St. Landry democrat., 1889-05-11
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Potato Rot.

We know that potato rot is due to the
attacks of fungus, says Orchard and
Garden.
We know that this fungus is true
parasite, and that all kinds and varieties of
potatoes may be attacked by it.
We know that high degree of humid
ity is necessary for the development of the
fungus, and that its attacks are most viru-
lent during wet, sultry weather.
We know that heavy undrained land
and clayey soils favor the disease.
We know the appearance of the dis
ease on the tops, and how quickly these
may become affected and destroyed.
We know how seriously the tubers may
become affected, and how the loss from
rot NAV amount sometimes to more than
one. half of the crop.
All do not know that these tubes are
generally infected by spores from the tops
washed into the soil by rains.
We know that the fungus in germlnat
ing usually produces zoospores, that these
zoospores are exceedingly minute particles
of naked protoplasm, and that they are
extremely sensitive to circumstances I'M
favorable to their further development.
We know that these zoospores rest for
short time upon the surfaces of the plants
they are destined to enter by further de-
velopment.
We know that it is by the penetration
of these zoospores into the potato plants
that the latter becomes infected with
blight and rot.
We know that very minute quantities of
sulphate of copper will destroy these
zoospores
We know that the fungus enters the
tubers, and that if these are placed where
it is warm and damp that they will quickly
rot.
We know that by keeping the tubers
dry and in cool place they are not likely
to rot, although the fungus may already
have attained some growth in them.
We know that the fungus lives through
the winter in the tuber and that the plant
ing of such potatoes serves to carry infec-
ton to a new crop.
We know that the fungus in the tubers
may generally be detected by discolora-
ton or browning of the flesh underlying
the skin.
| We know, from what has just been
said, that such potatoes should never be
used for seed.
1t is said that the seed may be disin-
fected, that is, the fungus in the tubers
used destroyed, by soaking the whole po-
tatoes for twenty four hours in solution
of sulphate of copper-four ounces In
water enough to cover one bushel
1t is said that the tubers may be disin,
fected by keeping them for few hours at
temperature of from 105 to ITO degrees.
This degree of heat is said to kill the fun
gus without destroying the value of the
tubers for seed.
1t appears from the above that
We ought to disinfect the seed potatoes
by heat or by soaking in blue vitrol solu-
ton, if there is any question as to their
containing the parasite, remembering that
this cannot always be told by the eye.
We ought to select for planting light
sandy loan, or certainly soil well drained.
We ought to spray the tops with some
solution of sulphate of copper that will
adhere well in order to effect the destruc
ton of the zoospores that may come upon
them. After these spores have penetrated
the plants and the disease disappears d,
the applications will haze comparatively
little effect.
We ought to store our potatoes where
no dampness will collect about them, and
where the temperature is low, say thirty
five to afortyf five degrees.-7he Western
| Rural and american St0Ckman.