Los Angeles herald., 1909-10-04
DANGEROUS PEST


favorable to plant life in general that
ranchers have good reason to fear the
consequences of the introduction of
the thistle. The weed is a menace to
the agricultural prosperity of any dis
trict, and to exclude it successfully
and permanently from California
would be we'll worth all the trouble it's
eradication would cost.
The botanical name sf the Canada
thistle is "Carduus arvensis." and it
has probably a worse reputation than
any other species of plant. So black
is its character, so utterly destitute
Of any redeeming feature, that it is
no wonder recent reports to the eff
| feet that the pest has been introduced
into this section are causing much
alarm among ranchers, and many are
asking that official action be taken to
eradicate the invader at once. That
their fears are not unfounded is ad-
mitted by all who are familiar with
the harm done by this aggressive
weed in eastern states. If it should
thrive in the climate of Southern Cal
ifornia and spread as it has in other
sections of the country it would
cause an enormous annual loss to the
ranchers.
The Canada thistle was a trouble
some weed in the fields of southern
Europe as early as the beginning of
the sixteenth century, and about
hundred years later was observed
growing about the residences Of
French missionaries in Canada In
this way it received the name by
which it is now known in this coun-
try. 1t was introduced into New
York and Vermont with the hay and
equipage of Burgoyne's army in 1777,
and the farmers of Vermont became
so alarmed by its progress that a law
was passed by the legislature in 1895
directing its destruction on all lands
within the state. Since then success
sive generations have attacked the
thistle spasmodically, soon becoming
satisfied of their ability to keep it in
check and relaxing their efforts. But
the thistle has never relaxed. 1t has
continued to grow and spread until it
is now found from Maine to Virginia
and westward to North Dakota and
Kansas, and on the Pacific coast from
Washington to Northern California.
/ The Canada thistle is usually intro
duced into new localities by the seed
contained in shipments of hay. In
one county in Oregon it was first no
ia
chine recently brought from the east. !
1t would have cost only a few cents
to have cleaned the machine, but the
thistle has done damage to the extent
Of thousands of dollars since its in
PRODUCTION. When the seed germi-
mates a rosette of leaves. lying almost
fat on the ground, is formed. These
leaves are prickly on the margin,
smooth and green above and some
what woolly below. The following
year the plant sends up a branching
flower stalk to a height of from one
to three feet, bearing rose-purple
flower heads about three-fourths of
an inch in diameter. Usually very
few fertile seeds are formed until the
plant has been established for several
years; therefore its determination is
not difficult if immediate action is
taken. OEce established in a locality,
the thistle at once begins TO spread
by means of running root stalks,
which creep along under the surface
Of the soil and throw up shoots at
frequent intervals, often forming
dense patches.
Many methods of destroying this
weed have been proposed, but the
only one that is at all times effective
is the application of chemicals which,
being absorbed into the tissues of the
plant, will kill the roots. While the
plow and hoe will eradicate the plant
on thin soil, they are useless where the
roots can penetrate to a considerable
depth. The department Of agriculture
recommends the following chemicals
as being the most effective: Sulphuric
acid, nitric acid, muriatic acid, car
bolic acid and sodium arsenite. Strong
lye applied to growing plants will
kill them, and few drops of the 9TH
ct cneInlCdiS may De dppllbu 70 yOuLS
shoots and growing branches or
poured into the hollow stems when
the plants are cut in flower. Merely
to pull the plants, as is done with
other weeds, is useless, as the small
root stalks remain in the soil and
three or four shoots are thrown up
to replace the one removed.
The legislatures OF twenty-four
states have passed laws prescribing
the Canada thistle as a noxious weed,
among them California, which in 1872
made it unlawful for any person in
the counties of Humboldt, Siskiyou,
klamath, Del Norte and Alameda to
permit it to ripen seed upon their
land. 1t is to be hoped immediate
steps will be taken to eradicate this,
the worst Of all weeds, before it be-
comes scattered over a wide territory
and so firmly established as to ripen
fertile seed.