The progressive farmer. [volume] (Winston, N.C.) 1886-1904, 1891-05-26
THE r
H POTATO SCAB.

dUO1N VI LII OCLOAOH ASA 49,
with results of considerable interest.
While heretofore the disease has been
considered to be an effect of numerous
agencies, especially chemical or phys1-
cal, and more recently has been re-
ferred to the attack of a pacific
Bacteriun, it is shown, by expert
ments at this Station, to be due to the
direct action of a very peculiar fila
mentous fungus of extremely small
dimensions which has been found
invariably to accompany the disease
wherever it has been examined by the
writer in New England.
This fungus produces an ~evanescent
gray film in connection with the dis
ease, generally visible without a lens,
especially in the earlier stages OF the
affection, and has been obtained alb
solutely pure for experiment, by the
ordinary methods of isolation used in
bacteriology. On nearly all neutral
or slightly acid substrata used for
it's cultivation, it forms a compact
lichenoid growth accompanied by a
peculiar dark stain which ditiuses
from it through the nutrient substance.
It's f~ructifcatiOn is aerial and consists
in the production of short rod-like
bodies and spirals; the latter terminal,
the former resulting from the general
augmentation and breaking up Of the
aerial flaments into short pieces; the
| general mass, which is blush grey IN
color, closely resembling various forms
Of bacteria in shape and size, the diam
eter Of both the vegetative and repro
ductive portions Of the plant reaching
only from five to eight ten-thOusandths
of a milimeter, on the average. The
fungus, which except for its apparently
true branching and aerial qualification
resembles in some respects certain Of
the polymorphic Bacteria, cannot as
yet be referred to any described form
and answers to no generic description,
as far as has been a~scertained. 1t is
readily propagated by means of its
"spores, as we'll as by the smallest
possible portions which can be detached
from its vegetative filamentS. When
transferred from pure cultures to
young growing pOtato-tubers, it repro
duces the disease upon them with Ger
tainty at the point of application, I'M
der rigid experimental conditions.
Thisfact, together with the invariable
association of the fungus with the dis
ease in nature (as far as observed by
the writer after it has once been recog-
nized ndsought for, may be considered
practicable evidence of the connection
between the two as cause and effect.
Whether the disease under cOnsidera-
ton is identical with that which, as
previously mentioned, has been refer
red to a bacterial origin isquite another
matter, and there is every easOn to
believe that the two are wholly distinct
affections except in so far as their re-
suits are somewhat similar. Further
than this nothing can be said, except
that the disease here investigated
usually takes the form of what has
been called deep" scab, which may
possibly be found to be distinct in
origin from the "surface 6cab with
which it is often associated even in
New England.
In connection with this subject a
study is being made of another organ
ism morphologically Identical with the
s~cab-fungus; but apparently somewhat
different physiologically. This organ
ism, whichmay nevertheless ultimately
identical with the scab-fungus, is one
of the cOmmonest forms of growth
upon rubbish, old hay o. straw, barn
yard and similar substances.
and it's study is being prosecuted witha
view to ascertain whether this identity.
if it car be shown to exist, may not
furnish a rational explanation of the
much miscellaneous rubbish, or fertili-
zed with barn-yard manure, is gen
orally associated with scab in the
potatoes raised upon it.
Having occupied so short a time, the
work upon this disease has been of
necessity preliminary and it has not
been possible to consider experiment.
ally, the practical side of the question
to which attention will be given in the
further Investigations to be carried on
during the coming season.-ROland
ThGrter, MycOlogi8t.
WHY EESILAGE PAYS.
DR.. O. T. Everhart addressed a
Grange meeting in York county, Pa.