water) into the mixture.
If there is not enough lime in the
mixture this solution will at once
vUlrn brick-red, but if enough lime has
been added there will be no change of
color.
8. Caution. Strong copper sulphate
solution alone will kill the leaves.
Freshly slaked lime neutralizes the
sulphate and prevents this caustic
action. If not sure that the lime is
fresh or good. or that enough is add
ed, the mixture should be tested as
described in 4, or a few plants only
should be sprayed at first to test it's
action.
6. Potato Beetles. Bordeaux mix
ture alone will not kill potato bugs.
Add Paris green when needed at rate
X pound to so gallons.
Z. When to spray. Remember that
Bordeaux mixture is a preventive,
not a cure, and the first application
should be made before the disease ap-
pears. The following dates for spray
ing potatoes are based on our expert
ence at Burlington: Early potatoes
planted April to May 3, spray about
July l, Is, August 1, and again if
needed Medium potatoes planted
May 3 to Is, spray about July Is,
Aug. 1, Is, and again if needed. Late
potatoes planted May Is or later,
spray about August 1, IA, %, and
again if needed.
8. How to apply it, The mixture
may be put on in any way so as to
cover the surface of all the leaves.
: The best way to do this is with a
Iforce pump which has good spraying
ynozzles attached. Unfortunately, but
few have these pumps. Applying
with common watering pot or with
a nail and broom or wish of haV