Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1918-03-07
SPRAYING POTATOES PAYS
This Is Shown by Cooperative Experi-
ments Conducted mt AroOstOOk
Farm in 1917.

Some potato growers have expressed
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 1t sufficiently to give an appre-
ciable increase in yield and also, that in
seasons when the attack is light the in
crease in yield from spraying is not suff-
Client 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. and
most recently in Aroostook county. Maine,
in 1917. Among other places in the county
this was shown conclusively at Aroostook
farm, where extensive experiments were
conducted by the United States Depart
ment of Agriculture. in cooperation with
the Maine Agricultural Experiment Sta
ton.
In one block where small test plots
sprayed with standard Bordeaux mixture
were interspersed with untreated check
plots. the average yield on II of the former
was at the rate Of 1912 bushels per acre,
while that on an equal number of I'M
treated plots was at the rate Of 1885 bush
els per acre. This was an increase Of 81
bushels per acre. or moro than &c per cent
in favor of Bordeaux mixture.
In another similar block the average
yield Of five plots sprayed with Bordeaux
mixture was at the rate Of nearly 237
bushels per acre. while that Of the four
untreated check plots in the same block
was 174.3 bushels. The gain here was 625
bushels per acre or about So per cent. due
to spraying Six applications were made
on all the above mentioned sprayed plots.
On these experimental plots. spraying
ought to have been started 10 days or two
weeks sooner, or 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
striking differences on sprayed and UNI
sprayed portions. On all the treated plots
the spraying was done with a traction
sprayer which maintained a good work
ing pressure Of at least $50 pounds per
! square inch.
Adjoining one OF the experimental blocks
was a field where spraying was begun
earlier and eight or nine applications were
made. 1t was planted with the same LOT
| of the same variety Of seed, fertilized the
same, and. except for spraying. received
| similar treatment in every respect. The
yield on the portion of this field imme.
diately adjoining one Of the unsprayet
check plots was 1918 bushels per acre
Comparing this with the averages Of the
unsprayed check plots mentioned above
shows a gain Of 1898 and 90 bushels pei
acre. respectively, or over Sc and SO pei
cent In none Of the above figures is any
account made of the extra loss resulting
from tuber rot in storage in the croI
produced on the unsprayed plots.
Nineteen hundred and seventeen wa.
one of the worst blight years in the his
tory Of Aroostook potato growing. TIL.
results cited above show conclusively 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 1t can b,
done at fair profit when the cost is con
sidered in connection with the value O
the increased yield resulting from tn,
treatment.
These recommendation apply particu
larly to the potato sections lying north o
q line drawn from New York to Chicago.