The Mobridge news. [volume] (Mobridge, Walworth Co., S.D.) 190?-1917, 1913-07-04
Life History Of the Loose Smut of
Wheat.

N@%NfN fs0 PhAA '1o OF1A lily a
the embryo or little plant of a healthy
looking wheat grain. IL the spring
when the grain is planted he smut
plant starts 70 grow at the same time
as the grain. The little smut plant
grows up through the wheat stem and
enters the head. which is converted
into a mass of spores, with the eXcep-
ton OF the rhachis or stalk of the
head. The smut masses are naked
and these spores are scattered by the
wind at about the time the wheat is
in full bloom. Some of the spores
alight inside the chaff Of the wheat
flower and at once begin TO grow. The
tiny threads of the smut enter the
wheat Oyary or young grain and pen
citrate to the embryo or little wheat
plant. Here the smut plant grows
without forming spores. When the
grain is ripe there is a sound and
health.y looking kernel which contains
smut threads. that may develop loose
smut the next season.
BY a comparison of the life histo-
ries of sinking and loose smut of
wheat. it can be readily seen that the
loose smut is much harder to kill be-
cause Of its location in relation 10 the
seed. In the sinking smut there is
an external infection by spores that
can be readily reached; while in the
loose smut there is an internal infec-
ton by a smut plant that can be
reached only with difficulty. Another
point to notice is, that there is not
the danger OF infection by handling
the grain after harvest, from loose
smut spores as in the case OF stink
ing smut. "All of the infection by
loose smut takes place in the field be-
fore harvest. Sound seed of wheat,
when mixed with loose smut spores,
will not get this loose smut; but II
sound seed is mixed with sinking
smut, it will produce sinking smut al
most without fail. Threshing ma
chimes cannot. therefore. spread the
loose smut. while they certainly can
spread sinking smut" bulletin 122
U. Of MIMI.
From the above it can be seen that
III tie treatment u AhC OWN ~ ShA"|
plant must be killed in some manner,
and yet this treatment must not Kill
the young wheat plant in the embryo
Of the seed. This a be done by a
rigid method, known as the Jensen
modified hot water treatment. This
treatment is severe, since it is apt to
injure the terminating power OF the
| seed. 1t is also very hard to perform.
After treatment. the grain should al
ways be tested to determine just what
per cent has been killed, and then
allowance should be made for this in
planting. The best way to avoid loose
! smut is to get seed from fields that
were known not TO contain any loose
smut and that were not located near
smutted fields of the same kind of
grain.
Treatment of Loose Smut of Wheat.
Freeman and Johnson, in Bulletin
152 of the Z. s. Department of Agricul-
ture. recommend the following meth
cd for the treatment Of loose smut OF
wheat and barley.
Clean seed should be soaked for
from five to seven hours in water at
ordinary temperature, II degrees to
% degrees c. (63 degrees to - de-
grees F., 1t should be placed in
small, loose sacks or wire baskets con
tanning not more than one-half peck
each and drained for a short time. 1t
is Of the greatest Importance that the
seed be treated in small lots in order
that all OF the grain may be quickly
and uniformly brought to the desired
temperature. Two tubs or watts of wa
ter should be provided. In one tub
(No. p the exact temperature re-
CURED should be maintained. The 9TH
er tub (No. II is used for bringing the
grain to the temperature Of the treat-
ment, so as not 10 lower the tempera-
ture in tub No. 2. Galvanized iron tubs
of 20 to 40 gallons capacity and kero-
sene or gasoline double-burner stoves
are sufficient for treatment. The
drained sacks or baskets of seed
should be plunged into tub No. l for
a minute, then transferred to tub No.
2, and kept agitated while immersed
at temperatures and for the periods
specified below, the temperatures men
/ toned being maintained as nearly as
possible:
For barley. 10 minutes at SO degrees
C. 125.6 degrees F..
For wheat, 10 minutes at "a degrees
c. 129.2 degrees F..
In treating barley, if the tempera-
ture should rise above 50 degrees c..
(125.6 degrees F. the time of INNER
sion must be reduced to ten minutes
at SO degrees C. 127.4 degrees F. or
five minutes at "a degrees c. (129.2
degrees F.). Above "a degrees c..
129.2 degrees F. there is no safe mar
gin. If the temperature falls slightly
below 50 degrees C. G25.6 degrees F.)
the time of treatment should be in
creased in proportion. A temperature
lower than 81 degrees c. (123.S de-
grees F.) will not be effective. In
treating wheat, if the temperature
should rise above "a degrees C. 129.2
degrees F.) or fall below 50 degrees
c. G25.6 degrees F., the time for i'm