The Bridgeport times and evening farmer., 1918-02-26
BULLETIN SHOWS
POTATO SPRAYING
GIVES 4 PROFIT
Report That 1t Is Not Sue
cessful for Late Blight Dis
proved by Experiment.

Washington, Feb. 26.-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 it sufficiently to give an
.appreciable increase in Yield and also,
that N seasons when the attack Is
light the increase in yield from spray
ing is not sufficient to cover the added
cost. Constantly they maintain that
spraying is Improbable at any time
That thorough spraying will con-
troll late blight in seasons Of bad infec-
ton has been proven many times II
the past, and most recently in Aroos-
took County, Maine, in 1917. Among
ether places in the county this was
show conclusively at Aroostook farm
where extensive experiments were
conducted by the United States De
partment of Agriculture, in co-opera-
ton with the Maine Agricultural Elk
pertinent station.
In one block where small test plot!
sprayed with standard Bordeaux mix
ture were interspersed with untreatet
check plots, the average yield on L
Of the former was at the rate of 1871:
bushels per acre, while that on al
equal number of untreated plots wa
at the rate of 1885 bushels per acre
This was an increase CT 37.7 bushel
per acre, or more than 26 per cent. II
favor of Bordeaux mixture.
| In another similar block the aver
age yield of plots sprayed with Bor
deauX mixture was at the rate of near
\ ly 237 bushels per acre, while tina
of the untreated check plots in tn
same block was 174.3 bushels. TIL,
gain here was 62.5 bushels per acr,
or about Sc per cent, due to spraying
! Six applications were made on all tn
above mentioned sprayed plots.
On these experimental plots, spray
| ing ought to have been started 10 day
| or two weeks sooner, or by the ent
of the first week in July. In spite o
this fact, the yields given above indi
cate quite plainly that spraying paid
Moreover, many persons who saw tn
Plots during the latter part of the sea
son have testified to the striking diff
1
portions. On all the treated plots, tn
sprayer which maintained a goo
working pressure of at least Is
pounds per square inch.
Adjoining one of the experiments
blocks was a field where spraying wa
begun earlier and eight or nine appli
cations were made. 1t was plapte
with the same lot of the same Variet
CT seed, fortified the same, and, e2
cept for spraying, received simila
treatment in every respect. The yiel
on the portion of this field immediate
ly adjoining one of the unspraye
check plots was 267-2 bushels ner acr.
Comparing this with the averages {
the .unsprayed check plots mentione
above, shows a gain of 1898 and 8
bushels per acre, respectively, or owe
Sc and So per cent. In none of tn
above figures is any account made
the extra loss resulting from tuber II
in storage in the crop produced on tn
unsprayed plots.
Nineteen hundred and seVentee
was one of the worst blight years
the history of Aroostook potato Srov
| 1AlSs L AlC CoullS SlLCu CIOONS SIlO" COI
clusively that, even under the cond
lions that existed, late blight can |
controlled by a grower who sets OF
to do. the job thoroughly. Moreove
they indicate that it can be done
fair profit when the cost Is .consiC
cred in connection with the value
the increased yield resulting from Il
/ treatment.
7 These recommendations apply pa
J ticularly to the potato sections lyir
north of line drawn from New Vol
, to Chicago.