Shepherdstown register. [volume] (Shepherdstown, Va. [W. Va.]) 1849-1955, 1921-10-20
Plant Diseases.


What becomes OF the plant diseases
OF orchard, garden or field during the
winter months?
Insects protect themselves in. var
ious ways during the cold weather, or
lay cCgs that hatch out in the spring.
I The f"ngi and bacteria which cause
diseases have also arranged their life
activities for long winter sleep. One
OF the important problems in studing
plant diseases or insects destructive
to plant life is to find out how they
spend the winter, and consider means
Of fighting them during this dormant
period.
In discussing this matter, Dr. N. ].
Giddings, plant pathologist Of West
Virginia University, says:
"The over-wintering habits Of the
fungi and bacteria are often very diff
cult to discover, and years Of careful
study have failed to reveal this part Of
the life history Of certain diseases.
Ii is also fact that the same disease
causing organism may live over winter
in more than one form, or on more
than one host, and that the winter habits
of the same fungus may vary consider
ably under different climatic and soil
conditio-e.
"ln Canada and the northern States
&c black stem rust of wheat spends
lie winter on the wheat stubble, but
passes to the taroerry in the spring
before it can AGAIN affect the wheat
In the South where the winters are
comparatively warm we find that this
disease lives over winter on the grow
ing grain in a form which is able to
Immediately reinfect the wheat in the
spring. The barberry is a necessary
factor in many sections of West Vir-
ginia, as far as all evidence to date is
is shown.
NEARLY every one is familiar with
the apple rust and its method OF winter
ing on the red cedar before it can in
feet the apple. In this case, as we'll as
in the case OF the wheat stem rust OF
the northern States, we may control the
disease by eliminating the least desir-
able host.
"The two wheat smuts have quite
different methods Of living over win
ter or during the dormant season. The
loose smut fungus penetrates the grain
just at blossoming time, but it does
not develop so as TO cause any visible
injury at that time and remains dorman,
until the wheat terminates and begins
its growth. The smut fungus then
grows forward as rapidly as the whea,
and by the time the wheat
is ready to blossom it takes possession
of the food which should go to form
the head, and We have merely the mass
of black smut spores which are carried
to other wheat heads and infect the
young grains.
1.-The other sinking smut or bunt, on
the other hand, is carried over BY
spores which cling to the outside Of the
wheat kernel. 1t is quite easy to de-
stroy these smut spores which are on
the outside of the grain, but it is more
difficult to get in at the loose smut liv-
ing inside the grain.
fortunately, it has been found that
the latter fungus may be killed by a
temperature two or three degrees below
that which would destroy the wheat
germ, and this method OF control is
sometimes used.
THE twig blight Of the apple, which
is also known as fire blight and blossom
blight, is quite common in small home
orchards. The bacteria which cause
this disease are very easily killed BY
drying, and they cannot live in the
dried-out portions of dead twigs but
frequently do live over just in the edge
OF the living tissue Of tw;oe a, hr,,ch