Port Tobacco times, and Charles County advertiser., 1846-01-29
MISCELLAN ECU S.
MILDEW.

Very few perhaps are aware of the nature
of that substance called mildew. The fol-
lowing is an abstract of lecture by Pro-
fesser LINDLEY, of England, on the subject ::
Mildew is often confounded with blight,
honey dew, &C., but il is distinct sub
stance, and peculiar to peculiar tribes of
plants. II generally appears ON the leaves
or stems, in the form of red, aCh1te and
black spots, as number of minute projec-
tions, or frosty incrustations, or brownish
powder, spreading more or less rapidly, till
the plant is destroyed. Mildew is fungi of
different kinds, and these are divided into
three classes list, those which grow or
lie on the surface ofleaves; Cd, those which
are formed in the interior of the stem or
leaf, and produce when ripe; and Sd, those
which only attack the. roots. All these
seldom appear but in autumn.
The first of these fungi I'M ure the plant
by preventing its respiration. One of the
most common of the fungi, which attack
the common cabbage, is the Cylindrospori-
am comcentricuna, and they have the ap-
pearance of small white patches or specks
of frosty incrusiation. The mildew which
attacks rose bushes, and many other flower
ing shrubs, is kind Of Uredo, so called,
from Ura, to burn or scorch for it gives
to the plant attacked the appearance of be-
ing scorched. The fungus called .acrospo-
riun, .MoniLioides, resembles when magnifi-
ed, string of beads, and consists of a
number of globules which, when ripe, fall,
take root. and form fresh strings, or neck
laces. Sometimes tufts of these appear,
fixed TO stalks, and are then called .ASper-
gillus, from their fancied resemblance to
the brushes used for sprinkling holy water.
The superficial mildew which infects the
onion, and is fatal to tha. plant, is called
Botrytis, or bunch of grapes. The bean
and pea have a superficial mildew Uredo
Fabe) which spreads along their leaves
like white roots curiously interlaced
The second class of fungi which spring
from the interior Of the leaves and stems,
are the most fatal. They appear in sort
of bag or case, supposed to be formed Of
the cuticle of the affected leaf These at
tack the oak, pine, and other forest trees;
the genius is the Rcidimm pine, found on
pine trees has. when magnifed, the appear
ance of number Of nne-pins. When ripe
it emits bright orange colored powder. A
mildew of this kind attacks barley, and is
very injurious. 1t is vulgerly called pepper
brand. The Urego Segetum, or smut, is
destructive not only to barley, but TO wheat
and oats. 1t destroys the grain, which is
converted into kind Of jelly, and attacks
the leaves and stems. The puceinia grant,
mis- which attacks corn, is formed in the in
terror of the stock, and, when ripe, burst
forth into clusters, like punches Of grapes,
Of dark-brown color. The ergot on rye
is a well-known and destructive species of
mildew. II grows out of spike of grain,
like prolonged kernel; is long, horney,
and cartilaginous. 1t originates in the CEN
tre of the stem. 1t affects maize, and vari
Gus species of grass.
The principal fungi of the third class are
two, which attack the roots of plants, and
both resemble truffles. One of these I2hi-
zoctonia Crocorum attacks crocuses. 1t is
called by the French Lamort du sqtran,
and soon destroys the whole crop. The
other fungus (Perioza tomentosa) is found
on the potato, lucerne, &c. 1t turns the
roots to purpllsh hue. They are both
propagated by spawn or fbres, which cling
round the roots. All these fung propagate
rapidly, requiring only twenty-four hours
to come to maturity. One mushroom will
propagate 250,O0O,OOO. Plants, DR.. L. saws.
are generally most affected by superficial
fungi after long drought. Red Plants are
said to be more liable to mildew than anv
otba. Mr. Rauar heS found that .,..."
grains of corn in lime-water will cure, or al
least prevent, the spread of the internal mil
dew. There appears, however, as yet, to be
no cure for mildew in the roots, but by form