The Grit-advocate., 1905-04-21
The Beet Web-Worm.

Bulletin 9S of the Agricultural Ex-
pertinent Station of the Colorado Agri-
cultural College at Fort Collins is de.
voted to description of the worms
that prey on the sugar beet, the web
worm, the army worm and the cut
worm. Following are extracts from
the article on the cut-worm by Prof
Clarence =. Gillette, entomologist:
The beet web-worm did more or less
damage in all the beet-growing sec
tions of the state last summer and fall.
In the vicinity of the Loyeland and
the Longmont factories very little
harm was done, but the beets grown
for the sugar factories at Rocky Ford,
Sugar City, Fort Collins, Windsor,
Greeley and Eaton all su%ered to a
considerable extent in some Of the
fields.
This insect does not possess any
great notoriety as yet as a crop pest
Twelve years ago last summer it at
tracted some attention because Of its
injuries to sugar beets in Nebraska
during the months of July and August,
and because of its injuries to a field of
mint in Michigan late in September.
Since 1892 it has not attracted much
attention.
THE first complaint that came to
the experiment station last summer
was August 18th. On that date went
with Mr.. C. M. Liggett to his ranch,
about ten miles northeast of Fort Col
Inns, and found the worms doing con-
siderable damage.
Mr.. Timothy. agriculturist for the
Greeley sugar factory, told me that he
first noticed the worms at Sterling
August Sd, and at Greeley August 10th.
The worst of the injuries were over at
Greeley August Goth.
Growers have estimated their losses
all the way from one to five tons per
acre as the result of the injuries by
the worms. Analyses by the chemists
at the sugar factory indicate loss of
about two per cent. in both sugar con-
tent and In purity in beets that We're
defoliated badly during August. Prob
ably more than 1000 acres of beets
suffered substantial loss from the web
worm in Colorado last year.
..Remedies.-If the worms are num-
erous enough to attract any attention
at all late in the summer or in the fall,
the beet ground should be plowed
deeply and as soon as possible after
the beets are gather, for the purpose
moths will not be able to escape the
following spring. If it is impossible to
plow in the fall, then the surface of the
ground should be thoroughly narrowed
or disced for the purpose of crushing
the worms and bringing the tubes to
the surface where freezing and thaw-
ing and the attacks of birds may de-
strOy large proportion of the worms.
"The worms accomplished their work
of destruction so quickly that it is i'm
portant that the beet grower should be
prepared to check the injuries as soon
as they are seen. In order to do this it
will be necessary to be on the lookout
for the moths, which will always ap-
pear in the beet fields from one 70 two
weeks before the worms will be no.
ticed. These moths span about one
inch from tip to tip of their wings
when spread, and are of dark gray
ish or grayish-brown color.
'They will fly up and go Il short dis
tance and then suddenly alight us
ually upon leaf of plant. The pres
ence of the moths in anything like
large numbers among the beets should
be the signal to prepare for war by
procuring quantity of poison and
spray pump or some other instrument
for the distribution of the poison upon
the beet leaves.
Some combination of arsenic, as
arsenite of lime, arsenate of lead, paris
green, or london green should be
used. The arsenite of lime is the cheap.
est of these but is little more trouble
some to prepare and apply. Arsenate
of lead is more easily mixed and ap-
piled, but is by far the most expensive
poison to use. Paris green settles
badly in the barrel or tank and must
be kept thoroughly stirred. 1t would
be cheaper than the arsenate of lead,
but dearer than the arsenite of lime.
The chief objection to paris green last
year in Colorado was its serious adul-
teration with white arsenic, causing it
to burn foliage"
The worms will probably appear in
large numbers about the middle OF
May. Other broods appear about June
10th, the first week in July and about
the middle of August.
Be prepared with poison and spray
pump so as to strike the blow in time
to prevent serious injury to your beets
if the worms should appear.