Morris tribune., 1911-04-21
Clean Seed-==MethOd
Of Disinfection.
BY e. c. Stakman, Minnesota
University Farm.

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The Importance of clean seed to sue
cessful farming is more and more rec
ognized. Seed may be impure, not
only on account of the presence of
noxious weed-seeds, but also on ac-
count of the presence of plant disease
germs (sporesy. 1T is a matter OF
common knowledge that many serious
plant-pests are distributed by means
of infected Seeds The classes of dis
cases which persist. in the seed are
caused either by fungi or bacteria,
very minute parasitic plants. Fungi
may live in the seed in vegetative
form; that is, their threads may live
during the winter inside of the seed
coats; or their reproductive bodies
(spores) may adhere to the outside of
the seed. - liz. -
Naturally, then, there are two meth
DDS of getting clean seed. When the
fungous threads are inside the seed,
one of two things must be done:
Either the seed must be replaced by
some known to be free from disease,
or some special method of destroying
the fungous threads, without prevent
ing the seed from terminating, must
be devised.
AS an example of the first class, in
which the fungus lives inside the seed
during the winter, may be mentioned
the anthracnose ofa beans, which
causes the unsightly spotting of the
pods. No seed-treatment has been de-
vised which will kill the fungus with
out also killing the seed. Seed from
unaffected pods must be selected. AS
an example of the second class, the
loose smuts (blackheads) of wheat
and barley may be mentioned. To kill
the smut-threads which are inside of
the barley or wheat kernel, special
method of treatment with hot water
has been devised.
In case the fungous spores live on
easier. 1t is only necessary to kill
the spores on the outside of the ker-
mel The covered smut Of barley, oat.
smut and stinking smut (bunt) of
wheat can thus be prevented. In
treating grain to prevent these three
smuts, formalin is most often used
The standard strength of solution is
one pint of formalin to forty or forty
five gallons of water Merely dipping
the seed in the solution, or spraying it
on the seed, will prevent the occur.
renee of these smuts. The same is
true of fax wilt. In this case, how
ever, double precaution must be
taken; the seed must be treated and
sown on land which has not grown
lax for five or six years.
There are two diseases of potatoes
common in Minnesota, both of which
can be prevented, at least partially, by
using clean seed. The common pota
to scab can be prevented by seed
treatment combined with crop rota
tion, since the disease persists both
on the, tubers and in the soil. The
seed potatoes, if soaked for two hours
in formalin, used at the rate of one
pint to thirty gallons of water, can be
disinfected. If they ara
then planted on land which has not
grown potatoes, beets, turnips, or cab
bage-which are subject to the same
four or five years, scab
free crop should result. The internal
brown rot of potatoes also persists in
the soil, and may be carried to new
soils by affected tubers. In this case
the fungous threads are inside the
tissues of the potato, so seed-treat-
ment would be of little value. 1t Is
necessary, then, to select absolutely
clean seed. The presence of the dis
ease can be detected by cutting across
the stem end of the potato, brown.
lsh discoloration indicating it's pres
ence