Iron County register. [volume] (Ironton, Iron County, Mo.) 1867-1965, 1886-02-04
POTATO.ROT.
Preventives Suggested BY Two Reliable
Authorities.

4
In a report on the crops of Michigan,
Prof v NJ Spalding, of the State Uni
versity, makes some important sugges-
tons respecting preventive measures
against the potato-rot, which we are
glad to quote for the benefit of our read
| ers-
The disease. he says, is contagious,
and is due. if not solely, at least prima-
rily. to the presence of minute para-
site fungus, phytophthora i7!festass. The
destructive effects of the fungus are gen.
orally first observed upon the tubers late
| in the fall; but the disease is present
much earlier in the season, and may be
| recognized on the tops by certain char
| acteristic blotched. black or brown spot
ted. dead appearance. A critical exam
| nation would show on the diseased tops
| numerous small white spots, which,
| when highly magnifed. are found to be
miniatures forests of slender stems
| growing out of the surface OF
| the leaves and stems of the vine.
| These tiny stems produce spores
| (called summer spores) by mill
| lions, so small that million could
| easily lie side by side on square inch
| without crowding. When ripe they sep
arate from the stem and fail. and under
| the influence of water become exceed
| ingly active, and push out slender tube
| capable of becoming mature plant IN
| side the potato plant.
| The mature fungus lives in the tops OF
| tubers of the potato, and is also micro
| scopic. II consists of very numerous,
| f17b In
threads which grow through the tissues
of the potato. appropriating its juices,
| and so impoverishinT the tissues that
| they either break down directly or are
| invaded by bacteria and other low forms
which induce putrefactive decomposi-
| ton The mvcelium or internal tube
| like thread of this fungus is perennial
| and hardy, but the disease depends, pri-
| marty, for its spread the following sea-
son upon the preservation of this N.Y.
| celium in the diseased tubers and tops.
| These facts respecting the source of the
| disease suggest certain preventive meas
ures, which Prof. Spalding thus sum-
| mariZeS:
l. From what has been said it follows
that the parasite may often live over
winter in the tops of decaying tubers
| left in the fields after harvest. Pru-
| dence would, therefore. dictate the COM
| plete removal and destruction of such
| refuse. 1t should be buried or burned.
| 1t should not be used for compost
| 2 Store the harvested crop in dry cell
lars. and sort over several times, at
short intervals. carefully removing from
| the bins every tuber which shows the
least sign of decay. Remove, also, to a
| separate pile, those tubers which have
been lying in contact with the diseased
| ones. The sorting viii be facilitated
and the decay hindered by storing the
| tubers in casks, barrels or small boxes.
| Potatoes buried in quantity in fields will
| be likely to rot TIA toto during the COM
ing winter if. by chance, any infected
| tubers were buried with the sound ones.
3. Plant next season only tubers that
are entirely sound, outside and inside.
| The black spots contain the fungus.
! Some tubers may appear sound on the
surface and be diseased within. Deter
mine the soundness of the tubers by cut
ting at planting time. To plant dis
| eased potatoes will insure a continuation
| of the rot
f. Even if direction No. has been
followed, more or less of the potato
fungus will probably remain over winter
in the fields ready to grow if there is an
! opportunity. Do not. therefore plant
| in the same fields as last wear, nor in
| adjoining ones, nor near fields planted
| by neighbers. if some more remote To-
| cality can be found
| 5. Take advantage of the prevailing
direction of the wind. Our summer and
| autumn winds are chiefly from points
! between south and west There is,
| therefore, chance of escaping wind
blown spores by planting to the south
| west of other potato fields, or TO the
northeast of woodlands or other large
uncultivated tracts.
| 6. The growth Of the parasite is
favored by moisture and stopped by
drouth It is rapid in rainy weather
and when there are heavy dews, Usually
| the rot is much worse upon clay lands
or other soils which retain moisture.
/ Choose, therefore. light and dry soil
| for planting.
| Prof. Spalding adds that it has been
/ experimentally shown that, with only
moderate watering. the summer spol es
| will penetrate the soil to a depth of sew
eral inches. SO that chilling up will
| not protect against them. 1t is also
| probable, he thinks, that nothing can
| be busted upon the growing plants, or
| otherwise applied to them. with much
| benefit. But we have received a note
| from Rev Marsena Stone, of Leland
| University, New Orleans, in which he
says
Il will give you the result of an ex.
! pertinent made in 1851, in Norwich.
| \. Y, when l was pastor there, that
resulted so well. and was so environed
| as to convince me that l had discovered
| a preventive of that terrible pest. My
| garden was touched by four others. that
had patch of potatoes adjacent to my
own patch la each. They were all
| planted in the usual way. using no
| preventive. / went to a lime-kiln in
| the neighborhood. and procured the
wood-ashes with which the lime was
| burned. and which was mixed with lime,
probably nearly or quite half-and-half.
| and dropped a handful of the lime and
ashes with my potato seed, and when
| the potatoes were fairly up / dropped
| upon each hiil a small handful while
the dew was on, two or three times
while they were growing. The other
four patches had very few sound
potatoes They lost nearly ali. and I
had scarcely a rotten potato, no
| more than is usual in a healthy
| field. 1t is very easy experiment to
| try. l have not since had occasion to
| try it in Ohio, and know nothing more
| of the efficacy of the means than this
single fact But since four other gar
| dens Law against mine, and nothing but
| a fence between the patches and mine.
Il y IL \