The Goodland republic. [volume] (Goodland, Kan.) 1891-1907, 1899-12-01
rscieptffe Ameriean.l


in the past few years that crops which
they formerly cultivated with success
could no longer be grown. They titled
and fortified their fields with the usual
care, but the plants withered and died
from no apparent cause. A careful in
vestigation Of the evil by the depart
ment Of agriculture has shown that the
/ soil in many regions OF the United
States, devoted to the cultivation Of
| special crops, is infected with several
most deadly varieties Of parasitic fungi.
! The experiments and researches Of the
| department have been exhaustively de-
! scribed by DR.. Erwin Smith in a paper
which he read before the Botanical sec
ton Of the American association for the
advancement OF Science, and which we
publish in full in the current issue Of
the Scientific American Supplement.
DR.. Smiths investigations show that
soil fungi have ravaged the fields Of the
watermelon region, the cotton section,
the cabbage district Of New York state,
and the tomato lands Of Florida. To
such an extent has the melon fungus
infected the soil Of our southern states
that watermelon growing has been
sometimes rendered impossible, and in
certain parts Of South Carolina, Vir-
ginia and Mississippi the industry has
been almost given up. In one Of the
finest cOttOn-producing districts in the
world 1.-THE "Sea Island belt, extending
from South Carolina to Georgia. many
growers have been compelled to aban-
don their devastated fields. The cab
bage growers Of New York and the to-
mato farmers Of Florida have suffered
similarly.
That the evil is primarily due to soil
parasites or fungi is fully proved by
Dr.. Smiths experiments. Merely by
burying the fungus in the earth the
characteristic signs Of contamination
are obtained in the plant. Microscopic
examinations show that the parasite
completely fills the water-ducts of the
stem. The leaves wither, and, if the
weather be dry, the plant neverrec
Even if the weather be moist, the plant
soon drOOps under the heat of the sun.
A plant may be contaminated at any
stage of its development, from the seed
ling just shooting from the ground,
with no leaves except cotyIedons, to
the ull-grOwn vine with ripening
fruit and dense foliage. From external
indications alone the disease cannot
be diagnosed. Only by a microscopic
examination Of crOss-sectiOns Of the
plant is it possible to ascertain the true
cause of the willing OF the foliage, for
the white, cOttOn-like stuf1ng which
fills the passages is an unmistakable
sign of sOiI-fungus infection As the
plant dies the fungus comes to the sur
face, and in fruiting changes its form
entirely. In his attempts to cross
inOculate the varieties Of fungi DR..
Smith has been unsuccessful. Nor
pholOgically the parasites are appar-
emily similar; phFsiOlogicaIy they seem
altogether different from one another.
The farmer naturally asks What is
the, remedy for this soil infection?
Unfortunately, no answer can be given.
The malady is Of such recent discovery,
and so little is known of the fungi, that
for the time being, only precautionary
measures can be recommended. The
usual methods Of curing vegetable dis
eases are utterly Ineffective. A field
once attacked by a particular parasite
can hencefOrth produce no healthy
plants subject to contamination by
that parasite. Perhaps, as DR.. Smith
suggests, the disease may be due to a
disregard Of one of Natures first re-
quirements - the rotation Of crops.
Year after year, the grower Of especial
crops will plant his ground with the
same vegetables, until at last the soil,
besides becoming 'sick," accumulates
a mass Of dccaying tissue which con-
stitutes an excellent culture-bed for
parasites. The moral is plain enough.
The crops grown in soil still untainted
should be carefully changed every two
or three years. Contamination can be
prevented only by burning diseased
plants and by exercising the utmost
care in separating the infected vines
from the bay and other crops stored
away during the winter; for so tensc-
iously do these fungi cling to life that,
if not destroyed, they will attack the
soil in the following spring with the
same deadly effect as in the previous
year.