The Republican journal. [volume] (Belfast, Me.) 1829-current, 1918-02-28
Spraying Potatoes Pays.

the opinion that it does not pay to spray
potatoes for late blight. They claim that
when the weather conditions are such
| that the disease is severe, spraying does
not control it sufficiently to give an APP
preciabie increase in yield, also that in
seasons when the attack is light the in
crease in yield from spraying is not suffi-
Gent to cover the added cost. Conse-
quently they maintain that spraying is
Improbable at any time
That thorough spraying will control
late blight in seasons of bad infection has
been proven many times in the past, par
ticularly in Maine, and most recently in
Aroostook county in 1917. Among other
places in the county this was shown con-
clusively at Aroostook Farm where ex-
tensive experiments were conducted by
the United States Department of Agri-
culture in cooperation with the Maine
Agricultural Experiment Station.
In one block where small tests plots
sprayed with standard bordeaux mixture
were interspersed with untreated check
plots the average yield on II of the for
mer was at the rate of 1872 bushels per
acre, while that on an equal number Of
untreated plots was at the rate of l43 5
bushels per acre. This was an increase
of 37.7 bushels per acre, or more than &c
IF hardoonv ixyt,,r
In another similar block the average
yield of plots sprayed with bordeaux
bushels per acre, while that of the I'M
treated check plots in the same block
was 1743 bushels. The gain here was
e. bushels per acre or about sc per cent,
due to spraying Six applications were
made on all the above men toned sprayed
plots.
On these experimental plots spraying
ought to have been started 10 days or
weeks sooner, by the end of the first
week in July. In spite of this fact the
Yields given above indicate quite plainly
that spraying paid. Moreover, many per-
sons who saw the plots during the latter
part of the season have testified to the
sprayed portions. On all the treated
| plots the spraying was done with a trac
ton sprayer which maintained good
working pressure of at least $50 pounds
per square inch.
/ Adjoining one of the experimental
blocks was field where spraying was
begun earlier and or 9 applications were
made. 1t was planted with the same lot
of the same variety of feed, fertilized the
same and, except for. spraying, received
similar treatment in every respect. The
yield on the portion of this field immedi-
ately adjoining one of the unsprayed
check plots was 1918 bushels per acre.
Comparing this with the averages of the
unsprayed check plots mentioned above
shows gain of 1888 and 90 bushels per
acre respectively, or over Sc and So per
cent. In none of the above figures is any
account made of the extra loss resulting
from tuber rot in storage in the crop pro-
duced on the unsprayed plots
! 1917 was one of the worst blight years
in the history of Aroostook potato grow
ing The results cited above show con-
clusively that, even under the conditions
that existed, late blight can be controlled
| by grower who sets out to do the job
thoroughly. Moreover, they indicate
that it can be done at fair profit when
the cost is considered in connection with
the value of the increased yield resulting
from the treatment.
CHAS. D. WOODS, Director.