The Fort Peck press., 1935-08-01
WEEDS INVESTING
MONTANA RAPIDLY
WHITE TOP AND PEPPERGRASS
SPREADING AT ALARMING RATE;
SHOULD BE COMBATTED
MONTANA STATE COLLEGE,

(MONTANA STATE COLLEGE)
White top, also, called hOary creSS
and perennial peppergrass, is spread
ing through the state at an alarming
rate, according to A. III. Post, assoc
late agrOnOmist of the experiment
station at Montana State college. 1t
is a comparatively new perennial
weed and one that is more difficult
to control than Canada thistle. There
fore, every farmer or land owner
should take definite steps toward pre-
venting the production of seed, adj
vises the agrOnOmist. A special eff
fort should be made to locate all in
tested areas and begin a definite pro-
gram Of eradication or white top will
be as widely spread as Canada thistle.
"Let the old adage, a stitch in time
save nine be our guide" says Mr.. Post
White top spreads rapidly by under
ground rootsta1ks and by seed. The
foliage is grayish green in color and
most of the leaves are quite slender, but
may be circular on the more mature
stems. The flowers are small, a white
color and are borne in dense clusters.
The name, white top" has has been
derived from the general appearance
of the flower clusters. Due to the fact
that white top spreads by running root
stalks, it will be found in dense patches
except where the plants have been
scattered by tillage. The seeds which
are borne in heart-shaped pods are
small and reddish brown in color. This
weed would be especially serious in
clover and alfalfa seed fields because
the white top seed could not be Separat-
ed satisfactorily.
"When the weed areas are rather
large and occur in cultivated fields, the
most practical method of control is
through tillage," says the ~agronomist.
"Plow the infested area in the spring
and keep absolutely clean or black dur
ing the entire growing season. This
tivations in a single year. Some states
are adopting a tWo-year clean fallow
program which requires about 38 Gull
tivations. This will indicate the ag-
g~ressiveness of white top and the i'm
portance of e~radicating it now. Our x
perience with white top would indicate
that two years of clean or black fallow
will be necessary to eradicate it. The
implements for %cultivating weed
areas are the blaze weeders and duck
foot cultivator.
Calcium chlorate is being recon-
mended for the control of white top,
when occurring in small areas and in
areas inaccessible to tillage. The spray
is made by ~dissolving two
pounds of calcium chlorate in one gal
of water. Apply q gallons of this
solution to one square rod of area. This
will be equivalent to five pounds of the
dry chemical per square rod of area.
The chemical should be applied when
the white top is in full bloom or pre-
late in the fall. If the late fall
treatments are given the white top
should be moved when in blossom to
prevent the formation of seed. A fol-
IoWup spray treatment usually will be
necessary.
Experience indicates that it will be
necessary to practice clean or black
,alloW the year following the chemical
This means a tWo-year pro-
gram and considerable expense. How
ever, the expense now will be small as
compared to what it will be five years
rom now if white top is allowed to
spread without interruption"
Mr.. Post says he found the worst in
'estation in the area of Billings and
vest. Plant samples a be sent for
Identification to the agronomy depart
nent of the experiment station at Mon !
ana State cO1lepe ROZeman.