The Redwood gazette. [volume] (Redwood Falls, Minn.) 1873-1940, 1881-11-10
Smut In Corn.

Smut In Corn.
At this season OF the year every
farmer takes more or less interest in
the curious growths 80 often found on
the ears of Indian corn, and to which
the name OF corn smut has very gener-
ally been given in this country. As
commonly found, it consists Of soft
rounded or pointed outgrowths, whitish
externally and black and powdery
within. These appear for the most part
upon the ears, but occasionally upon
the tassels and the leaves. Where they
occur upon the ears each outgrowth
springs from the place upon the cob
which should have been occupied BY q
kernel; in fact, as we shall see, each
outgrowth is q kind of transformed
kernel. This disease ia due to the
growth of an internal parasitic plant in
the tissues of the corn. It has been
carefully studied by many botanists,
and its vegetable nature has long been
known, as well as much of its structure
and life-history. In common with
many other parasites the smut plant
has very simple structure. Instead
of being composed Of leaves. stems,
roots, flowers, ETC., j: is no more than
an aggreg ation of simple cells arranged
more or less in rows or threads. These
threads constitute the whole plant
body, there being nothing to correspond
to the organs 81 the ordinary higher
plants. One would look in vain to find,
for example, anything to answer to the
leaves or the roots of common plants.
Furthermore the smut plant differs
strikingly from ordinary vegetation in
being entirely destitute OF a green
color. But the vegetable Psychologists
are agreed that this is simply correlated
with its parasitic habit, it being we'll
known fact that all true parasites are
pale in color, or at any rate not green.
A plant which is green, that is. which
contains the pigment chlorophyll, is
capable of getting a most important
part of its food, its carbon, from the
air, or rather from the carbonic acid in
the air, but a parasite gets its carbon
as well as the rest of its food from some
other plant by direct stealing, hence it
has no need of ohlorophyll.
The species was long ago designated
as Ustilago maydis, the smut of Indian
corn. Fischer Won Waldheim, an emil
nent botanist of Warsaw, Russia, has
detected the threads of the smut plant
in the stem of corn down almost to the
root. and extending far out into the
leaves. They are always more album
dant in the richest parts of the corn
plant, and hence in the young kernels
they abound, as may be seen bY making
thin slices of the earliest stages CT the
smut as it appears in the ears of corn.
In these richer parts of the affected
plant the ends of the parasitic threads
swell up somewhat, and from their pro-
tOplasmic contents form small round
spores. which are ut first smooth and
light-col0red, but later roughened ex-
ternally and of deep brown or black
color. These spores are set free by the
softening (deliquescing) of the now
mature smut. threads; this is the soft
and watery stage of the disease. After
this stage the water evaporates, leaving
little more than the mass OF dark spores,
which are now ready to be blown away
by the lightest breath of wind. These
spores are the reproductive bodies of
the smut plant, and while structurally
they are much simpler than seeds, they
still perform the general function Of
seeds, that is, they sooner or later give
rise to new smut.
The most careful experiments yet
made fail to show the precise method
by which the terminating spore sends
its threads into the corn; probably
there are one or more intervening
stages between the spore and the ap-
pearance of the disease in the corn, as
there are in the case of the rusts, which
are to be regarded as quite close rela-
tives of the smuts. But if we do not
yet know the complete life-history, we
know certainly that the spores in some
way reproduce smut, and that the great
er the number of spores the greater
will be the amount of the smut. 1t is a
matter of common observation that in
general the smutted ears increase year
by year in field which is planted sue
cessively with corn. On the grounds
of the Iowa Agricultural College sever
al years ago plat of three-fourths of
an acre, planted with sweet corn, was
observed to have few smutted ears;
these were permitted to remain on the
ground and disseminate their spores.
Next year the plat was again planted
with sweet corn, and the number of
smutted ears was observed to be great
ly increased. These we're again per-
mitted to remain on the ground. The
following season sweet corn was plant
ed for the third time. and the smut in
this crop was so abundant as to make
it difficult to find sound ear. The ex-
pertinent was carried no further, as it
had demonstrated the fact that the
spores when left upon the ground are
the next years crop. The remedy is a
simple one, and consists, first, in care
fully gathering and burning all smutted
ears and other affected parts of the
corn, and, second. in being careful not
to plant seed which may have spores in
contact with and adhering to the kerr
nels.-Prof. c. E. Berry, loaOa Agricult-
araI College, IN N. z. Tribune.