The Delta independent., 1909-04-30
Arsenic a Dangerous
Spraying Material.

ling moth?" is the subject of a paper
written by G. P. Gillette for the bulle-
tin of the Colorado Agricultural col
lege. His report is as follows:
DR. w. P. Headden in Bulletin No.
131, of the Colorado experiment station,
has given most conclusive evidence
that many apple trees that have been
heavily sprayed for years with arsen-
ical poisons are in sick and dying
condition, or are already dead.
This malady has been going under
the names, "collar rot, " "crown rot, "
and root rot," without any well
founded assignable cause. There have
been several theories as to the possible
cause, such as seepage. alkali, land dis
ease organisms. The first two of these
troubles are probably one and the
same, namely, too much water in the
soil, and no one has been able to as
sign the trouble to definite micro
organism. 1t should be remembered,
also, that DR.. Headden's experiments
have nothing to do with trees that died
from drowning; and the writer knows,
personally, that many, at least, of the
samples of trees analyzed were from
land where seepage conditions are abb
solutely unknown.
DIR. Headden's discovery of the real
cause of this trouble has come, we be-
lieve, in time to prevent very extensive
losses from the death of orchard trees
in this manner. 1t will be folly, how
ever, for any one hereafter to spray
his orchard with arsenical preparations
more times or in greater strength than
is absolutely necessary to get good re-
suits.
Personally. l very much regret. as
does DR.. Headden, that arsenical
spraying is resulting disastrously to
any of our orchard trees; but it is
worse than useless to evade facts, and
l am thoroughly convinced that DR..
Headden has been very conservative in
his conclusions as to the extent of
damage that has already been done to
apple and pear trees where excessive
arsenical spraying has been carried on.
SYMPTOMS OF ARsENICAL POISONING.
The symptoms, in a rather advanced
stage of this disease, as described by
DR.. Headden and Mr.. Whipple. are
about as follows: Trees usually stunt
ed in growth; bark very yellow; bark
often dead and black just below the
surface of the ground the main roots
in a similar condition; leaves yellow
and maturing early; apples very abun-
dant, but small and highly colored; the
bark of the trunk and main limbs often
with vertical cracks which may or may
not give out an exudation. Trees
strongly exhibiting the above condition
one year are almost sure to be dead
the next year.
This trouble usually appears first
upon few scattered trees, and from
year to year seems to spread to others.
In any orchard where few trees are
found in the above condition the utmost
caution 10 necessary in spraying with
arsenical mixtures for the codling moth
or other insect pests.
HOW TO SPRAY
Since coming to Colorado, more than
eighteen years ago, the writer has
steadily urged the fruit growers of the
state to depend chiefly upon thorough
treatment or two just after the bios
SONS fall, and has advised not more
than one late treatm mt. While this
has now become very general rule
among Colorado apple growers. there
are still many who think If two or
three sprayings are good, more will be
better, and it is in the orchards that
have been sprayed four or five times
or more each season that most of the
mischief has been done.
Now, instead of recommending two
or three applications for the codling
moth, am fully persuaded that it is
best to recommend one, or at most,
two.
If an orchard has few trees that
show the characteristic symptoms of
as given above, or If the
trees have been heavily sprayed for
several years, / would ecommend one
spray only just as the blossoms are
about 80 per cent off. If the trees have
not been excessively sprayed, and If
for any reason the first application was
not very satisfactory, it might be ad-
visable to make a second application.
from four weeks to thirty days later,
which will be the time for the eggs Of
the first brood to begin to hatch well.
Arsenate of lead is by odds the best
noison to use. as it is least soluble in