Corvallis gazette. [volume] (Corvallis, Benton County, Or.) 1900-1909, 1906-04-03

presence is not proof of the pres
ence of the scale it is evidence
that the vitality of the tree has
been seriously IMPAIRED by some
cause and in regions where
San Jose scale is prevalent that
cause in vast majority of in
stances is the scale.
| On the approach of winter
scales OF various ages and sizes
ma be found upon infested trees.
A very low portion especially
of the immature scales usually
perishes during the winter but at
the present writing, March 10,
practically all are still alive
We may expect, therefore, with
normal conditions for the re-
ma,nder OF the season, to witness
very decided increase in scale
infe>tation during the coming
summer.
The male scales ale not cir
cular but somewhat elongate
If one removes one of the large
circular scales the little yellow
object thereby revealed is a
mature female. Under a moder-
ate power of the microscope she
proves to be nearly circular,
yellow, sacklike with long,
slender, bristle-like mouth parts.
An examination of the male
shows him to be more elongate
and to possess the rudiments of
legs, wings, eyes, antennae, etc.
The females live and die beneath
their scales-never leaving them !;
but in April the males molt for
the last time and soon thereafter
emerge from under their scales
as minute active creatures with
fully developed wings. After
mating the males die.
In May, possibly earlier under
favorable conditions, the females
give birth to living young and
may continue to produce for six
weeks or longer. The young
are minute, light orange yellow.
active creatures with eyes, bristle-
like mouth parts, two antennae OF
feelers, and six legs. After
emerging from under~the protect
ing scale of the parent each
wanders over the surface of bark,
fruit or leaf until a suitable sit
uation is found when the legs
and antennae are folded beneath
the body, the bristle like beak is
slowly working through the out
er bark into the living tissue
beneath, from which it draws its
substance. At any time during
the sum mer mouths hundreds of
these little pests may be seen,
even with the unaided eye, as
they crawl about over the bark or
fruit of infested trees. !.
Even before the young insect
has attached itself to the bark
the section of the scale has begun.
At first it consists only of a fluffy
white mass of fine, waxy threads
which for the first day or so of
its existence cause the young
San Jose scale to appear as a
minute downy white speck on
the bark. AS these filaments
become more abundant they
become fused into a more and
more compact scale and assume a
yellowish color. Later the young
scale-insect mo,ts several times
during its growth and the fully
developed scale is thus made up
of fused wax flaments and the
several molted skins.
Each female of the over-winter
generation is capable under
favorable conditions of produc-
ing approximately one hundred
young. In the course of but one
month these reach maturity and
the females begin to produce
another generation. There are
thus produced some four or Eve
generations during the entire
season. Uuder supposedly fav-
orable conditions single females
of the later generations have been
observed to produce approximate
ly six hundred young. Basing
their estimates upon breeding
cage observations, DR.. Howard
and Mr.. Pergande have shown
thot is would he nnssihle f1nder