The diamond drill., 1917-08-04
SPRAYING POTATOES.
(By G. H. cOons.)

mended that potatoes be sprayed. E1-
periments running over long periods
have been run in New York and In
Vermont. The net results OF these
years OF experimentation is that
spraying is profitable farm opera
uon. The figures that reinforce this
conclusion are interesting.
A summary OF spraying expert
ments In Vermont showed an aver
age gain OF 105 bushels to the acre
In sprayed over unsprayed rows. In
not single year did the yield from
unsprayed rows equal that from the
sprayed. In New York experiments,
the l0-year average showed gain
Of 90 bushels per acre from three
sprayings and a gain OF 971z bushels
per acre from five TO seven sprayings.
These results, covering, as they do,
long periods OF time, show the results
from spraying are consistent, and
that in many cases the gain Is enor-
nous. Nor are the figures to prove
the case for Michigan lacking, al
though the experiments have not con
tinued year after year. These expert
ments fall into two groups; expert
ments performed at the experiment
station or under the direct supervis-
ion Of the experiment station. OF the
data at hand the following figures are
important.
In 1911 on the college farm field
was sprayed with Bordeaux mixture
four times, while a part was left un-
sprayed, as check. The unsprayed
portion yielded so bushels per acre,
while the sprayed portion 1l9 bushels
per acre. In 1915 a field of patotoes
in Kalamazoo county was sprayed
and strip was left in the center un
sprayed as a check. 1915, as will be
remembered, was year when late
blight was severe. The unsprayed
strip blighted to the ground while
the sprayed remained green. The
yield from sprayed was 130 bushels
of low-grade rotted stock, from the
sprayed was 26O bushels OF flrst-class
stock. The story of this spraying
experiment was written in the Mich.
igan Farmer of December 8, 1915, by
Mr.. G. W. Waid, and the picture
which accompanied this article was
reproduced from that writo-up. Hun
dreds Of passersby drove TO this field
and saw at glance the point Of the
teachings of the Agricultural college
for a decade or more,
An interesting thing about the po-
tato spraying Is that the more thor
oughly It is done, and the more fire.
quent the sprayings, the better the
disease control and the greater the
gain. Along with the increased yield
from disease control, comes the re
markable fact that Bordeaux mix
ture exerts stimulating effect upon
the foliage. To what this effect Is
due Is not clear, but the fact remains
that tops sprayed often with Bor-
deaux mixture are greener and when
are not serious. From this IL will be
seen that there is very good rea-
son for the recommendation to spray
every year, and IL makes il very man
ifest that the spraying direEted
against these diseases Is more than
a protection. since il is a beneficial
crop practice. II may well be called
a form OF crop insurance, where the
premiums are all dividends.
But this article does not merely
aim to tell again the facts that are
now well known about the effect or
Bordeaux spray Ii will be assumed
that the case is now proved that the
spray, made al home from Blue-stone
and lime. will prevent injury from
fungus diseases, late and early
blight. II will do more: II will keer
the fields green when unsprayed
fields parch and burn from that
weather-scorch known as burn
In some way, not fully understood,
copper sulphate stimulates the leaves
and prevents the burning in hot
dry weather
In some counties sprying with Par
Is Green or lead arsenate to control
bugs is regularly practiced, and az
ter the hard experience Of last year.
But such spraying while heartily to
be recommended Is only a starter and
is not the sort Of treatment under
discussion here The purpose OF this
article is 70 discuss the fact that al
though the value Of spraying haa
been demonstrated, yet II IA not at
MI "a common nrnptipo