The Lynden tribune. [volume] (Lynden, Wash.) 1908-current, 1918-07-18
SAYS APHIS WON'T BE
BACK HERE NEXT YEAR
State Expert Says Lynden Farmers
Have Little To Fear From Pest
For Several Seasons

That there will probably not be
another outbreak of aphis in the Lyn-
den district for some time. is the op-
inion of F. B. Stookey. agronomist
of the Western Washington Exper-
iment Station at Puyallup Aphis
caused untold damage this year to
the pea and oat crop locally, but the
state expert believes that farmers
have little to worry about for the
next few seasons, as far as the pest
is concerned.
Professor Stookey has prepared the
following paper on the aphis, and
gives full outline of the insects
history and habits:
"Aphis, or plant lice. have caused
farm crops thruout Western Wash
ington this year. They injure the
plant by sucking the sap, or life
blood Crops of peas, vetch, oats,
wheat and barley have been so badly
injured that in some cases they were
almost total failure. AT this station
these crops have not been so badly
damaged since 1912, when the out
break was also very severe. From
1913 until this year the damage to
these crops caused by aphis has been
almost negligible, altho each year
they have been present to some ex-
tent. Their presence on roses, apples,
pears, cherries, rutabagas, cabbage,
kale. etc. in such numbers as to
cause considerable damage is COM
mon, but such severe outbreaks on
farm crops ;.re less common.
conditions the past winter and
spring were unfavorable to the var
ious parasites which prey on aphis.
The aphis. however, being able to
propagate under such conditions,
were able to multiply without inter
ruption. A study of the life history
of the aphis and its parasites ex-
plains the reason for the outbreak
this year and their comparative scar
city in other years.
Life History. Aphis usually have
! two host plants and spend part of the
year on one pant and part on the
other. The grain aphis, for instance,
spend part of their life history on the
apple.
1.-The small, pear-shaped, soft-bod-
led aphis. or lice. pass the winter as
adults or in the egg stage. II the
winters are mild and vegetation is
abundant the adults live and eontin-
ue to multiply. Such was the case
the past winter. In the spring the
adults continue to multiply at a very
rapid rate. From the egg is Matched
what is called a stem-mother. In
about two or three weeks after the
egg matches the aphid has reached
maturity and gives birth to living
Young. the male being unnecessary
to such reproduction.
1.-The young mature in six to eight
days and continue the reproduction
at very RAPID Tdle Edeh otSi
mother may give birth to as many as
eight or more young in twenty-four
hours. and during the period OF re-
production may give birth to as many
as one hundred and fifty young
While these young are mostly wing
less. some are winged; those with
wings fly away and start new colo
MES. Being able to travel from place
to place and to multiply so rapidly, Il
is not to be wondered at that, having
+ once become well established. an en-
y tire field can be ruined in very
short time. One author states tina
if the progeny of one aphid were al
lowed to multiply without interrup
ton for one season they would GOV
or the surface Of the earth.
Toward the end of the seasol
there are produced males and fe
males. Aftey mating with the mall
the female lays eggs. which do no
hatch until the spring.
.sControl. In normal seasons TN
parasites that prey on aphis will pret
tv we'll hold them in check, but TIM