Graham guardian., 1914-02-27
SPRAY FRUIT TREES
San Jose Scale a Dangerous
Pest to Deciduous Fruit
Of Valley

.llN'I b'EIIdi "" eloHihk WiLIlIn we
j. rigaIed district, between solomon
|Nile and Pima. Among other things
Of comparatively little importance,
the worst deciduous fruit pest in the
United States, San Jose scale was
found TO he doing a &l>at deal of
damage. ln some cases many of
the trees were in a dead, or dying,
condition, the owner thinking that
the trees we're dying from the dis
ease called root rot, for the scale is
so small that it goes unobserved in
many cases.
Further inspection has shown that
there is g worse infestation than was
at first supposed. The hist ry OF
this pest shows that should nothing
be done TO control the San Jose scale
it will. in time, kill all fruit trees in
the valley, or render them incapable
of producing fruit.
The State Agricultural or Horti-
cultural Commission, under the di
rection of DR.. A. w. morrill,, is III.
recting a campaign against this pest.
For this reason, the assistant OF the
above state depal tneDt ms ju,l
visited the valley. The object of
his visit was to give the fruit grow
ers the best possible advice at hand
as to means and methods of contro
If, however, the fruit grower does
not take hold of the proposition and
attempt to control The scale, il is
the duty of the department to,see
that this work is done Al orchards
that are not voluntarily cal ed for
by the owner, will have to be sprayed
at State expense and reimburse
ment secured to the State by court
action according to law. With tn
returns per tree which have bseH.
obtained repeatedly in this neighhor-
hood. the trees dre far 100 va uabie
TO hesitate about this treatment, |.
peop!e, are interested in makinI
money by growing good, clean trui! /,
they may obtain valuable iniorma
ton from Mr.. Wixom, the State in
spector in this district.
The San Jose scale is a sucking
insect that infests practically al.
deciduous fruit trees. The young
are minute, yellow, lice-Eke crea-
lures. which are barely visible to
the unaided eye. After crawling
about a few hours, they pierce, the
bark with their slender beak and
begin to suck its juices. A waxy
covering then begins to develop and
this soon completely covers the in.
sect, forming a scale-Iike shield
Females remain stationary for life,
while males, upon reaching maturi-
ty, emerge and, are able to fly.
The scale, when fully developed,
is about the size of a pin head, cir
cular in outline, and somewhat con
vex, with a nipple-like prominence
in the center. The male scale is
somewhat elongated, with the nipple
at one end. "A few scale scat tered
over the tree cannot be seen with
out close scrutiny, but when the
infestation is bad, the bark has. a
greasy. ash-grey appearance, which
may be recognized some distance
away. Scratching the bark with
the finger nail, or knife, reveals 4
yellowish, oily fluid, and slicing off
a thin layer of bark underneath the
scales, discloses a reddish or ,purplish
discoloration. 1t may be most
readily detected on the fruit, which
becomes spotted with small red
circles, in the center of which are
located grayish or black scale easily
rubbed off, leaving a pale green or
white center. Usually the fruit is
not attacked until the tree il badly
infested.
Young trees may be killed in two
or three years. and old trees must
be sprayed annually to keep them
under control. ...
So insidious is the attack of this
pest that it has killed many thou
sands of trees before the owners
suspected its presence. 1t has been
estimated that San Jose scale causes
a loss of over twenty per cent, or
over thirty million dollars, to the
fruit growers in the United States
each year.
Spraying with a soluble oil in
secticide, or with lime-suIphur soIu-
ton, is necessary, in order to pre-
vent the complete destruction of the
infested orchards in this valley and
to hinder the pest from spreading
to uninfested orchards. This spray
ing should be done before the trees
start to grow in the spring. for to
kill the scale substance must be
used strong enough to damage grow
ing trees. 1t is. therefore, necessary
to take steps Immediately if any
good is to be done this spring.
The material which fruit growers
are advised to use is concentrated
lime.sulphur solution. This insecti-
eide, when diluted and ready to ap-
ply, will cost between twenty-five
and thirty cents per tree on the
average. Home. made lime sulphur