THE 
GARDENERS' 
CHRONICLE. 
(Fen. 21, 
mere breathing upon it sets it in action, and it-has 
the great merit of indicating at all times by its index 
hand exactly what the state of the air may be... We 
regard it as the very best instrument that has been 
introduced into notice for a Jong time, so far as 
practical gardening is concerned. It may not be, 
and probably is not, fit for very strict scientific pur- 
poses, but it is amply sufficient for every object of 
horticulture. 
In the official report on the Poraro Crop, by 
the late Irish commission, dated Nov. 7, 1845 (see 
p. 767, 1845), is the following paragraph. “ It has 
also been ascertained by actual experiments that 
Potatoes, though diseased, will grow and produce 
apparently healthy plants.” ^ Nevertheless, the 
commissioners thought it imprudent to recommend 
the employment of such Potatoes, “except by way 
of experiment ;” thinking, no doubt, that the evi- 
dence in their favour was inconclusive. We greatly 
regret to state that the event has justified their 
caution. We are nowin a condition to announce posi- 
tively that although diseased Potatoes will produce 
plants whieh for a few weeks appear to be healthy, 
yet that they will not remain so, and that DISEASED 
SETS WILL PERPETUATE DISEASE. 
It was stated at the meeting of the Horticultural 
Society, on Tuesday last, that it had been for some 
time rumoured that the new Potato crop was again 
attacked in forcing-houses by the old disease ; that 
these rumours had become so'frequent as to cause 
strict inquiry to be made into their truth ; and that 
the result of that inquiry was a confirmation of the 
reports alluded to. Potatoes were produced from 
Mr. Barnes, gardener to Lady Rotts, at Bicton, 
in which the disease had manifested itself in a 
manner not to be mistaken ; first, by the appear- 
ance of a brown gangrene on the haulm under- 
ground and in the neighbourhood of the old tuber, 
and next by rotting blotches on the leaves. ‘These 
Potatoes had been planted in the autumn. In the 
month of January “they were as strongly and 
evenly above-ground as I ever saw a field of Pota- 
toes in May,” are Mr. Barnes's words. The disease 
was remarked upon taking up a portion for trans- 
planting to a hotbed for forcing. Of the samples 
produced to the meeting of the Horticultural So- 
ciety, one, and much the worst, was the produce of 
“rather badly affected tubers ;” in these the whole 
of the under-ground haulm was already gangrened, 
and brittle. Another sample, from tubers supposed 
to have been sound, also manifested the symptoms 
in putrifying blotches on the leaves, accompanied 
by the under-ground gangrene. 
In addition to this Devonshire evidence, it was 
men‘ioned that plants in the Garden of the Horti- 
cultural Society, examined the previous afternoon, 
were found in the same state, the under-groun 
haulm haying already begun to decay in blotches. 
It was added that these plants were also obtained 
from diseased tubers, planted for the express pur- 
pose of watching the progress of growth. No 
trace of fungi could in their instance be discovered | th 
on the decaying spaces after the most careful 
examination of some hours’ duration ; but a white 
mouldiness had manifested itseif on the stems sent 
up from Bicton. 
But this is not all. Upon-examining more care- 
fully the young Potatoes formed by the diseased 
séts, we found still further evidence of latent mischief. 
Some of Mr. Banwrs's Potatoes had formed 
tubers aud roots without haulm or foliage; they | 
were what are called in Cornwall “ Bobbin joans.” 
In' one of these the brown colour on the walls of 
the cells, the earliest symptom of disease, was al- 
ready appearing in numerous minute places, in the 
very centre of the young Potato [this Potato became 
ack after 24 hours’ exposure to air] ; others were 
ying on the surface, and one of them had already 
id away. We now, therefore, warn the 
that DISEASED SETS WILL PRODUCE A DISEASED 
Not a shadow of doubt remains upon that 
at unfortunately this intricate question is not 
settled by h an announcement. On the con- 
r us consideration remains behind. 
s involved in this question are so mighty 
must be content to- bear the reproaches 
which may be poured upon us if we hazard an 
3 y I I 
opinion which the result may not confirm. We 
venture then to declare thus early that GREAT DOUBTS 
AS TO THE FITNESS FOR SEED OF APPARENTLY 
ND POTATOES FROM DisEASED DISTRICTS.. That 
the remaining Potatoes of last year's crop are in an 
unusual condition is certain; they are more ex- 
citable; they will sprout much quicker than is 
gustomary ; at this early period Potatoes are found 
in a state of advanced growth when the pits are 
opened; and this has taken place much beyond 
what can be ascribed to the peculiar mildness of the 
season. In fact, the old tubers of last autumn 
began to grow in a few weeks after they became 
ripe or what seemed so; an event unknown in 
previous Potato culture. "Why this is we know 
not; nor shall we embarrass ourselves with 
enquiring whether it is owing to this or that 
chemical peculiarity. It may be very true that 
the Potatoes have formed unstable casein in- 
stead of stable albumen ; or some other ex- 
planation may be more correct. For us it is 
enough to know that the vitality of the Potato is 
affected. The living principle is changed; of that 
no doubt can exist; and such being the case it is 
much to be feared that the disease of last year will 
continue to appear until, or except where,the original 
constitution of the Potato is recovered. 
But we would not sound a note of alarm upon 
mere speculations, We grieve to announce that we 
have now before us evidence that confirms the view 
we have ventured to take. Among the Bicton Pota- 
toes above alluded to was one which the most prae- 
tised eye would, we think, have pronounced sound ; 
its skin was clear, its texture uniformly pale yellow, 
with no tendency to change colour when ex- 
posed to the air, and its surface had not a blemish, 
with the exception of a small very narrow short 
streak on one side, which seemed to have been 
the scratch of a fork. This Potato pushed 
vigorously ; its main stem is half an inch in 
diameter ; it must have shown all the symptoms of 
the most robust health; and yet gangrene has 
attacked the haulm just above the tuber, and the 
usual blotchings have appeared upon the leaves. 
This Potato plant is unequivocally diseased, 
We will suppose that some trace of disease could 
have been found in this Potato, by cutting it into 
thin slices, though we have failed to discover them 
by that process, Admitting this, yet it is perfectly 
clear that if healthy Potatoes can only be discovered 
by such a process, THE CROP OF NEXT SEASON IS 
DOOMED wherever sets from diseased fields are 
employed. 
We therefore warn the country,in the most empha- 
| tic language that words are capable of conveying, to 
think well of what is coming ; to plant no Potatoes 
to which suspicion aftaches ; and, ifsets from unin- 
fected districts cannot be procured, to crop their land 
with something else. There ean now be no doubt 
that in the absence of such precautions there is no 
security for the Potato crop of 1846. 
[Since writing the above we have received con- 
firmation of our worst fears. Mr. EnniNGTON, gr. 
to Sir Partie Ecerron, at Oulton, in Cheshire, 
writes that in a garden near him “ the Early Kidney 
Potatoes in frames are totally destroyed.” He 
adds that he “saw the frames last week, and the 
stems have mortified from the leaves downwards, 
exactly as they did in the open fields last September.” 
| Mr. James Curai, of Camberwell, informs us 
at Mr. Hare, a market-gardener at Ware, in 
| Hertfordshire, has had his early Potatoes attacked 
with last year's disease ; that “half his crop, 
amounting to about 60 lights, is gone ;” that the 
plants “ were looking well, and about 8 inches high, 
and all at once they were attacked." Mr. Hatr, 
florist, Stockwell, saw these Potatoes, and autho- 
| rises Mr. Curar to say so; the owner was dust- 
ing them with lime. 
We have received a sample of Potatoes from Mr. 
Mirsonw, of Thorpfield, near Thirsk, just taken 
out of the pits, and “quite sound as far as he can 
judge,” in which indeed there is not the smallest 
outward sign of decay, and yet we find every one 
marked with the disease upon cutting into them. 
We are also informed that the forced Potatoes at 
Col. Wywpuaw's, at Petworth, have proved to be 
diseased, although great care was taken in picking 
out what appeared to be sound sets, Of this last 
case, however, we have no certain knowledge 
as yet.] 
upon the effects on plants of air in rapid motion. 
ENTOMOLOGY. * 
Czrnus Pyaw Eus (the Corn Saw.fty).— When atten- 
tionis once called to a neglected subject, it is almost 
ineredible what light is soon thrown upon it. The eco- 
nomy of this insect was unknown in England a few years 
back, but the French naturalists and agriculturists 
lately recorded their researches, and its history had 
scarcely been published in the “ Journal of the Royal 
Agricultural Society," when a gentleman at Cranford 
discovered portions of his Wheat crop infested by the 
Cephus; He found that some straws readily broke off 
towards the ground ; and about the middle of last 
August he showed me several which he had slit open 
(Fig. 1) with the larvec and their cases in ‘them, about 
an inch and a half from the root, and just above a knot 
was a larva lying straight within a fine silky film (Fig.2), 
with some dung below it, and a farinaceous substance 
resembling dry paste above it. “It soon made its way 
out, from being disturbed, and laid in the curved po- 
sition shown at Fig, 3. It was yellower than represented 
M. Guerin, more wrinkled, the head was not so 
brown, but that might be owing to its not being quite 
matured, and there were four fleshy protuberances, the 
analogues of abdominal feet, which were very distinct 
when the animal was irritated : pectoral feet it hadjnone. 
It appears that Wheat crops are not commonly, 
attacked by the Cephus in France, but Rye is some- 
times so extensively affected, that a field appears at 
harvest time as if it had been traversed by sportsmen 
and dogs in every direction, The infested plants may 
be readily detected a week or two before harvest by the 
whitened and straight ears being elevated above the 
others, and appearing perfectly matured, forming a 
striking contrast with the surrounding green crop, the 
ears of which ave full and drooping, whilst the others 
are either empty, or contain only a few shrivelled horn 
grains. The maggots inhabiting the straws live through 
the winter in a fine transparent case of the closest 
texture, and in all probability impervious to the air ; 
they have been observed transformed into the pupa 
state at the end of March: these have hatched the 
beginning of April; but oftener at the end of May, 
before the Rye and Wheat are in flower, but I usually 
find the Cephus in corn-fields in June, and in the first 
week of July the 
females only are 
abundant. After 
pairing, this sex 
pierces the stalk 
below the first knot, 
and deposits an egg 
in the interior, or 
else later in the 
year the eggs are 
laid upon the stem 
immediately below 
tender straw ;- it 
subsequently .per- 
forates. the knot 
and passes higher 
up, sometimes tra- 
versing all the 
joints. When full 
grown it returns, 
and arriving at the 
base of the straw, itZeuts it down level with the ground 
at the time of harvest. It then enters the stump of 
the Ryea little below the soil,{wliere it closes its tunnel 
with a stopper of sawdust and excrement, encloses 
itself in a transparent cocoon a great deal larger than 
itself (fig. 4), and there remains for eight months.” 
The straws being cut circularly on the inside by the 
maggot which is furnished with strong jaws, they die, 
andare readily broken off by the wind, so that the fly 
when it hatches can, without any difficulty, make its 
escape 
Cephus pygmeeus is of a shining black colour; it has. 
prominent eyes, and three ocelli on the crown; the an- 
tenne are rather long, slender, slightly clavate, and 
composed of 21 joints ; the mouth, in the male, including 
the powerful jaws, is bright yellow, a spot on the 
nose and the inner margin of the eyes are of the same 
colour ; the abdomen is sessile, rather long, slender, and 
slightly compressed, at the base is a yellow membrane, 
there are yellow spots on the sides of the first and second 
segments, and a dot on the back of the latter ; the third 
and fifth segments have broad yellow margins, the sixth 
has anarrow one, forming spotson the sides and back, and 
the apex is yellow ; the wings are transparent and iri- 
descent, with many cells, the costa and stigma are yel- 
lowish-brown, and all the nervures are fine and brown ; 
the legs are bright yellow, including the coxæ and 
trochanters, but they, as well as the thighs, have black 
stripes on the outside ; the hinder tibim are spurred 
at the apex, with another pair of spurs below the middle ; 
they are brown on the outside, as well as the 5-jointed . 
tarsi; the claws are bifid with little pulvilli between 
them (fig. 5, the eross lines showing the natural dimen- 
sions). The female is larger, the palpi and sides of 
the jaws only are yellow ; the abdomen is rather stouter 
and shorter, the yellow spots on the two basal joints 
are either very minute or obliterated, the margin of 
the 6th is less apparent, and the bands are more ofa 
sulphur colour ; the apex is sloped off obliquely, and 
receives a black ovipositor, which is but slightly exposed; 
the wings are rather smoky ; the legs are ochreous, 
the coxre, trochanters, and thighs black, excepting the 
extremity of the latter above; the hinder. tibiæ are 
brown outside, and the four posterior tarsi are of the 
same colour. 
These flies resort to flowers in corn-fields, Grass in 
woods, and Umbelliferee and Composite on banks and 
roadsides, The straws containing the larvee may be 
detected after harvest by a little attention, the short 
pieces of stubble being cut very horizontally by them. 
They undoubtedly cause some’ mischief, as the ears of 
the infested stems are either steril, or contain only a 
small number of shrivelled grains. Burning the stubble 
seems to be the best means of extirpating the Cephus, 
but there is an Ichneumon named Pachymerus calci- 
* Vide M. Dugaigneau’s and M. Herperi's Memoirs, 
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