Oregon State Agriculthral College
Oregon :xperiment Station
J.T. Jardine, Director
Cir'ular of Information No. 28
sTRJarBRRY ROCT-LJ7fJlL C IIThCL Iii OREGON
By
J.
cox
Doi C. 'oto
There are two groups of root-weev.tls that co reat iriji ry to
strawberries in Oregon each year. These groups crc tI e rachrhinus
group, which are supposed to be introduced pests, and the Dyslobus
group, which are native insects tat have caged their $cod habits
from native vegetation to strawberry. The jrach1rh.nus proup contains
the ooiimion, mediui and large-sized stravibcry root-woevils and gill
evTThT The Dyslobus
hereinafter be cled the coimtoi strawberry ro
group contains at least two definite weevil cioin, serious injury t'b
strawberry in Oregon nd this group will hereinafter cc called the native
erfectively apply neasures for
strawberj root-weevils. In order
control a 1iow1dge of tho life history of these two groucs of weevils
is necessary.
Weevils Differ in Life Habits and Color
The eOn strawberry root-weevils pass the winter urinoips.11y
in the grub stage, althougn n soe uarLs of rgon (hiricr elevations
than 1Fillametto Valley) the eiult.s also lie orr the wiiter These
to hc adu't
overwintering grubs pupate (fori c'o"oow-1we ells) iid
It
is
ii
Le
adult
tge
only
that
3ontrol.
weevil stage at berry harvest
oft'
s
bait
is
ess'atial
as
icaT
irompt
a
measures are effective.
it onIts a short time for t 'dults to nature and bein layin
ggs,
vthi'.h will defeat the object of the bait.
The native strawberry root-weevils differ f row the common weevils
in tner life nistory in -cunt t
Lri tessed
n
h edult sae in
n ii curing in
the ground, Tne adults eerie out 0± ce Lround e'rl
March and feed on the leave ol -c e stravberr. These weevils lay egs
fed o tb-s roots of the strawin April and May and tne result xi. xi
berry until late summer when they pu.pate and change to adults.
The common strawberry rootwoevils not only differ frow. the other
group in their life history buL iso ii the odor ot tw adult ievils.
ieraI c.,olor, while tn native weevils
They are either brown or ela& i
usually appear to be grey but o loser exc i wtoo ne an be seen to be
øovered ith minute scales i hsoh lLrC off t llio op rr and crass
reflections.
Common Root-weevils Controlled by Dait
onmxon.strawberry root-weevils can be easily and iheaply controlled
ein and 5-,
the use of bran bait. A bait ad° of Tdriea ansi
iii tests
as
prover
effocuiv
oalxsate or sodiur.i fluoclicaue aico
strarberry
rootThe
nitiv
or
nt
Sta
oonduoted by the Oregon 2xp ri
The
weevils are not so effectively controlL.c o YãTt. T1-ie toisoned apple
bait is the only oa-lt that eaw b-s reow anded and uilss favorable weather
prevails for a few days after application, good results cannot be expected.
The bran bait may be made a cording to the following formula
Bran --------------
Water
Sugar
--
5 gals.
Calcium arsenate or sodium
fluosilicate (9d pure) Lixing and Ap1ication
procedure has mroven satisfactory in mixing the bran
The
sugar
is
dissolved
in the water and the solution thoroughly
bait:
As
soon
as the bran has absorbed all of the solution
mixed with the bran.
and is uniformly moistered tne powerd roion is acded and thoroub1ly
The following
mixed with the moistened bran.
The apple bait is a patented product and may be purhased from
dealers in spray materials and insecticides.
The bait is applied by ulacing about one tablespoonful in the
o3of each plant. 100 pounds of the bran or apple bait will
treat from one to three acres, depending on how close the plants are set.
center
Time of Application
The coimnon strawberr1 root-weevils can he controlled by an
of the pupae have changed to adult s.
application of baiec when from 75 to
ii:
oerry
barest In some places
s
made
du
This aI2at ion usual
elevations
and
in
1lisLates
colder
than the Willamette
mostly in higher
Valley) it is necessary to rnaie an eddiionel auplication for the oiorwintering
adults in Auril or May at about blossoming time.
The aplioation of the bait for the native root-weevils is made
about April 1.
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