The Emmett index. [volume] (Emmett, Idaho) 1893-1925, 1908-05-14
THE LIME. SULPHUR SPRAY.
Good Preventive for Apple Scab and
Less Harmful Than Some.

A. b. Cordley. Entomologst, Oregon Experimen
Station. Corvallis.
The serious results in the form o
Bordeaux Injury" which often follow
applications of Bordeaux mixture rem
der ii almost imperative that some
means be found OF reducing this injury
! or that some spray be discovered which
may be used as substitute for Dor.
deaux.
For the past two or three years have
observed, after winter spraying apple
and pear trees with lime-sulphur solu.
tons, for San Jose scale, that the fruit
upon the sprayed trees was less "scab.
by than that upon unsprayed trees.
Upon two different occasions this winter
application was delayed until the BIOS
SONS were about to open and while the
spray, which was applied at the full
strength, did considerable injury at the
time, its decidedly beneficial effects
were noticeable when the fruit was
gathered. However the generally good
results which follow winter applica-
tions OF lime-sulphur are now well
| lJllt vi buO WOrk TO-
quires no further comment.
Nevertheless, these observations sug.
gested TO me the probability that lime.
sui bur solution might be used as
! substitute for Bordeaux mixture for
summer applications and during the
past year have so used it upon vari-
GUS plants for various purposes.
| 1t is not proposed at this time to go
at all into detail regarding these ex-
periments--I wish only to call atten-
tion to some of the results obtained
which show conclusiyely that lime
sulphur solutions may be used as
summer spray without injury to foliage
and also point strongly to the probable
ity that by its use apple scab may be
effectually controlled without danger OF
spray injury to the frnit.
Sufficient work has not been done to
justify the statement that lime-sulphur
is equal to Bordeaux as a preventive OF
this disease but the results OF the single
seasons work point go strongly to this
conclusion that | feel justified in call
ing attention to them, that growers
who have suffered loss from Bordeaux
injury, and others who are interested,
may make comparative tests Of the two |
sprays the coming season.
In carrying out the work the past |
season it became necessary first of all |
to determine how strong a solution
could be used without injury to the
foliage. This, again, made it necessary
to adopt some method of "staDdardiz-
ing" the spray. After considerable
work we adopted what may be termed
the ''stock solution" method of prepar-
ing the spray and adopted as stand
ard for the work "stock solution"
having specific gravity OF 1.27. (For
determining the specific gravity of the
solution while at work in the field we
have found the specific gravity hydro
meter a very convenient instrument.
1t is cheap, simple and convenient,
and we would recommend every grower
who expects to use lime sulphur as
summer spray to obtain one.)
This solution, similar to the Rex,
Niagara and Phoenix lime-sulphur
sprays upon the market, any OF which
would undoubtedly do as we'll, is of
clear, dark amber color, is without sed-
ment, and as stated above had spe-
,iic gravity OF 1.27. Analysis showed
that each gallon contained in solution
23S pounds of sulphur.
During the season of 1907 these !
stock solutions" of lime-sulphur were !
lsed vsriously diluted upon the apple,
bear, peach, plum, prune, ounce,
herry. grape, potatoes and celery.
The results obtained indicated that
ime-sulphur sprays produced by d.
uting l gallon of the stock solution
With 10 gallons of water may be safely
lsed upon all of the above named
,lants, with the exception of the peach,
nless it may be early in the spring, :
Ghen very slight injury was produced.
ior use upon the peach each gallon of
olution should be diluted with at least
0 gallons of water.
For the experiments with apple scab
block Of 400 Yellow Newtown trees
,ere selected, because this variety is
articularly susceptible to this disease
nd because this block was known to
9 badly infested.
The entire orchard was sprayed with
me- sulphur for San Jose scale late
! February. The orchard was then
ivided into two plats. One plat was
prayed with Bordeaux mixture on
pirl 20, May 8 and May II. The
her plat was sprayed on the same
ates with lime,sulphur solution d.
tied LIB. Unsprayed trees were left
checks in each plat.
At picking time the fruit was care
lily gathered, examined and separated
to three grades to show per cent of
nit absolutely free from scab, slightly
abby and badly scabbed. 1t was
EN- regarded to show per cent of fruit
jnred by spray.
The summing of results lie shown
aphically in the following table.
,lumn marked A shows per cent Of
nit free from scab; b, that showing
ly small scab spots; @, that badly
sbbed and unmarketable; d shows
ray injury.
A B @ d
1sprayed -. 1919 1871 51.S
49,. .49.1 1914 1915 3l.9
1913 1873 5.3 o
t. ,,,,,af he ray,ar, ha,aJ ~,