The Hood River glacier. (Hood River, Or.) 1889-1933, 1910-05-05
CORDLEY WRITES
ON COOLING SPRAY
O.A.C. DEAN ADVISES COMBINATION
Expert Writes Glacier UphOlding Mixture
of Lime-Sulphur Solution with
ArSenate of Lead.

The Glacier has received the follow
ing letter from Dean A. B. Cordley,
of the Oregon School of Agriculture,
which will be of special and important
interest to all Hood River apple
growers just at this time:
Editor Glacier.-As most of your
readers are aware | have for the past
three seasons used the lime-sulphm
spray as a preventive of apple scab
and during that time have added to
the lime-sulphur spray arsenate of lead
at the rate of two, pounds to each
fifty gallons for the purpose of form
ing a combined spray for both scab
and codling moth. During the recent
series of Institutes which were held
in the Hood River Valley, | recon-
mended this combination, specifically
stating that it could be used without
diminishing either the insecticidal
value of the arsenate of lead OF
the fungicidal value of the lime.
sulphur. Since then, no doubt, many
of the orchardists of Hood River
have noticed the article by Professor
Melander in March number of Better
Fruit" in which he attempts to show
that such a combination is not only un.
necessary but scientifically incorrect. |
shall have a somewhat extended reply
to Professor Melander's article in the
May issue of Better Fruit" but since
this will probably not appear until
after the first codling moth spray, it
has seemed best to call attention OF
your growers to the fact that Professor
Melander's conclusion is based entirely
upon inference and the results of a
single experiment, which, as he him
self admits, was conducted under very
adverse circumstances. Professor Mel
ander infers from a certain discolora-
tion which takes place when arsenate
of lead is added to lime-sulphur, that
complete chemical decomposition takes
place with the result that neither of
| the original substances remain. This
is not at all true provided neutral or
ortho arsenate of lead be used, and is
only true to a very limited extent If
the acid arsenate be used, as has been
shown by very careful chemical invest
| igations, the results of which will be
given in the article in Better Fruit
| above referred to.
As opposed to Professor Melander's s
single experiment, | offer three year S
experience, the experience of numer-
GUS growers, not only in the Willamette
Valley, but from as far south as
Arkansas, as far north as British
Columbia and as far east as Montana,
Michigan and New York, and almost
the testimony of the Cornell Expert
ment Station which last year used the
combined spray and reported, "That
bits efficiency as an insecticide is fully
as great when used with lime-sulphur
as with Bordeaux is fully demonstrated
by the fact shown in the table that
the wormy fruit at picking time was
reduced from 25 percent to 3.3 percent
on the Bordeaux plats and to 1.3 pei
cent on the lime-sulphur plats. Pro
fessor w. M. Scott of the U. s. De
partment of Agriculture also used the
combined lime-sulphur-arsenate of lead
spray last season and concludes that
"arsenate of lead is unquestionably the
poison to use with the lime-sulphuI
spray mixture. Instead of increasing
the injurious properties o the mixture
it apparently has the opposite effect tC
some extent, and does not lose any OF
its insecticidal value by reason of the
combination.
The weight of theoretical considera.
ton, experimental evidence and orchard
practice is certainly in favor of the
combination. A. b. Cordiey'