New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1873-10-30

PRIZE FOR Az ESSAY Oh THE POTATO DlSfAsE-
The ROYAL Agricultural Society Of London has lately
offered prize Of 600 sterling for the best essay on
the potato disease and the modes OF its prevention
The competing essay to be sent III before The end
of 1873 with the proyiso that all the information
thew contain shall be founded on experience and
original observation, and not upon compilations
from books or other writings.
4 summary Of what is believed to be known on
fine subject. prepared by Mr.. Caruthers has been
published by the Society to aid essayhts IN Their
I,bors In this we are informed that the potato dis
case has been known for ages in the western coun-
tries of South America but that its first ascerained
appearance in the United States and Canada was III
1913 1t reappeared in these countries in the follow
ing year. In the latter half of july 1S45 1t first ap-
peared in Belgium and within two months its pres
ence was recorded in England, Ireland, Scotland
France Germany, Denmark, and Russia. Since
that period it has never been entirely absent from
poato crops although less destructive IN some sea-
sons than in Others.
The report goes on to state that there is no longer
any dispute as to the real cause OF the disease
namely. a microscopic fungus That this is the
cause and not the effect is shown by the fact that
the disease has been produced in healthy plants by
transferring the spores to the leaves or tubers.
These spores or seeds are ovOd bodies not more than
18p0th of an inch long. When of them rests on
the under surface of the leaf with sufficient moist
ure present it pushes out slender tube through its
own ruptured coat which penetTates the epidermls
passing rapidly through the leaf, branching and re-
branching; the spotted appearance being due to the
brown cOlOTing matter contained IN ITS slender root
This root OF myccllum as 1t Is called, SENDS us
branches into the air; and these are sWOlen az the
eytrcnitics bearing minute oval bodies which are
the seeds or the spores. 1t passes down the leaf
stal into the stem and thus reaches other leaves
as also the underground branches, and through them
tbe potatoes themselves. In one experiment spores
placed on the leaves Of healthy plant on the 4h OF
february extended over the entire plant by the 9th
Such cells as are pierced by the mycelltm are
DESTROYED and the starch granules are consumed
pntIefactiOn soon begins first affecting the cell
walls and then the starch. Although the minute
spores may abound around the diseased plants ana
on the soil, they never appear TO attack healthy
plaDts through the roots, but invariably commence
their rayages by attaching themselves to the stems
or leaves. The proper method OF aITestlng the pro-
ess of this disease appears To be the destIuctlOn
~ fire of The plants affected whether leaves stems
ar tnbers III these are left TO decay in the field OF
get into the manure in the farm-yard, the myceun
or the spOres viii be retained ready to gellnlnate
whenever the necessary conditions are present
Moisture is indispensable 10 the geImihatloh OF
these spores AID an excess Is always dangerous
Thorough draining is therefore Indicated under inc
circumstance In conclusion the report states thai
there is nothing ia one variety oi potato IIHei 'UI,
another TO predspOse it so attack by Tie fungus ana
that, whether Tie plants be healthy or otherwise,
wherever the sICre rests and inds hhltabu ihoSlho
10 terminates When II has once ob,abeu q IopllnE
it's quick growth, during which innnmcrahle sports
are developed canses a raDd advance OF the Oi3caf