98 
AMERICAN AGRICULTURIST. 
this head, that the only conclusion which can 
be drawn is, that frequent repetition of the crop 
exercises no particular influence. The disease 
was, in several instances, very severe on land 
where turnips had never been raised. 
7 th. Occurrence of insects on the plants. —On 
this point, the information is also very conflict¬ 
ing. But although the majority of the obser¬ 
vers state postively that no insects were present, 
this does not outweigh the testimony of those, 
who were, perhaps, more careful observers, 
who found evidences of insects, and who are in 
the belief that the disease may be produced, like 
galls on the oak, by the presence of the larvae 
of some insects. One gentleman, Mr. M’Turk, of 
Hastings Hall, presented a report on this sub¬ 
ject, which is very interesting, and we quote a 
part of it in his own words : 
On a minute examination of the disease, where 
fully developed, I invariably found evidence of 
insect life, and, when only in the incipient stage, 
it appeared as if the circular tissue had been 
ruptured in minute patches over the substance 
of the galls or tubercles—these patches extend 
in size till the} 7 run to each other, and are at 
first of a blackish color, but in the course of 
time acquire a brownish shade, which 1 regard 
as merely the progress of putrefaction. I be¬ 
lieve that these blackish patches are very gen¬ 
erally occasioned by the attacks of insects, 
when an insect, either from instinct or to satisfy 
its wants, in the first instance pierces the root. 
It then deposits an egg, scoops out another hole, 
and another egg is deposited. These holes are 
sometimes close to one another, or at short dis¬ 
tances ; and although the skin of the root has 
only been pierced in the first instance, and a 
lodging for the egg found in the substance of the 
root, by a law common to every species of life, 
the plant covers over the puncture by a deposit 
of fresh matter, a tubercle is formed, and, as 
the insect continues its operations along thecon- 
tigious portions of the root, or is joined by 
other insects in the like operations, a series of 
galls or tubercles are formed. The living ener¬ 
gies of the plant are then still further impaired, 
putrefaction in some of the earlier-formed tu¬ 
bercles commences, and this most commonly at 
the time when the eggs deposited have arrived 
at the larvae stage. The maggots or grubs thus 
produced, live on the putrid matter around them, 
and eat their way to the surface, forming an 
outlet by which they have communication with 
the soil and air, but still continue to feed on the 
decayed substance of the root, which at last as¬ 
sumes a honey-comb appearance from the con¬ 
sumption of the more putrid matter, and then 
becomes a fit receptacle for the chrysalides, 
when that stage of their existence arrives. But 
in cases where there was little putridity, I have 
found many instances in which a maggot has 
taken a different direction, and continued its 
course into the solid tuber till the time arrived 
for its transformation, or when it could proceed 
no further. It seems then to have surrendered 
itself, and the change into chrysalis taken place, 
the same as, under more favorable circum¬ 
stances, for its entering upon insect life. The 
ravages of these maggots are not confined to 
the putrid matter of the finger and toe excres¬ 
cence, but the unhealthy state of the plants 
renders the fibrous roots an easy prey to them 
and a great variety of the beetle tribe, and their 
larvm, which infest the soil. Nor is the depre¬ 
dation of these tribes confined to the fibrous 
roots, they penetrate the interior in great num¬ 
bers, and of many different kinds, as far as pu¬ 
trid matter is to be found, the turnip thus becom¬ 
ing a means by which its deadliest foes are 
nourished, increased, and perpetuated; and I 
believe it is from this cause that the disease is 
in general most prevalent in those farms (other 
things being alike) where turnips have been 
longest and most frequently cultivated. 
Query ? May not some clue to the potato 
rot be suggested in the above quotation ? 
We pass over the answers to the several 
other inquiries, which are so contradictory as to 
give little information, or are alluded to in the 
General Conclusions. —We will here give in 
full, the general conclusions of the committee, 
which are as follows: 
Such are the results of the inquiries made 
among some of the most skilful farmers in all 
parts of Scotland, results which, as it will be at 
once apparent, are of a very conflicting nature— 
much more so than could possibly have been 
anticipated. It appears, indeed, that not only 
do remarkable differences of opinion exist 
among different persons, but in some instances 
an individual reporter informs us that he had 
arrived at certain definite conclusions, of which 
the experience of later years had led him to 
doubt the accuracy. Many of these discrepan¬ 
cies are no doubt due to climatic differences, 
and might probably meet with a satisfactory 
explanation, if we possessed definite informa¬ 
tion regarding the meteorological phenomena of 
the districts in which they were observed; but 
others are of the mostinexplicable character. It 
is very difficult to deduce, from among these con¬ 
flicting statements, any conclusions which can 
be considered altogether beyond cavil; but we 
shall endeavor to state at least such as appear 
to us fair and legitimate inferences, from the 
consideration of all the facts, both theoretical 
and practical, which have been accumulated. 
1st. It is unquestionable that the disease is 
not due to any chemical change in the composi¬ 
tion of the soil. It is obvious, however, that 
its physical characters, though not the cause of 
the disease, influence in some way or other its 
development. Thus it is unequivocally made 
out that the disease occurs far more frequently, 
and far more severely, on light soils than on 
heavy, and that the stiffer clays seem to pro¬ 
duce turnips in which it is rarely observed. 
2d. The disease is not dependent on any 
chemical change having taken place in the plant 
itself, but the changes observed are a conse¬ 
quence of diseased action. 
3d. That, as far as can be at present seen, the 
most probable explanation is that which attri¬ 
butes the disease to the attacks of insects. 
This view, and the mode in which the insect 
appears to make its attack, have been detailed 
at some length already, in the words of Mr. 
M’Turk, who has described the whole matter 
with the greatest clearness. It will not, of 
course, be supposed that we can assert with pos¬ 
itive certainty that insects are the invariable 
cause of the disease, for many of the reporters 
state that they have never observed any. It 
must be observed, however, that this is nega¬ 
tive evidence only; and in some cases, no doubt, 
the failure to observe insects may with justice 
be attributed to the observations not having 
been properly made. It is not to be expected 
that the effects are produced by insects infest¬ 
ing the leaves of the plant, but, as has been be¬ 
fore observed, it must be due to their attacking 
the root, and depositing their eggs in punctures 
in its skin. Mr. M’Turk has fully explained all 
this, and Mr. Sanderson has stated that he has 
invariably found a small worm or grub, on cut¬ 
ting open the excrescences in their early stage. 
In fact, if insects are to be sought for, it ought 
to be by cutting open the fingers and toes, and 
carefully examining them in all directions in the 
earlier stages of their growth, because, in most 
instances, the caterpillar produced from the egg, 
which we believe to be deposited in the puncture, 
according to an established law of insect life, eats 
its way outwards to the external air. I am even 
inclined to believe that the putrefaction observed 
in the latter stage of the disease is due to the 
communication made between the air and the 
interior of the bulb, the juice of the turnip be¬ 
coming partially extravasated, and decomposi¬ 
tion being set up in consequence. The opinion 
that the disease is due to insect life, appears to 
me to derive confirmation from the fact that 
land becomes, so to speak, infected; so that, 
when the disease has once made its appearance, 
its tendency is to extend, and it is only eradi¬ 
cated by some special treatment. Numerous 
remarkable instances have been communicated 
to me, in which the disease was manifestly pro¬ 
duced by a sort of infection. Mr. Elliot states 
that he has often observed that, if diseased tur¬ 
nips be stored during winter on a stubble field 
intended for turnips next year, the disease in¬ 
variably destroys the crop in those parts. Mr. 
Wilson, Freeland, mentions a case having oc¬ 
curred on Lord Blantyre’s farm, in which dis¬ 
eased turnips were applied as manure to the 
wheat crop, and the disease afterwards made its 
appearance on the part of the field so manured. 
Mr. Fortune, of Muircambus, gives a similar 
statement as having been observed on two dif¬ 
ferent occasions on his farm; and Mr. Finnie 
observed, on a field of his in which turnips had 
been partly removed and partly eaten off with 
sheep, that the former was comparatively free 
of disease the next time it was under turnip, 
and the latter portion severely affected. Nu¬ 
merous similar facts have been mentioned to 
me, so that there can be no doubt about the ac¬ 
curacy of the observation. Now, the most in¬ 
telligible explanation of this fact is, that the in¬ 
sects, once introduced into the soil, remained 
there, and attacked the subsequent crop. We 
know that when insects pass into the chrysalis 
state, they frequently remain for years in that 
form ; and thus it is easy to conceive that they 
may have lain dormant in these cases, and in 
passing into the perfect insect have deposited 
their eggs on the young plant. It would also 
explain the fact that, when the disease appears 
in a district, it remains permanently in it, unless 
some means of eradicating it are taken. 
-ith. It appears that the disease may in most 
instances, though not in all, be prevented by 
the liberal use of lime, which must be applied 
one or two years previous to the turnip. 
5th. If this disease be really produced by 
the attacks of insects, it is worthy of inquiry 
whether lime may not produce its good effects 
by destroying them. If so, there must be other 
modes in which this could be effected equally 
well, and with a less expenditure. Several sub¬ 
stances have been used for destroying insects, 
such as tar, tar oil, and the like. Salt has 
also been employed in some cases with effect, 
and one or two instances arc mentioned in 
which it has proved of use to the turnip. These, 
and similar methods of treatment, are certainly 
deserving of more extended trial. 
-«« «- 
HOY/ TO USE GUANO. 
We have remarked on this subject frequently, 
but as too much can scarcely be said on a topic 
of so much importance, we subjoin the following 
concise directions from th a Marie Lane L.vpress. 
First.— Never mix it with any thing; all, 
lime, compost, ashes, and similar ingredients, 
too often contain enough caustic alkali to drive 
off the ammoniacal parts, before the soil can 
surround and absorb them. A vast amount of 
mischief and loss often follows this sad mistake. 
If they could apply it alone, the soil can best 
adapt it for plants. ■ 
Second. —Mix as much as possible with the 
soil, not too deeply, but plow it in after sowing 
it broadcast, unless it be for beans, or drilled 
and ridged crops, when it may be sown on the 
surface before the ridges are made. 
Third. —If applied as a top-dressing, always 
apply it, if possible, before rain, or when snow 
is on the ground; and if on arable land, har¬ 
row, hoe or scuffle, if possible, immediately 
after the operation. 
Fourth. —The best mode to apply it is by wa¬ 
ter. A slight solution of it is by far the most 
powerful and speedy application. 
Fifth. —If sowed with drilled grain, or in¬ 
deed any seed whatever, it should never come 
in contact. It is not a bad plan to sow broad¬ 
cast, after the corn-drill, and then harrow, as it 
