Delaware Republican. (Wilmington, Del.) 1843-1874, 1873-11-27

PRIzr from An ESSAY on rHE potato DI.

PRICE FOR AN ESSAY ON THE POTATO d.
sEAss The loyal agricultural society, Of Lon |
dot, has lately offered priz' Of fl00 sterling |
for the best al on the p1tito disease and the |
modes OF its prevention. The competins essays |
are to be sent in before the end of 1873, with |
the proyiso that oil the information they con- |
tain shall be founded on experience and origi-
nal observation, and not upon compilations
from books or other writings. A summary OF
what Is believed to be known on the subject
prepared by Mr.. Caruthers, hos been published
by the society {, aid ess,yists In their labors.-
In this we are informed that the potato disease
has been known for ages in the western coun-
tries Of south America, but that Its first ascer-
talned appearance In the United States and
Canada was In 1912. II reappeared In these
countries In the following year. Ia the latter
half Of July, 1854, 1t first appeared in Belgium,
and within two months lis presence was 70 ord
ed IN England, Ireland, Scotland, France, Ger-
many, Denmark and Russia. Since that peri
cd 1t has never been entirely absent from po-
tato crops, although less destructive In some
seasons 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, microscopic fungus That
this is the cause, and not tile 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 ovoid bodies not
more than 1-S00th OF an inch long When ore
of them rests on the under surface Of the Leaf,
with sufficient moisture present, 1t pushes out
q slender tube through Its own ruptured coat,
which penetrates the epidermis, passing rapid
ly through the leaf, branching and rebranch-
Ing ; the spotted appearance being due to the
brown coloring matter contained IN its slender
root. This root, or mycelinm, as 1t Is called
sends its branches into the air, and these are
! swollen at the exiremites, b, airing minute ova
l kNli artyhf lab aada nr ha
6 passes down the leafstock into the stem, and
thus reaches other leaves, as also the under
ground branches. and through them the poia
= toes themselves. In one experiment, spore
4 placed on the leaves Of n healthy plant, on I'M
a 4th IT February, extended over the entire plan
: by the oh.
; Such cells as are pierced by the mycellum ar
: destroyed AMI the sta-ch granules are cohsum
ed, putrefacton soon begins, first affecting tn
cell walls and then the starch. Although til
q minute spores may abound around the disease
y plants and OH the soil they never appear to Al
>. tack healthy plants through the roots, hut 10
a yariably commence their ravages by aitachin
n themselves TO the stoms or leaves The prope
"a method OF arresling the progress of this dlseas
Va | appears 10 be the destruction, by fire, Of III
-, plants affected whether leaves, stems or tuber
"A If these are left to decay in the field, or get in
90 the manure in the farm yard, the mycelium
a the spores will be retained, ready to germina
IA whenever the necessary conditions are presen
- Moisture is indispensable to the termination
IA these Spores and an excess is always dangerou
a. Thorough draining is therefore indicated III
90 der the circumstances. In conclusion the T
N, port states that there is nothing in one varie
of potato rather than another to predspose Il
A. attack by the fungus, and that whether Il
N plants be healthy or otherwise, wherever d
~, sporc rests, and finds suitable moisture 1t e
~ inmates. When it has once obtained foot
re Its quick growth, during which innumerat
NV spores are developed, causes rapid advance
y, the disease.