Daily capital journal. (Salem, Oregon) 1903-1919, 1919-04-10

When they were first reported from
the Liberty district, for want Of 4
better name. Robert {. Paulus, mana
ger Of the Salem Fruit Union, called
them "eoOties.
However, after consulting with sew
eral o. A. C. authorities il was de
eided that the small insect scarcely a
sixteenth of an inch long and about the
size " hair and Of grayish black
color that had been doing damage TO
the prunes in the Liberty district was
the California pear and prune thrip.
This insect is found in the bud Just
before il blossoms. When il has done
its work, the blossom looks like it has
been frost bitten. The insect eats the
white petals. Although it has been re-
ported found from year to- year, this
Is the first time that it has really
threatened the crop or become a mat
ter of special interest.
To answer fully the hundreds Of in
quiries that arc coming in, Mr.. Paulus
has compiled from LOwther's encyclo-
paedia of horticulture, written especial
" fer the Pacific coast the following:
Pear Thrips
Distribution; The pear thrips is at
the present time very destructive in
San Francisco bay region and the larg-
or part of the Sacramento valley Of
california More recently it has been
found in destructive numbers through
out New York state and northwestern
Pensylyania.
Economic Importance: II is at the
present time the most important in.
sect pest with which the growers Of
deeiduous fruits in the sections men
toned have TO contend. On account Of
the minute size Of the insect, the rapid
ity Of its spread over larger areas, and
the snddenness Of attact in great MN
bers - completely blasting in a few
days all prospects FOR a erop--the con /
troll of this pest is matter Of eonsid |
cradle difficulty. As the insect each |
year is extending lts range of food |
plants, its capabilities for dissemna
tion are eorrespondngly increased. |
There is no reason TO believe that tho /
insect win disappear il should be re.
garded as a permanent and serious .
pest. Conservative estimates place the
damage caused by the pear thrips IN
California during the years from 1904
TO 1912 at least $G,0O0000. II is safe
10 say that the thrips in the absence
of treatment would cause an average /
yearly loss to the state of over 81 ,00O X
900.
Character Of injury: Injury to the
various fruit trees by this species is ,
caused by the feeding Of the adults on
the developing buds and yearly bios.
SONS; by the deposition of eggs into
the fruit stems, leaf stems, and newly l.
formed fruit, and by feeding Of the /
larvae in the blossoms and on the J
young fruits and foliage. On pears the Z
greater injury is produced by the /
adults which often prevent the trees ,
from blooming, while on the prunes and I
chornies the larvae frequently prevents /
q crop Of fruit from setting after the n
trees have come into full bloom, and al
80, the deposition Of the eggs into the
fruit stems Of prunes and enerries so 1
weakens the stems that much of the q
Young fruit falls. BY rasping the ten c
Ter surfaces in the developing fruit b
buds and the young fruits with their L
hardened mouth parts, the thrips rup a
.ure the skin, causing an exudation of
zap which is often followed by more
n less fermentation, especially before y
he blooming. The feeding by larvae o
m prunes after blooming causes the g
we'll known thrips "seab, while n
most Of the Scared and misshapen e
BEARS are caused by the work Of the o
ldults. b
LIFE HISTORY O
Adults y
The adults or winged form Of the "a
hrips appear on the trees about tho L
middle Of February. appearing in great
81 numbers In late February and early
iarch. q,
by the time the fruit buds have
wollen sufficiently TO separate the p
nd scales slightly at the tip the adults
orce their way within, feeding upon Al
he tendcrest portions inside the buds. oi
Eggs I'm
As soon as the first leaf surfaces or Al
ruit stems are exposed egg laying "
sually begins, depending somewhat IL
n the variety of the fruit attacked. r,
.gg laying begins the first days Of n
lareh and continues till the middle Of m