Gunnison news-champion., 1920-01-23
THE ALFALFA wEEvIL
Most Important lnseot Enemy TO
Colorado's Chief Crop.
- c. d. Wakeland }

The alfalfa NesNM ms come 70
Colorado 10 stay. Regardless Of pre-
cautions taken 20 check It's spread or
control il, il Is but 4 question of time
until Il reaches alfalfa-raising sections
tha. are now free from the pest he
problem that confronts farmers of 4
srnall portion OF the state this year
may, az no distant time, be the con-
cern Of men who are now unsuspeet-
ing Of danger.
IL is the purpose Of this short article
and others to follow 70 present facts
known about the weevil 10 the people,
not only in the infested areas. but al
50 in the counties whene no weeyil Is
known 10 occur al present, but which
at any time may have Il TO combat.
To give n better understanding of
the alfalfa weeyil IN this state and
the part II will play in agriculture, il
will be hrst necessary to describe
something Of its early history and
spread
The alfalfa weevil occurs all over
Europe, a portion of northern Africa
and eastern Asia. II probably occurs
throughout all the regions where al
fal!a is cultivated in the Eastern
Hemisphere, but rarely causes dam
age sufficient to be reported Bulletin
ll0, Utah Agricultural Experiment
station }. II was frs; discovered in
the United States by farmers in the
vicinity of Salt Lake City. How it
reached this country will never be de-
fnitely known. and one mans surmise
Is about as good as another's II
could have been transported in i'm
migrant goods. in nursery stock or in
numerous other ways. Ii is probable
that il existed in Utah for several
years before its presence became
known, for il was discovered only aft
er il had done considerable damage.
TO the alfalfa in that locality.
With the fields near Salt Lake City
rs center, the weevil has spread out
ward at an average of ten miles a
year since 1904 or 1905. Until re-
Gently il was known in no state but
Utah, but now il is known in Oregon,
Wyoming, Idaho and Colorado as we'll
( The spread of the pest has been stea-
dy and general and for the most part
have occurred by flight or crawling
of the adult insect. In recent years
an isolated infestation has been dis
covered in Idaho and another in
Colorado. These were probably were
established by the adult being hauled
or shipped in hay, in packing of nurs-
cry stock or in household goods from
the older infested regions.
In July 1917 the weevil was dis
covered 10 De present and to be doing
considerable injury to alfalfa in n
small locality in eastern Delta and
western Gunnison counties. Sub
sequent work in the late summer and
fall of the year proved that weevil
was present in the alfalfa fields cover
ing an area of several square miles.
From the extent Of the injury il was
apparent that the pest had been es-
tablished in the Paonia locality for
several years and residents report
having seen it and its injury on pre-
vious years but did not suspect that
it was alfalfa weevil.
AS it was an entirely new insect in
this state assistance was asked of the
Bureau of Etomology of the U. S.
Department of Agriculture. A repre-
sentative was sent from Salt Lake
City where the Bureau had been do
ing investigational work on the life,
history and control of the weevil. The
state etomologist met him in Paonia
and several days We're spent in the
field making examinations to deter
mine the extent of the infestation and
studying local conditions. At first it
was thought there might be a possi-
bility of exterminating the pest when
it was learned that such large area
was infested and that there was such
an abundance and diversity of food
plants, it was decided that it would
be impracticable to attempt local
eradication.
At the time the weevil was first dis
covered as existing in Colorado, the
General assembly was meeting in
extra session. Realizing the import
ance of immediate action against so
dangerous a pest the legislature was
quick in its action to pass bill pro-
viding funds to enable the state ento-
mologist to handle the situation.
Immediately upon funds becoming
available work was begun in the state
to combat the alfalfa weevil. The
plan of work has been along three
general lines-scout work, to deter
mine the rate and extent of the
spread; investigation work to study
the life, history and habits, and expert
ment Of control work
During the first year of study of
the weevil, its spread was a pleasant
surprise. Instead of advancing ten
miles as it has been known to do in
other localities. its greatest known
spread in Delta county for the same
period was about three miles. This
spread was only where the alfalfa
fields were continuous.
1t was hoped that natural barriers
such as mountain ranges and large
stretches of barren land would prove
an eifectual check to the weevil to
new territory, but this was not true.
During the year of 1919, it was
found on large ranches which were
separated from infested territory by
large areas OF adobe bad lands"
Judging from work of the previous
year, it might have been expected to
have spread distance of two or
I-kl i.x