The Highland and
Agricultural Society of Scotland, with the view of ascertaining the state
of the potato crop last year, again issued a series of Queries similar to
those circulated among the agriculturists of Scotland in 1845. The results
of the investigation are now given in the form of Reports from various
parts of the country, including districts which had escaped the disease in
1845. The Queries sent will be found in the previous Report, and it is
needless to repeat them here. It does not appear necessary to enter into
an analysis of the Reports, as the results in most instances correspond
with those of 1845.
ABERDEENSHIRE.
No. 1. - Mr John Hutchison,
Monyruy, near Peterhead, 19th Dec. 1846.
I have this season to give
quite a different report from last year; as, instead of never having seen
the disease in this quarter, I cannot now hear of a single instance within
many miles, where the potatoes have escaped.
On the 3d of August, I
first noticed the leaves of a few potatoes affected; nothing could then be
seen on the tubers. I put two men to cut off the leaves of about one-third
of the crop. On my return from Aberdeen that week, I found the tops of all
the others gone, and a few of the potatoes affected. The disease spread
very fast after that for at least a fortnight; when it seemed to stop. The
tubers did not grow after the tops were smitten; and most of the diseased
ones were close to the stem, or near the surface. There might be
one-fourth to one-fifth of the tubers left usable ; these not mealy, but
waxy. The purple cluster was most affected. No potatoes that I have heard
of being raised and pitted, have kept a week - all have gone. Most people
here have left their potatoes in the ground undug all winter, by which
means it is expected they will have a few in spring. I have dug mine daily
(until the late snow), without much difference on them for months. I have
also planted from one and a half to two acres, which I have examined
several times, and they appear to be keeping well; they were carefully
picked.
The half-bad potatoes I
made into fine potato starch. I had some of all my different sorts
planted, without any dung, purposely for seed next year, on poor dry land
dug out of grass; and these were all smitten the same as the others ; most
of them not being earthed up, and being nearer the surface, were worse. I
had, however, a number of recent seedlings among them, one of which in
particular was nearly safe in the tubers, the stems having decayed, and it
seems to have been more hardy than the others. My early garden potatoes
were ripe, and dug before the disease appeared—quite sound and of fine
quality; they were put on the surface of the ground to green, but decayed
faster than any other; not one was saved.
It would appear to me the
disease came from the atmosphere: the weather at the time was dry, very
warm, frequent fogs, especially during the night, with a great deal of
electricity in the air.
No. 2. - Mr Wm. Garden,
Balfluig, January 1, 1847.
Tub potato disease was
first observed in the Alford district about the 1st of August 1846. I am
not aware of any instance of the disease in this part of the country in
the crop of the previous year. The leaves of the potato were first
affected with small brown spots, which afterwards extended to the stems,
and last of all, the tubers nearest to the surface of the ground became
diseased. As the disease progressed, the leaves and stems gradually sank
down and withered. Some of the plants were in flower when the taint
appeared, but most of the varieties had passed the flowering stage, and
had plums more or less formed. When affected with the disease, the flowers
became withered, and the stalks of the plums faded and sank down with the
rest of the plant. The tubers, when affected, presented a rough appearance
on their surface; and their substance under the cuticle had a brown
gangrenous appearance, to a greater or less depth, according to the extent
of the disease. In the black and purple varieties, it was difficult to
distinguish the diseased from the sound, without removing the cuticle. The
disease evidently extended from the leaves and stem downwards. The mean
temperature of July was 59.12 deg.; and the mean daily range, 11.9 deg. of
Fahr. The depth of rain which fell during that month was 5'7 inches. The
weather about the time of the appearance of the disease was hazy and
sultry. The mean temperature of May, June, July, and August, was 57.48
deg. The amount of rain during that period, 15'15 inches. In this district
I had never observed such a mean high temperature accompanied with such an
excess of moisture, during these months. No variety of potato cultivated
here, has entirely escaped the disease; although sometimes one variety,
sometimes another, has been more or less affected on different farms. With
regard to one kind of potato, these observations do not apply, as, on six
or eight different situations, in which it has been grown, it has been
much less affected with the disease than any other variety. I do not know
the name of this variety, but it is a small round potato, of a light pink
colour, with deep eyes. [Probably the variety named cups.—Edit.] In all
cases, though slightly tainted, it has produced three-fourths of sound
tubers, and in many instances much more. From the loaves and stems having
been affected, the tubers did not attain that size which they otherwise
would have done. I had some of this variety grown on land which had been
long under cultivation. Of these, fully three-fourths wore sound. I had
also about an acre of the same kind on land which had been trenched last
year, and which never had carried a crop. It was manured with farm-yard
dung and ashes. The crop, though affected in the leaves and stems, was
nearly all safe in the tubers.
It would thus appear that
potatoes grown on new land are less subject to disease. I have seen
several varieties of potato recently raised from seed, all of which were
affected with taint. The average produce of sound tubers last year in this
district, did not exceed from three to four bolls per acre. In very many
cases the produce was much less. The disease seems to have affected the
potato plant in a particular stage of its growth, and the different
varieties were affected accordingly, the late kinds escaping with
comparatively less injury. The disease seemed to stop its progress about
the middle of September, as it did not extend to more of the tubers after
that period. But this may have arisen from the circulation of the juices
of the plant having been arrested. The disease does not seem capable of
being propagated but in the living plant. I cannot hazard a conjecture as
to its cause, but it certainly seems to be produced by atmospheric
influence—a predisposition having been in the potato, probably contracted
by excessive cultivation, and forcing manures. That atmospheric influence
must have been one of the causes, I have not a doubt, as I am aware of an
instance of a diseased stem on a hill at the distance of a mile from any
other cultivated spot.
The potato from which the
stem grew, had probably been carried off by a crow. I stored up my sound
potatoes about the beginning of November, and they are still in a sound
state. They were placed in a long pit, in the usual way, without any
ventilation. 1 have also seen sound and diseased potatoes pitted together,
with apparently no bad consequences. A common plan in this part of the
country has been to take up every alternate drill, and cover up the others
with the plough. This plan seems to answer very well. No chemical
application can restore diseased potatoes to a sound state. I know of no
remedy for the disease; but I would strongly recommend an importation of
potatoes from the country in which they are indigenous.
I may observe, that the
mean temperature of last year was 47.73 deg. Fahr., and the quantity of
rain 40.65 inches. This temperature is fully 3 deg. above the average mean
of this district, and the amount of rain ten inches more than the average
quantity.
No. 3.—Mr Peter Paton,
Fraserburgh, 5th January 1847.
The taint on the potatoes
first appeared about the 1st July 1846, after a fortnight of excessively
hot foggy weather, such as made respiration difficult to human beings. The
part connecting the leaves lost its strength; then the leaves grew black,
and the stalks presented the same appearance that bean-stalks assume when
ripe; the tubers, as the leaves fell from the stalks, became discoloured
in the skin, and this proceeded more and more, daily, until they bad the
appearance of a rotten apple, but still hard. If there happened to be any
safe potatoes, they were invariably the lowest. The flowers fell off the
same as the leaves; few of them attained perfection. None of the varieties
have entirely escaped the disease; but the long blue has suffered least in
this quarter. Those lately raised from seeds have been equally affected
with those long grown from the tubers. In new ground of a poor
description, with a mixture of black sand and mossy soil, they have been
less affected; in rich soils, especially black, they have been the worst.
Many of the potatoes have been left in the ground, and such as have been
taken up, have been pitted in long narrow pits, and mixed up with earth,
approaching as nearly as possible to the state in which they grow, the
tainted being carefully separated from the safe, they being easily
distinguishable from the colour of the skin. Many of the tainted were
converted into farina at the end of the harvest; but such as were allowed
to remain under ground, have entirely disappeared.
No. 4.—General Byres of
Tonley, 15th January 1847.
The disease was first
observed about the 31st July, a few days earlier than it made its
appearance on other potatoes in the neighbourhood; which may be accounted
for by their having been earlier planted, and farther advanced than on
other farms around.
The long white kind was
affected about a week before the other varieties; but the others suffered
equally when about the same stage of growth. One kind, that had been
raised from plums, at Tonley, and grown for eight successive years, were
also affected, but were about a week later in being so than any of the
other varieties, and suffered fully as much as any.
One part of the crop was
upon good old land, a part of which was planted with long whites, manured
with bone-dust, and not a single potato was saved. Another part was
manured with guano, of which about a fourth part was taken up safe.
Another part manured with farm-yard dung, yielded much the same quantity
of safe potatoes as the guano, but were rather larger in size. Another
part of the crop was upon newly improved land, which had not previously
grown potatoes, though one or two crops of tares had been taken from it.
The tops of these were affected about the same time as those on the old
land; and although the potatoes made no progress in size afterwards, there
were not nearly so many actually bad potatoes as upon the old land, and
probably rather more than half an average crop was secured, and stored
partly in pits, with alternate layers of earth, and partly left in the
drills and covered up. From a late inspection both seem to be keeping
perfectly well.
On another part of the
estate, a small patch of ground, newly improved, on a hill side, at a
considerable elevation, the potatoes were affected with disease in the
leaves and stems, later in the season, but about the same stage in growth
; and although the disease extended to the tubers, a larger proportion was
perfectly safe, than has been found in either old or new land at a lower
elevation. They are of excellent quality, and continue to keep good,
having been stored in round pits covered with turf and earth in the usual
manner.
No. 5.—Mr Hugh M'Connach,
Secretary to the Vale of Alford Agricultural Association, Alford, 27th
January 1847.
In the year 1845, the
potato disease was unknown in this part of the country ; the case,
unfortunately, is now far otherwise. This mysterious and destructive
disease was first observed in this quarter about the 2d of August, last
year, in a small plot of early potatoes, in a garden on an elevated
situation, where mildew or any thing of that nature would have been least
expected. In this case the disease had made some progress before it was
observed. On the 8th August, symptoms of disease showed themselves in a
small field, distant about 3˝ furlongs from the first mentioned place,
which had been planted pretty early in the season with common potatoes,
and, up to that date, had a most vigorous appearance. As this field was
every day carefully examined, the disease was noticed in what was believed
to be its first stage. It commenced by attacking a single leaf near the
top of the stem, here and there, in one drill, and these leaves had a
withered, shrivelled appearance, as if their hangers had been broken or
destroyed by a strong breeze of wind. About two days afterwards, the
disease developed itself more visibly in a single spot of the field,
nearly two yards square, where the whole leaves and stems became quite
black and faded in the course of a few nights, and it rapidly thereafter
extended itself over the whole field, and indeed over the whole vale of
Alford. The rot in the potatoes seemed to commence simultaneously with the
decay of the leaves and stems. The flowers in this instance were off, and
the apples formed before the disease appeared. The tubers had not,
however, attained their usual size. They often appeared sound till the
skin was broken, and then they had the appearance of a chipped apple, and
the appearance soon spread over the whole potato, which became a rotten
mass. The weather during the whole season had been extremely sultry with a
great deal of thunder and lightning, which brought occasional heavy
showers ; but the temperature, though high, was equable, and the season on
the whole was not what might be called rainy; nor was there anything
remarkable in the state of the weather at the time the disease made its
appearance, except the excessive heat. On the 6th of August, however,
there was a pretty dense fog over the country.
It may be worthy of remark,
that in the second instance above mentioned, the leaves first attacked
were observed to be all on one side of the drill, namely, the south
side—the side next to the garden where the disease first appeared. Are we
to infer from that circumstance that the disease had been communicated by
the atmosphere from the one place to the other—the one infecting the other
at a particular stage of the crop?
Various attempts were made
to check the progress of the disease on its first appearance. Some spread
quicklime over the stems—others pulled them up— and some cut them off; but
all without any good effect. One individual diverted a strong current of
water from its course, and thoroughly flooded his field, but the more
sudden decay of his crop was the result he reaped.
The only variety of
potatoes cultivated in the vale of Alford, that has been less affected
than the others, is a round light red or pink potato, not known here by
any particular name. [Probably the variety named cups.—Edit. ] Some
varieties are more or less injured than others, and some are nearly
extirpated altogether. On a small plot of ground with a running stream on
one side of it, and a wood on the other, some long blue and long white
potatoes were planted, and not one in a hundred of their tubers was
affected; but these were raised from the ground as soon as the disease
appeared on the leaves. The ground had been brought into cultivation four
years ago, and had then carried one crop of potatoes. On the other hand,
the same sort was all but a complete failure in another field, which had
been for many years under cultivation, and the only difference of their
treatment was, that those saved were planted about a fortnight earlier
than those which were lost, and were immediately raised from the ground on
the disease making its first appearance. Some long black and long white
kidneys, and some round red, speckled-with white, potatoes, were planted
on woodland that had been trenched two years ago, and had carried two
crops of oats. Of the long black, between a quarter and a half of the crop
was safe. Of the long white there was fully one half safe, and scarcely
one of the round red was injured. But the crop was inferior in point of
size and quality.
The potatoes planted in
this Vale have been long raised from sets or tubers, and there was within
it, last year, perhaps no instance of potatoes being planted that were
recently obtained from seed; nor is it ascertained as a fact that "any
particular condition of the soil, as wetness, previous cultivation, or the
kinds of manures used, appear to have had any influence in promoting,
retarding, or preventing the disease," unless the above instances in new
land may be regarded as exceptions. For the disease may be said to have
been universal in this quarter; and no real cause can be assigned for its
vagaries. The latest varieties, however, and the latest planted, were on
the whole the latest in being affected.
The modes employed in this
locality in storing last year's crop of potatoes, have not been numerous.
In many instances the crop has not yet been raised—partly on account of
its almost total failure, and partly from a belief that those potatoes
which may have escaped would keep better in their native beds than
otherwise. The few that have been raised have been in general stored in
the usual way. In one case some were laid out in the sun till they were
thoroughly greened—being carefully picked during the greening. They were
then placed on a loft. They have been occasionally turned, and, being
sufficiently covered with straw to protect them from the frost, they are
keeping quite well. In another instance where the potatoes were similarly
treated, and afterwards gathered into a heap, and slightly covered with
earth, they soon became useless, probably owing to their not having been
earlier raised from the ground, or not sufficiently greened. Those, after
being picked, laid on wooden floors, and some mixed with soot in the pit,
appear at present to be in a healthy enough state. The disease seems to
have abated about the beginning of November.
AYRSHIRE.
No. 6.—Mr Brown of Lanfine,
5th January 1847.
In the Journal of
Agriculture published in last October, a short account is given of the
potato disease as it occurred in autumn 1845, in the parishes of Galston
and Loudon in Ayrshire. During this last season, viz. 1846, this singular
calamity has been much more severe and universal: in fact, in this
district it nas very nearly amounted to a complete failure.
On minute inquiry regarding
the growth of potatoes from the plum, I learn that this plan has been
attempted in this neighbourhood in four instances.
1. James Gilchrist, one of
my workmen, separated, dried, and sowed the seeds of the potato in the
spring, seven years ago. At the end of the third season he had several
varieties, one or more of them of good quality. These were carefully
attended to, and produced healthy plants; but in 1845, when the disease to
an alarming degree appeared in this county, these potatoes from the seed
were as bad as any other. This was so completely the case, that although
the experiment had been attended with trouble and interest, Gilchrist made
no further attempt to preserve the potatoes from seed separate from the
others. They were all mixed together in the unfortunate crop of 1846.
2. Andrew Dykes, another of
my workmen, planted seeds in spring 1845. By the following autumn he had
small potatoes of the size of pease. Of course these were of various
kinds, but, without being questioned on the subject, he says that he found
a number of these minute seedlings with traces of the disease on them. The
small tubers which were sound, were again planted during last spring. In
August the potatoes were as large as plums. The stem, however, became
diseased in the same manner as those grown from the set. The roots were
allowed to remain in the ground, as was done with other potatoes, with the
view of preserving them, but when examined a week ago, they were found
entirely decayed. The row of plants extended to about 30 feet, but there
were no remains of sound potatoes ; there were only a few decayed
fragments.
3. Thomas Aird, a weaver,
in the parish of Darvel, near my residence, in last March, following the
directions given in an essay on the potato by Arthur, sowed the seeds of
the plant in a hotbed in his garden. In May the stems had grown to the
height of three or four inches. He transplanted these in his garden in the
open air. They grew well, and promised to be a fair crop. In August the
tubers were as large as plums, but, under the influence of the blight
which prevailed at this time, the steins decayed. When examined, in
October, it was found that there were only a few scattered roots free from
disease—all the rest were quite decayed. The plums on which this
experiment was made, were obtained from the partially diseased potatoes of
the former season of 1845.
4. John Young, one of my
tenants, seven or eight years since, sowed seeds in the spring, and in
three years, in the usual way, he had full-sized potatoes. This season, as
well as the last, these have been entirely free of disease. A few of them
were brought to me some days ago, which looked quite sound. It is a firm
red potato, rather of an angular form, with the eyes more sunk than usual.
[Properties characteristic of the cups.—Edit.] It is a late kind, and I
believe of an average quality as to dryness and abundance of produce. The
crop this year extended perhaps to the eighth part of an acre; which was
surrounded by potatoes blighted in the usual way.
I have not been able to
hear of any more instances near this, than these four, in which the potato
has been propagated from the plum. It is quite evident, however, that
although this mode of propagation may have been successfully practised in
former seasons, this last year, in this district, it has entirely failed.
In fact, all the stems were blackened and decayed in the month of August,
long before the plums were ripe; and of course these could not have
produced fertile seed, or been employed to form new varieties. No doubt
seeds may be brought from districts, or from distant countries, where the
plums have been allowed to ripen, and where the disease has not appeared;
but even under such favourable circumstances, we are informed, I believe
correctly, that much time and careful selection are required before we can
produce a valuable variety of potato. We are told that the varieties from
seed are very numerous; and although, with the assistance of a hotbed, we
are able to produce full-sized tubers in one year, yet, as at first, not
having two potatoes of the same quality, it becomes a matter of time and
difficulty to determine which varieties are valuable and which worthless.
It is evident, then, that many years must be required before valuable
varieties can be extended over the country. It may happen, too, as was the
case with us, that good varieties from seed will not be able to resist the
deplorable taint which has prevailed, and which may again assail us.
The growth of now varieties
from the seed, in former times, has been highly important, and has created
all those valuable kinds which were lately in cultivation ; but from the
uncertainty of success, and the long time required to prove them, it is
not calculated to afford a speedy remedy for the present calamity. This
severe frost (December 1846) may perhaps have more effect than anything
else in checking the disease, for undoubtedly since 1837 the winters have
been unusually mild.
This disease has been
uncommonly severe in this district of Ayrshire. In fact, it has amounted
nearly to a total failure, and has already produced severe privation to a
very numerous population in our villages. My own estate is exceedingly
varied in soil, exposure, and in elevation above the sea, and in former
times was rather celebrated for the crops of potatoes it produced. Some
land at an elevation of 600 or 700 feet, rescued only last year from the
moor, and growing potatoes for the first time, produced as many diseased
as in any other situation. In a few instances, a scattering of sound
potatoes have been obtained. One farmer on high ground, had about two
bolls of sound roots, where in former years 70 bolls was the usual crop.
In a few other instances, a very small proportion of the crop was sound,
but these exceptions are of little consequence.
The crop intended for my
own family occupied about five English acres. In this field, a number of
trials were made of different varieties of potatoes, all from the set.
Different manures too were tried. From one variety of an early kind,
occupying about half a rood of land, we had about 1-12th of the usual crop
sound; but, with this trifling exception, all the rest of the field was a
total failure. When we ploughed the ground, we found only a few fragments
of diseased potatoes.
There has been a marked
difference in the appearance of the plant of 1845 from that of 1846. In
the former, the leaves and stalks were only partially blackened in spots;
the greater part of the plant being nearly in its usual state of verdure.
It however decayed sooner than in common seasons. But in this last year,
early in the month of August, without any frost, the plant became entirely
black and rotten. The decay took place in some varieties a few days sooner
than in others, but by the middle of August there was not any exception to
the decay. Even the stalks of those early potatoes of which part of the
roots were untainted, became diseased with the rest; but in these, of
course, the growth had been completed before the severe blight came on,
and in this way a proportion was sound.
About an acre of ground was
planted with potatoes from Strontian in Argyleshire, apparently quite
sound; the crop from these here was as bad as any other. The stalks and
leaves of all the varieties of the potatoes looked quite healthy and
vigorous in June and July. Early in August they began to become black and
withered, and in a few days were quite dead. With us, this sudden change
took place very soon after a heavy fall of rain, in which two inches of
rain fell in a few hours on the 8th of August (1 inch and 9-10ths of an
inch, as measured by a rain guage.) In a few days after this, the stalks
were decayed; but whether there was any connexion between this fall of
rain and the blight in the potato, cannot be settled. The coincidence in
point of time was remarkable.
The above is nearly a copy
of the observations which were sent to the Royal Dublin Society some weeks
since. At that time it was not known that the Highland and Agricultural
Society intended to collect more information than they had done ; and as
it is believed that at the present time these facts are of importance
chiefly in lessening our confidence in the propagation of the potato from
the seed, it may be proper that these should also be in its possession—
more particularly, as it is unknown whether or not they may be made use of
by the Royal Society of Dublin.
The facts connected with
this subject wore collected with some trouble. Since they were written,
those examples of propagation by the seed have been carefully scrutinised,
and I learn that they are quite accurate. Other reports of the same nature
were in circulation, but on inquiry it is understood that the four
experiments related are the only ones which have been made in our
immediate neighbourhood.
A few detached
circumstances connected with the potato disease may perhaps be worth
noticing.
From the impression that
the immediate contact of the manure with the set favoured this disease, in
fully an acre of land the manure was carefully ploughed into and mixed
with the ground; but there was not any difference in the state of the
disease. It was said, too, that guano was injurious, but in our field this
manure was not employed. We used farm manure, dunghill ashes, and also
scrapings of roads.
In 1845, in one small mossy
field the disease was more than usually marked, and to such an extent,
that a great number of fragments of potatoes were scattered about and
remained in the ground. This same field last spring was sowed with
parsnips. These grew as usual, but the ground was almost covered with
potatoes which had sprung from the remains of the former year. There was,
in fact, a full crop of potatoes of vigorous growth. Those decayed in
August along with the crop in the larger field; and when their roots were
raised, they were as bad, though not worse, than those which had grown
from sets apparently sound. It may be mentioned, that the crop of plants
from these remaining fragments was so abundant, that they were allowed to
grow rather than the parsnips. The disease in the tuber was nearly similar
to that described in the former year, though much more extensive. There
were hollow ulcers surrounded by induration of the substance.
It. has been mentioned,
that of all our crops, we only saved a small proportion of early potatoes
which had grown in the field. We had also early potatoes of the same kind
(named American early), in two plots in a walled garden. In July these
were of excellent quality for the table. Their stalks became decayed along
with the rest. When dug in the month of October, it was found that in one
of these plots in the garden the tubers were entirely rotten, but in the
other were a few entire potatoes. This is mentioned to show how apparently
capricious this disease is.
Regarding the preservation
of the potato through the winter, the belief still continues that if they
are raised, they are best kept by having them carefully separated by earth
or charcoal. Unfortunately, however, we had no roots for preservation,
except a few early ones.
No. 7.—Captain Montgomerie,
R.N., Brigend of Skelmerlie, 18th Feb. 1847.
I planted in the end of
January and beginning of February, half a field lying-near the sea, and
not much above its level, with Taylor's 40-fold, the seed of my own saving
from crop 1845, and the rest of it about the end of March, with three
kinds obtained from the Orkneys. The same seed was also planted in a field
about 200 feet above the level of the sea, the soil of both being light,
though the low one was much superior in quality. I also planted on the low
ground some seed from the Azores, and sowed some from the plum of 1845. I
never saw more luxuriant crops than all these promised previous to
flowering. The 40-fold fully realised my expectations, but with the
exception of those left for seed, were sold before the disease made its
appearance. This took place suddenly about the 8th of August, and in the
first place among the Orkneys in the low field; and I may state as a
general remark—and I paid considerable attention to the subject—just as
the flower was coming into full bloom, all not being attacked at the same
time, though the three kinds coming mixed were planted without separation,
the upper field did not suffer in the least for fully a month later.
Very soon after the disease
made its appearance in the 40-fold left for seed, I had the shaws drawn
out, and though the drill was pressed down with the foot at the time, the
tubers had by this means been brought near the surface; and after the
first unexpected hard frost when lifted, though few escaped being totally
spoilt by it, there was near an average crop. I cut the shaws of some at
the same time, but the drawing them out appeared to be a much more
efficacious method of preventing the disease extending, or rather
descending, to the tuber; indeed I am inclined to think it was an
effectual one, from the following corroborative circumstance: while
digging alongside a wall late in the spring, where some 40-fold had been
planted in 1845, and very imperfectly lifted (with the exception of about
a perch), long before the disease made its appearance, not one of those
left in the ground, above half a boll, was diseased, whereas the perch
left till after its appearance were very much so. I remarked that while
the leaves only were affected, the tubers were sound, and occasionally
even when the stem was slightly so; but as soon as the disease had
descended about half way down, we were sure to find them more or less
affected; at the same time the seed was in all cases quite sound. For
reasons not necessary to explain, nearly the whole of the low field
alluded to was two successive years in potatoes; and though I did not
collect the diseased ones off, even where most abundant, I saw no
difference in the crop, nor do I think soil, situation, or manure, made
any; if there was any, perhaps the deepest part was the best. In examining
the potato crop left in the ground about the beginning of December, I
found no diseased ones in the low field. In taking up some lately in the
high one, I found several in which the disease had commenced, and appeared
to have been suddenly arrested. I may add, that I planted some perfectly
sound 40-fold seed in soil which had not been in crop of any kind for at
least 40 years, and they suffered as well as the rest.
CAITHNESS-SHIRE.
No. 12. - Mr Henderson,
younger, of Stemster, Thurso, 2d January 1847.
Up to the beginning of
August, the potatoes appeared everywhere more luxuriant and healthy than
usual; but about that date, the disease, which was formerly unknown here,
was observed on the eastern side of the county, whence it extended to the
west coast; many parts of the interior not having been affected for at
least a fortnight later. The leaves presented the scorched and blackened
appearance usually caused by severe frost, but with this difference, that
spots often not much over a yard in diameter were affected, and in some
cases the leaves and stems quite withered, before the disease extended to
the other portions of the field, which it did most gradually. On removing
the skin, brownish coloured spots were found on the tubers, which soon
extended, and they became entirely rotten. This, however, was not the case
with all the tubers of each plant, some of them remaining sound ; though,
from the stems being injured at such an early period of the season, they
were soft and small in size, unless where the potatoes had been planted
very early.
No variety appeared to
escape the disease, though some were less affected than others. Of these
may be mentioned the black kidney, and some of the coarser kinds commonly
grown for cattle, horses, and pigs. A bed of seedlings, not in the
immediate vicinity of any other potatoes, were the first observed affected
in this district of the county. Any particular condition of the soil or
kind of manure was not observed to influence the disease.
The mode of preserving the
potatoes, which has been most generally adopted, is leaving them in the
fields with some additional earth heaped over them, to protect them from
the action of the weather, which, as they are not grown in large
quantities, and as the ground was not required for the winter-sowing of
any crop, was perfectly convenient, and at the same time prevented the
rotting or rotten potatoes from infecting the sound. In some eases where a
small quantity had been pitted in the usual manner with a light covering
of earth, they were soon afterwards found a putrid mass; which, however,
may have been caused in part by their unripe state, as the disease made
little or no progress after the stems were destroyed.
It is deserving of remark,
that about the middle of October fresh leaves were in some cases observed
to appear on the stems which were not entirely withered; and in one part
of the bed of seedlings already mentioned, a bunch of fresh stems came up,
and grew to about the height of eight inches, whilst potatoes of a small
size were formed at the roots. These facts, with others which have been
noticed, would tend to strengthen the opinion that the disease is not
inherent in the plant, but has been caused by external agency, probably
atmospheric.
DUMBARTONSHIRE. No. 13.—Mr
Wallace of Auchinvole, 2d January 1847.
Having embraced in my
former remarks every thing that I considered might be of ser\ice in
showing how matters stood in this quarter, regarding the failure of the
potato crop, I have nothing new to communicate, with the exception of what
occurred to a small quantity raised upon my own ground.
A small part of the ground
was first set with reds; they were exceedingly sickly, did no good, and
were not lifted. The remainder of the ground was planted with cups; and I
may here mention that the seed used was picked potatoes from a field that
was affected the previous year; they were the reverse of the reds, as they
sent forth a short but very healthy stem, and were generally noticed by
people when passing as being an exception to other fields in the
neighbourhood. Having observed that the blight had attacked the stems of
almost every field in this quarter, I determined to try the effect of
cutting the stems, conceiving there was little chance of the crop being
made an exception. This was accordingly done, and I have to state as the
result of the experiment:
1st. That there was
scarcely a bad potato amongst them when they came to be lifted. After they
were lifted, they were immediately put into a potato house, without lime
or any other substance being applied to them, and not a vestige of disease
has appeared amongst them.
2. Neither large potatoes
nor a heavy crop were expected, as they were slightly manured, even
supposing they had been allowed to come to maturity in the usual way. But,
as might have been expected, after being deprived of the nourishment
afforded by the stem, they turned out small, but there was little
difference in regard to the quantity.
3. The potatoes did not
show a dry mealy appearance on the table, but rather what is generally
termed "waxy." They are well tasted and perfectly sound, and I have no
doubt that they ripened in the ground after being cut. The manure used was
stable and cow dung.
In conclusion I may remark,
that I attribute my success beyond my neighbours, principally to taking
away the stem when it was in a most healthy state, and not a blighted leaf
to be seen. Others tried the same plan, but they did not give the
experiment a fair trial, as they only cut the stem away after the potatoes
had shown symptoms of disease. I have reserved the small potatoes for
seed, and, if wished, will be glad to afford the Society the result of
next year's crop.
MID-LOTHIAN
No. 32.—Mr Main, Overseer,
Whitehill, 1st March 1847.
The field on which the
greater bulk of Mr Ramsay's potatoes were grown, consists of a strong
clay, incumbent on a most obdurate and retentive subsoil. The field was
thoroughly drained at 16 feet apart, and two feet deep. When being
prepared for the seed, the soil wrought very toughly, the result no doubt
of the absence of frost during the winters of 1845-46, and the dry season
at the time of planting. I have a few potatoes planted on a light soil,
with a sandy and gravelly subsoil.
The disease appeared at the
latter end of the first week in August, in the field first named, and very
soon after a severe thunder storm. In the second mentioned field, the
appearance of the disease was fully three weeks later, and had no apparent
connexion with any special state of the atmosphere. In both fields the
first indication of the disease was a blackness of the stem at its
junction with the soil; presently the stem or shaw lost its freshness of
colour; the leaves drooped, blackened, and fell, and apparently the work
of destruction was com-plete. The blossoms, however, were a curious
exception ; the otherwise prostrated plant supported its blossoms, and
produced its fruit, and I have now a quantity of the apples from these
diseased plants, preparing for being sown as new seed this year. In many
instances after the leaves and blooms had totally disappeared (the latter
in their natural course), the apple was the only fresh green thing to be
seen about the plant; nor could I say that these were precipitated to
maturity. I had them plucked from the plant about the usual time. I may
also add, that the apples, and the seed they contained, seemed as fully
matured, and as free from any characteristic features, as any I had seen
from the crop of any previous year. They exhibited no traces of the
disease.
With me the plant and the
tubers were attacked simultaneously. I ascertained this fact from
examination immediately on the appearance of the disease; and I was thus
satisfied not only of the simultaneous, but of the independent action of
the disease on the potato itself. The effect of the disease on the tubers
was exactly similar to that of last year. The part affected presented
outwardly a dull appearance, and, when cut, had all the characteristics of
a bruised apple. This was in the first stage of the disease; afterwards
the whole became a putrescent mass. I submitted some diseased and healthy
potatoes to examination with the microscope, and I shall shortly state the
result. In an apparently sound potato, though no discolouration was
visible, there appeared, suspending itself over portions of the surface,
what I would call a light cloudy transparent humour, through which the
cellular tissue was distinctly visible. In other potatoes in various
stages of the disease, this cloudy appearance was continued, and precisely
in the degree of density and darkness of colour attained by the humour,
could be marked the progress of the disease. This humour was not suspended
over the whole surface, but hung in masses; and, except in the portions of
the surface on which it appeared, the cellular tissue, though discoloured,
as the humour became so, was visible and entire. The portions of the
tissue on which the humour appeared, became, as it were, gradually
incorporated with the latter, till the whole presented a mass of corrupt
and foetid matter. In fact, so far as I could discover, this humour
appears to be the agent of destruction. As it advances to putrescence
itself, it carries its victim along with it, till all is involved in one
common ruin. What is the nature of this humour, or how produced, I am not
competent to say ; I can only state the fact as I observed it. I may add,
however, that it is apparently inorganic, or at least my instrument was
not sufficiently powerful to detect any organism in its structure.
I am not aware that any of
the cultivated varieties of the potato have escaped the disease, nor, with
the exception of the Irish cup variety, that any have been, on the ground
of variety, less affected than others. The Irish cup is apparently our
hardiest variety. On many fields in which buffs and blues and dons were
all equally destroyed, the cup stood bravely out; and though at last it
met the fate of its neighbours, it still yielded a comparatively fair
return. The disease affected the yam in much the same degree as the Irish
cup.
I am aware of two instances
in which potatoes recently obtained from seed were planted, but they
exhibited no advantage over those "long raised from sets or tubers." All
were alike affected. In both instances, the farmers who grew them asserted
that they resisted the disease longer than the others, but with no other
advantage. This told little in their favour.
I have already stated that
the potatoes grown on my heavy land were earlier attacked with the disease
than those grown on my light soil. But this was not the only advantage of
the latter; for, while from three acres of heavy soil I did not lift more
than one boll and a half of potatoes, good and bad, from the light soil
not extending to more than one imperial acre, I lifted five sound bolls.
The latter is certainly no great result, but it tends to prove that in
light soils the taint had less power over the tubers than in heavy ones;
and my own experience has been confirmed by that of all my neighbours. In
every instance I am aware of, the light soils had the advantage of the
heavy ones. All were attacked, but the light at a later period, and in a
less degree, than the heavy.
No "previous cultivation,"
nor any kind of manure, had the slightest apparent effect on the disease.
I grew my potatoes with a great variety of manures—specific and farm-yard,
both kinds alone and in mixture—but the crops from each were all alike
affected. I had some planted with sulphuric acid absorbed in sawdust, and
applied with a proportion of some manure, and I was in hopes that would
have some effect; but though I watched closely, I could observe none. The
fact is, no circumstance connected with the potato, so far as I am aware,
had any influence in retarding the disease, with the exceptions I have
already stated, namely, the cup variety of the potato, and light soils,
and I may add whole sets. I had about an eighth of an acre planted with
whole sets; and these, long after the crop from the cut sets was blackened
and prostrated, flourished green, but certaintly not healthy. But in
whatever way and to whatever extent the disease was retarded, or rather
its effects ameliorated, no influence of any description, that I am aware
of, operated to prevent it.
Very little can be said
about the modes employed in keeping or storing the potatoes. The crop in
this neighbourhood was so very small, that the greater part was at once
consumed; and those retained for seed—probably not more than two or three
bolls on each farm, in some eases not so many—were in general pitted in
the old way, from necessity, in very small pits. In my own case I gave my
small pits as much air as possible, by means of straw ventilators and
frequent turnings. Till this date the potatoes are keeping well, though at
every turning a few are thrown out diseased. Out of from three to four
bolls pitted, I will probably be able to plant two and a half bolls, and
these are all I intend to plant this year. I should have stated before,
what I now add, that, previous to pitting my potatoes, I had them laid
thinly spread in a cellar, and turned frequently; and it was not till they
were considered sufficiently dry from this process, that they were put
into the pit.
I have already stated that
the disease had an independent action on the potato, and did not appear to
depend on generation. I may now state some facts in support of this. On my
first examination of the potato immediately after the disease appeared, I
found that the potato, as well as the plant, was affected, and that in the
majority of instances the disease did not appear at the "root," but at the
"rose" end of the tubers. This was not the invariable, but it appeared the
predominating rule. Now, had the disease been conveyed to the potato from
the plant, the natural inference is, that the end of the potato attached
to the ligatures connecting it with the plant, would have been the first
to exhibit the appearance of the taint. That such was not the case,
demonstrates to my mind that the potato did not depend on the plant for
the communication of the disease. True, the disease did in some instances
exhibit itself at the root end, but the instances of its appearance at the
"rose" end, and on the sides, were more numerous, and of necessity
compelled to the conclusion, that the appearance of any part of the potato
was not the result of propagation from the plant, but a direct and
immediate attack on the tuber itself. Another fact opposed to the theory
of propagation is, that the root of the plant was in every instance, which
I examined, the first to be attacked. Immediately on perceiving the black
appearance above ground, I examined the root, and I found it completely
diseased. The colour was of a dirty yellow, and the outer rind hard and
brittle; approaching the extreme end, the root had the appearance of
rotten wood, and rubbed to atoms betwixt the fingers. From this fact I
demonstrated to a neighbour farmer the inutility of cutting over the shaws.
He had performed this operation at once when the disease first appeared
above ground, and he was not a little surprised when he found that the
root was even worse than the shaw had been. In my own case, as an
experiment, I pulled eight drills of potato shaws from the crop grown on
the light soil, but it did not advantage me anything; the crop from the
pulled portion was equally bad as that from the rest of the field, when
the shaws were allowed to remain till the lifting time.
And as from the above facts
I am of opinion that the disease is not one propagated from the plant
above ground, so neither does it seem to depend at all on the condition of
the seed. I shall state two facts in support of this. I have already
stated that I planted about the eighth of an acre with whole sets. On the
appearance of the disease among these, I pulled a shaw for the purpose of
examining its roots and the crop of young potatoes. In pulling the shaw,
the parent potato came up with it; and what was my astonishment to find it
perfectly sound, while the root of the plant, and four out of six young
potatoes, were diseased! The parent potato was soft and pulpy, but though
I cut it into minute slices, I could not observe a single trace of the
disease. The other fact is of an opposite character. I planted in my
garden five diseased sets, two of them very bad; only one of these grew,
but it was one of the two worst. When the plant appeared above ground, it
showed a dark healthy colour, and progressed favourably: in fact it had a
much more healthy appearance, and certainly a more luxuriant growth, than
plants immediately beside it, the produce of sound sets. This plant fell
with the rest before the destroyer, but as it had grown more vigorously,
so it resisted for a longer time than the others, the attacks of the
disease. These facts prove that the sets had nothing to do with the
disease ; in fact, it did not appear in either case, till young tubers
were formed, and the plant itself was deriving independent nourishment.
These facts in my own
opinion disprove all the theories founded on atmospheric influence, and
point, if any pointing can be true, to the soil as the seat of the
disease. Immediately after ascertaining these facts, I decided that the
absence of frost in the winter of 1846, and the small amount we had of it
in that of 1845, was the cause of the disease. I argued, that, without
frost, the land lying wet and souring, would generate noxious gases,
which, independent of their individual action, would form hurtful
combinations ; these, absorbed by the potato, would speedily destroy its
vitality, and of course result in its destruction. Of course in this case
a natural inference is, that light or dry lands would not be so much
affected as heavy or wet ones; and such an inference is quite in
accordance with my experience. Again, the plant would not be affected till
left by its parent to sustain itself; such I have proved was the case. And
again a third conclusion from these premises is, that the peculiar
construction of the tuber left it independent of the plant in receiving
the disease, and such I have proved was the fact. But, specious as this
theory appeared to me, I confess I am somewhat shaken in it since the
appearance of the disease this year. The papers record several instances
of its re-appearance, I will now state an instance in my own experience. I
had saved some healthy tubers of what I considered a peculiar variety, and
had them placed in a small pit. On opening the pit a few days since,
almost every potato had a young growth of tubers attached to the eyes;
some of these young tubers were about half an inch in diameter, and those
attained to this size were diseased. The curious fact was, the parents
were perfectly healthy, but soft. These potatoes had been enveloped in
straw, and had no connexion with the soil, nor as little had they any with
the atmosphere. What produced the disease? I cannot answer the question,
and certainly it staggered my faith in my own theory, while it more
completely demolished all others with which I was acquainted. In the mean
time, it were well to resolve the whole mystery into the workings of an
inscrutable Providence, and find in the faith and hope of His mercy, a
better prospect for the potato than we can find in the fanciful theories
and vain speculations of the human mind.
Still, while the disease is
held to be a dispensation of Providence, it is nothing impious to suppose
that this dispensation is in connexion with natural causes, and that some
physical law of nature may yet unravel the mystery. I would then continue
to investigate. Let earlier, the very earliest opportunities, be taken to
observe the young plant, and note carefully the results. It would also be
useful to plant potatoes on various soils, and even to prepare soils for
the purpose; that is to give them the qualities supposed to affect the
plant favourable or the reverse ; and thus by close, early, and careful
observation, some light, however dim, may be cast upon a subject at once
so interesting and important.
I may just add, that the
second growth was a very curious phenomenon. It appeared with me about the
first week of September. The first indication was a few leaves at the
extreme top of the shaw; and on examining the root, I found some young
tubers at no depth in the soil, but they were diseased. New roots were
struck out from the otherwise withered stem, but the influence of
resuscitating life was but of short duration. Indeed, the new life seemed
confined to a very small portion of the "pith" in the heart of the stem,
which, continuing to possess a degree of activity, had, from the long time
it continued in the ground . after the first dormancy of the plant, put
forth a feeble power. This, while it is certainly a curious fact, affords
a strong proof of the tenacity of life in a plant. Strong hopes were
expressed that this second growth would produce at least a sufficiency of
seed, but these hopes were founded on hasty conclusions. Long before,
theorists had discovered the fact of the second growth, and built their
fine-spun speculations upon it. Practical men were aware of its existence,
and had been taught its usefulness to themselves or the country.
I do not think the disease
is contagious; the facts I have stated in reference to the potato plant
grown from a diseased tuber, are proof of this; for, though it became
subject to the taint, it only shared the fate of other plants grown from
sound sets, and there were no indications about it which, in the absence
of the disease, would have induced the belief that it was likely so to
fall. I also tested the contagious report of the disease by connecting the
surfaces of diseased and healthy tubers, and allowing them to remain
together for some time, but with no effect; the sound remained sound as
before.
Postscript, 29th August
1847.
I beg to add a few facts
relative to the potato disease, as it has appeared in our field this year.
I can give no precise date
for its appearance; and in attempting to fix a date, is, I conceive, one
of the errors we fell into last year in respect of this disease. My
experience leads me to conclude that it is progressive in its effects, and
in its first stages at least, its progress is slow. True, I have heard of,
what we all heard of and believed last year, the disease making its
appearance in a single night, and effecting its mission in nearly as short
a time. But unless it be the most erratic monster that ever walked the
earth, leaping over regulating principles, and effecting its object in a
thousand and one diversified modes, then I must respectfully submit, that
these achievements of single nights are to be received with a proper
degree of caution, I had almost said of suspicion. Since the potato plants
were a few inches high, I have watched their progress with much and
growing interest, and I think I am correct when I say, that since the
early part of the month of June, I have observed the symptoms and traced
the progress of the disease till now, when the largest proportion of my
crop is lying-prostrate under its influence ; and most decidedly my firm
conviction is, that it does not do its work in one night, or in two or
three nights, or days either.
I shall give a hurried
sketch of my observations. Some time in Jane—I cannot give the precise
date, but it was while the plants were yet young—I observed a brownish
appearance on the root; in some instances this brown colour appeared on
two or three parts of the same root, but invariably at the extreme end
where it joins the parent set. Towards the latter end of June, the leaves
showed indications of soilness, and inclined to curl, or folding towards
the centre. To prevent mistake, I may state that this tendency of the
plant had no characteristic in common with the disease called "curl:" I
had hardly a "curled" plant in my field. At this time, too, the roots
retained their brownness, but now rather deeper in the tinge. On the 5th
of July I made a careful examination of the field, and the unfavourable
symptoms still continued. At this examination I observed a blackness round
the edge of the leaf, and the tips of the leaves were very generally
black. We had not had any winds up to this date sufficient to account for
this appearance ; and it certainly excited my fears; the more, that I
thought I could distinctly trace the destruction of some of the under
leaves to the progress of this blackness on the edge. On the 9th of July I
have noted another examination. I give extracts from my notes:—"Many
plants have their under leaves and branches quite black, and at this stage
they invariably drop from the stem." "One of the plants I have pulled has
only a few green leaves at the top; the lower ones, with their branches,
have decayed and fallen off, and the stem presents a dull unhealthy
appearance." "The unhealthy appearance on the root is more decided, and at
the part attached to the parent appears quite decayed. When cut, the
centre presents a blackish appearance." On the 11th of July my potatoes
got a final hoeing and were set up, and to a general observer no crop
could have a more decidedly healthy and promising appearance. Many persons
laughed at my fears; but they would disturb me, for all that. On the 30th
July I made another examination. My note states:—"I have now no doubt
about the appearance of [he disease. . . . My present conviction is, that
the characteristics of the disease are a general decay of the plant,
commencing at the root. . I find various appearances of unsoundness. . . .
A universal rule is the affection of the root. In some cases of total
decay"—I had found thorough decay at this date—"the root is supple, and
its whole substance is deeply discoloured. In other cases little
discolouration is observable beyond the extreme point; but this never
fails. When the root is cut, it presents a hard woody texture, and cuts as
toughly as a young ash sapling. . . . Another invariable characteristic is
the dullness of the stem above ground, and that although the leaves appear
fresh and green." In this note, which is a long one, I mention several
indications on the leaves, arguing the progress of the plant to decay. The
first is a yellowish coloured spot—next a black daubed appearance, exactly
resembling the traditionary mark of St Peter's thumb on the haddock—and
the third a black spot. Of this spot I remark:—"Where it is very bad, the
whole plant at once manifests its unsound state, and presents indubitable
marks of decay." Again in this note I remark:—"The diseased plants are
scattered over the whole field. ... A singular characteristic is, the
centre and under leaves and branches, especially the centre, invariably
exhibit the first symptoms of decay—they are frequently all decayed when
the top leaves present no appearance of blackness; on the contrary, though
not healthy, they are yet green." The folded and soft character of the
leaves is also noted. Without further attending to notes, I may now state
that my worst fears have been realised. The progress of the disease was
slow, but sure, and now the large proportion of the field is lying under
its influence. I fear the whole will go.
I have given extracts from
my notes to prove, so far as anything so hurriedly given can prove, that
the disease is not immediate in its attacks. Its final consummation is
sudden, and it may be in certain circumstances as sudden as is contended
for; but its whole history is analogous to several of those insidious
diseases so destructive to human life—gradual at first; but, arrived at a
certain stage, the thread of life is snapped in an instant, and the being
hitherto in apparent vigour, is at once a lifeless corpse. Such is the
progress and end of the potato disease.
I will not attempt an
argument as to the cause of the disease, nor will I seek to adduce and
collate the evidence of its origin; suffice it, that I am more than ever
confirmed in my opinion that it is not the result of atmospherical
influence. In my opinion it originates in the root of the plant. What I
have already stated may be taken as a partial argument in support of this
view: I will embrace some other opportunity to illustrate and enforce it.
I may state generally that
this year, as last, at least so far as I have been able to trace, no
condition of weather, character of soil, kind of manure, or species of
potato seed, has had any influence in preventing the disease. What
influence any of these circumstances may have in retarding or promoting
it, must be de-cided at the conclusion of the season. I have had no
autumn-planted potatoes myself, and at this moment I am not aware of the
experience of others who had adopted that season for planting. I may
state, however, that I planted a few potatoes in my garden in January this
year. In April these had not appeared above ground, and on examining them
I found fully the one half rotten, but the sound sets had made
considerable growth. I lifted and re-planted two rows of these, and in the
first week of May they appeared strong and healthy; they have since
continued to grow vigorously, and have not exhibited any particular marks
of the disease, except in some cases the hardness at the root; but then
they are nearly ripe, and the shaws are naturally failing, and the potato
plant when ripe has, at all events, a greater hardness at the root than
when in the vigour of its growth. I would not like to conclude much from
this fact, especially as a portion of the season remains, and my
experience before its conclusion may be reversed. However, I am encouraged
to try again, but this season I will plant both in autumn, and again early
in the coming year. This year I will plant my seed below the dung as a
defence against frost, as, to the neglect of this in January, I attribute
the rotting of so many of my sets. I would also advise the planting of
whole sets. At all events, as an experiment, whole may be tried with cut
sets.
I have this year some young
plants from last year's seed, grown on a light soil. At this date they are
vigorous, and present no trace of the disease.
Except in connexion with
the "scab," I have not found any trace of the disease in the tuber. Below
the "scab," the same marks appear as indicated the disease last year, but
have not penetrated to any depth. I have my hopes and fears.
Such is a rapid sketch of
my experience of the disease this year; I shall be happy at another time
to fill up the outline I have now given.
PERTHSHIRE
No. 35.—Mr Archibald Gorrie,
Annat Cottage, Errol, 17th Dec. 1846.
In 1845, we, in this
quarter, heard of high temperature in southern latitudes, followed by
excessive rains, and inundations, with simultaneous complaints of decayed
and decaying potatoes. That sort of weather reached as far north as the
central districts of Scotland, by the middle of September, when drought
and heat were followed by complete saturation, and the disease appeared.
I was then deeply impressed
with the idea, that heat, followed by excessive moisture, originated and
extended the disease. I am confirmed in this opinion by the fact, that
about thirty of those correspondents who returned answers to the queries,
in reply to the first, mention that the disease appeared after heavy
rains; though they do not consider this fact as producing the disease
generally. Sir John Richardson, Bart., of Pitfour, Perthshire, indeed
says:- "The excessive moisture appeared to me to have aggravated, if it
did not cause the disease." This being my impression, I paid particular
attention to the meteorological phenomena this season, as connected with
the commencement and progress of the disease. It will be recollected that
little rain fell in the last weeks of May, this season—potato stems,
especially on strong lands, came up small and wiry ; which habit of growth
was encouraged by the warm and dry weather during the first eighteen days
of June, in which period the rain that fell did not amount to one tenth
part of an inch, while the temperature frequently rose above 80 degrees
Fahrenheit. The average temperature for the first week in June was 70
degrees ; for the second week, 63 degrees; and for the third week, 66
degrees, that is, taking the average of heat and cold for each day; this
temperature, with clear sunshine, produced excessive heat in the soil, and
evaporation on its surface, and succulent plants, such as beans, potatoes,
&c, began to languish. On the 19th, a full inch of rain fell, and by the
19th July, in the short period of thirty days, the fall of rain, with a
continued high temperature, amounted to nearly eleven inches—a fall, I
believe, unprecedented in the annals of meteorology in this quarter. This
highly saturated the warm state of the soil—completely destroying the
vegetative functions of the potato, and on strong lands, of beans.
Of the potato, some of the
tubers, from their position, were less steeped in warm water than others,
and such escaped the disease; but on frequently pulling up the shaw, I
always found diseased tubers, some of them not above the size of a grain
of barley, completely soaked and rotten, while the rootlets by which they
were attached to the stem, were quite fresh. The. blotch on the leaf,
which was soon covered with mildew, I considered as merely a symptom of a
plant decaying at the root.
I have asked some eminent
horticulturists, if by imitating the meteorology of June and July, as far
as heat and moisture were concerned, by artificial means, they would not
at any time produce a disease on succulent tuberous rooted plants, similar
to the potato taint, and have been always answered in the affirmative.
Beans generally thrive with an ordinary degree of moisture, but this
season the drought in May and the early part of June, so compressed the
soil about the neck of the plant as to render that part under the surface
much smaller than where it swelled freely, immediately above ground,
whilst the continued rains gave the feeble rootlets more moisture than
they could absorb, and by the end of July, the outer cuticle was
completely scalded, and came off with the slightest touch. The success of
beans this season was just in proportion to the porous nature of the soil
on which they grew.
I am aware that former
seasons will be referred to, and the year 1826 will no doubt occur to
objectors. Let us look to the meteorological registers kept at this place
for that year. In the month of June that year there was not a drop of
rain, and the mean temperature for the month was 63 degrees; the average
or mean for the corresponding month this year, is just one degree higher
or 04. In June 1826 there was no rain; in June 1846, five and a half
inches of rain fell on the eleven last days of that month.
In July 1826, the mean
temperature was 63° 9'; in July 1846, it was 60° 5'; in July 1826, the
rain that fell measured 1 inch and 9-10ths; in July 1846, 5 inches
7-10ths; in August 1826, the mean temperature was 61° 4'; in August 1846,
it was 61° 8'; in August 1826, the rain measured 1 inch and 95 decimal
parts; in 1846, 4 inches 7-10ths. "When it is known that the average fall
of rain in the months of June, July, and August, does not much exceed six
inches for the three months, and the annual fall averages about
twenty-seven inches, it may be expected, that from the excessive rains
during that period when the potato was growing this and last season, it is
not to be wondered at, that the potato and bean plants have been what
gardeners call damped. Having taken up so much space with the first query,
my answers to the rest shall be brief.
White Americans, London
dons, and Yorkshire reds, raised on peaty soil, on a high hill, are mostly
safe. Perthshire reds nearly all diseased. The reds, too, I am informed,
are most liable to the disease throughout Germany.
I sowed seeds of the
Peruvian kidney, and treated them with great care, but all the young
seedling plants gave way in the end of July.
I am confirmed in the
belief that the disease can be communicated to sound tubers when the
temperature rises high in a pit, by the ordinary process of pitting, and
that heat accelerates the infection. I have found that a calcareous sand
to which I have access (storing the potatoes in the same way as is usual
for gardeners to store carrots), keeps the potatoes separate, the pits
cool, and prevents infection.
ZETLAND
No. 43.—Mr Duncan of Tow,
15th February 1847.
The potatoes in the
district around me, my own inclusive, were perfectly unscathed till about
the 12th of August. They were looking beautiful, and we had all begun to
take a few out of the ground for immediate use ; and I was so satisfied
with the appearance and quality of mine, that I was congratulating myself
upon the real store of fine potatoes we should have for winter
consumption. About this time it was reported that the disease had appeared
in the southern parts of the parish of Dunrossness, about 12 or 15 miles
distant from us in a southerly direction, but which did not alarm me much,
as, having escaped its attack in former years, I thought I might do so
again. In a few days, however, I was told that my nearest neighbour,
immediately on the south of me, had observed that his potatoes were in an
unsound state. I went directly to look at them, and found that a portion
of them was completely destroyed, and that the leaves of the rest were all
becoming brown-spotted. Till now, mine continued to look well; but being
told at length by a gentleman who had noticed them more particularly than
I had done, that they too were affected, I went and examined them, when I
found the gentleman's report to be too true. The disease was then
discovered to have spread over the whole district, no part escaping; and,
in a short time, nothing was left of the shaws but the stems, blossoms and
leaves having all disappeared together. The weather was intensely hot at
the time, and continued so for some time after—the wind light, and,
according to my present impression, in the southern quarter of the sky,
though at this distance of time I am unable to speak with certainty on the
point.
What I have thus stated
with regard to appearances in this district, will apply, with little
variation, to the whole of the Zetland Islands. The potato crop every
where suffered in the same way, and from the same cause, whatever that
cause might be; but whether the agency of the wind may be supposed to have
had any influence in spreading the disease, is a point which I must leave
to others to determine. The solitary fact which I have mentioned, even
supposing the wind to have been blowing from south to north at the time,
seems to prove nothing to the purpose; as, about the same time that the
disease manifested itself in Dunrossness, reports were in circulation that
it had also made its appearance in the parish of Tingwall, eight or ten
miles north of this district. In fact, it is a matter of doubt to say
where it began, as it seems to have overspread the whole group of islands
at once.
The tubers when examined
had the appearance, as I formerly stated, as if they had been scorched
with fire, and when boiled whole, emitted an offensive smell. The disease
had not, however, in the majority of cases, carried its effects into the
centre of the potato; and when the damaged parts were removed, what
remained was as fine as could be wished.
The refuse, which served
for feeding pigs and poultry, was readily eaten by them, and found to
agree. The parts underneath, where the skin presented the scorched
appearance above described, were blackened, but there was no absolute
rottenness; on the contrary, the damaged parts felt rather hard and dry.
In some cases the injury had gone deeper into the potato than a third—so
deep, indeed, as to destroy it altogether. It is quite common, after the
potato—the portion of it deemed fit for use—has been boiled, to observe
dark-coloured lines, terminating each in a point, extending inwards from
the circumference, where the disease had established itself towards the
centre, as if they had been formed with a small-pointed instrument, with
some sort of colouring matter upon it.
I may now mention, from
what I have seen, that the disease, in my humble opinion, has not taken
its rise from any bad quality in the potato itself, but has been owing
entirely to external causes, either proceeding from the earth-insects or
the atmosphere, but which of these I must leave it to the learned to
determine. Some ascribe it to the extreme heat; but in this opinion I
cannot agree, as we have experienced as warm seasons before, without any
injurious effects to the potato crop.
All sorts of potatoes seem
to be cultivated here in a mixed form, chiefly— though I am unable to
distinguish many of them by the names by which they are known elsewhere. I
think I mentioned formerly there being among some of mine which I raised
in the end of harvest, a few of a pale red colour, with patches of white
upon them, particularly about the eyes, which had not taken the disease,
and made a selection of them, with the view of preserving them for seed
this present season, but unfortunately they were lost. I have, however,
obtained possession of a few again; and, if an opportunity offer, it is
possible I may take the liberty of sending the Society a sample of them.
Though grown among the diseased ones, they remained uninjured. My only
regret is, that I have extremely few of them.
Through the winter I
happened to have occasion to see Mr Mathewson, the schoolmaster of Yell,
who had lately returned from the island of Unst, and who informed me, on
my mentioning to him the discovery which I had made with regard to my
white-eyed potatoes, that he knew a man in Unst who had all his of this
description, and that he had not lost one of them last season. I
afterwards wrote to him to make further inquiries, and let me know how the
case really stood, and lately I received from him the very interesting
letter which is herewith sent, and from which it appeared that Bunt's
potatoes (for such is the man's name) are of the same sort as mine, to
which I have already referred. Where they came from originally is more
than I can tell; but if they possess the peculiar quality of resisting the
disease, as I cannot doubt they do, they are a great acquisition to those
who are fortunate enough to possess them. Some of my neighbours, to whom I
showed mine, said their experience coincided exactly with my own.
I scarcely know of any
attempts being made here to raise potatoes from the seeds; and it may be
stated generally, that those in use now among us are the same, with little
variation, that have been used for time out of mind. In wet soils, I have
heard—and I believe it—that the potatoes have suffered less than in the
dry, though they have not escaped it altogether; and, in some few
localities, even where the soil was rich and dry, the injurious effects
have not been so severely felt, as in others of the same description.
Nothing can be inferred from the mode of manuring the land intended for
potatoes; as some people apply manure, and others, and by far the greater
number in this district, none—myself excepted. At any rate, the mode of
culture was the same last season that it had been from time immemorial;
and I may add, that no where, so far as I know, are greater pains taken
upon the care and cultivation of the potato crop than in Zetland.
The usual mode of storing
potatoes here is to place them in pits in the earth. I warned the people
against continuing this plan this last season, as I was apprehensive they
would take heat and rot; and the event has shown that my anticipations
were well founded, as there are few now left, either for food or seed. The
people, for want of other means of preserving them, were compelled to act
as they had done before, and they are the sufferers. The few individuals
who were at the pains to separate the healthy tubers from the others,
have, I understand, succeeded in preserving them, though they are
comparatively few in number who have been thus fortunate.
I raised some of mine in
the end of harvest: and though I dried them in the sun, when laid in a
heap—though laid in a cool place—they immediately took heat, and had to be
taken out and dried a second time, before they were considered out of
danger. The rest were left in the ground (it happening to bo enclosed) ;
and though I am not prepared to say that they are better now than they
were at the end of harvest, neither can I say that they are any worse. |