760 
July 27, 1895. 
THE GARDENING WORLD 
HINTS FOR AMATEURS. 
Insect Pests in the Greenhouse. 
While it is quite true that in very many instances 
the amateur gardener lags some distance behind the 
professional, and while the latter, with very few 
exceptions, fails entirely to understand the difficul¬ 
ties and grievances of the former, in one matter at 
least they are common sufferers, and are called upon 
to contend with the same enemies in the shape of 
the numerous insect pests that attack the plants 
under their charge. If anything, perhaps, the 
amateur is the greatest sufferer in this respect, from 
the fact that his plants, not being quite so well looked 
after as those of the more experienced man, and 
hence not in such vigorous health, are more likely to 
suffer from insect attacks. Another fact that pro¬ 
bably exercises not a little effect upon the cleanliness 
of the plants is that in the comparatively small 
houses of the amateur is to be seen a heterogeneous 
collection of subjects, often stood much closer 
together than they ought to be, with the result that, 
as it is impossible to manage the house in such a 
way as to suit them all, many of them suffer in 
general health, insects of one or more kinds effect a 
lodgment and still further impair their constitution 
and appearance. A few hints, therefore, as to the 
treatment of plants infested by some of the various 
kinds of insects which prey upon our favourite 
flowers may be of service to those who are sorely 
plagued in this way. 
It may be stated at the outset that the old motto 
of prevention being better than cure applies here 
with singular force. By taking every care to keep 
the plants in good health the danger of their being 
badly attacked by insects is reduced to a minimum. 
Cleanliness in the house itself is likewise a 
most important point, and one about which we 
may say a few words with advantage. No matter 
what the kind of house is, whether span, hip-roofed, 
or lean-to, whether big or little, it is sure to contain 
a greater or less number of nooks and crannies which 
afford excellent harbour for insects. Several times 
a year, therefore, a thorough clearing should be 
given, the house cleared entirely, and the glass and 
woodwork well washed. By means of a small brush 
the corners should then be anointed with neat 
petroleum. If the house is a lean-to the back wall 
should be whitewashed at least once a year. This 
gives the advantage of a fair start, and if ordinary 
care is taken not to bring in dirty plants half the 
battle is won. By keeping a bright look-out sub¬ 
sequently and taking remedial measures before the 
little pests have obtained a footing everything may 
be kept clean and tidy with but comparatively little 
trouble. 
Mealy Bug. 
Although one of the commonest of insects this is 
certainly not nearly so destructive as many of the 
rest. True, its appearance does not in any way 
enhance the beauty of the plants, especially when 
seen hanging, as it sometimes is, in delicate festoons 
from leaf and branch. It is in the warmer houses 
that it usually makes itself apparent in such large 
numbers, the tropical heat appearing to suit its 
particular proclivities to a nicety. In the green¬ 
house, however, it does not multiply with anything 
like the freedom it does in the stove, neither does it 
usually infest the smaller plants to any serious 
extent. It often does take up its abode among the 
larger plants, climbers especially, and Tacsonias, 
Passifloras, and Lapagerias need to be gone over 
now and again and cleaned. With the two former 
subjects the thick growths made, constitute a fair 
refuge for them, particularly as it is not possible to 
disturb them much yet. The weaker growths in 
the case of Tacsonias may, however, be cut out and 
the remainder syringed with a mixture of petroleum 
and warm water in the proportions of a wine-glassful 
of the former to a couple of gallons of soft water. 
The mixture must be kept constantly stirred all the 
time it is being applied, otherwise the petroleum, 
which never mixes readily with the water, 
will separate out and float upon the top. It is a 
good plan for two syringes to be kept at work, the 
one being used for applying the mixture to the 
infected subjects, and the other to keep it constantly 
stirred meanwhile. 
Snowy Fly. 
This, a very common fly among all kinds of plants, may 
be readily distinguished by its being of a silvery white¬ 
ness. It is very partial indeed to Tomatos, and is 
usually present upon them in greater or less numbers. 
Spreading from thence on to Ferns and other plants 
that may be beneath them it quickly multiplies and 
is exceedingly difficult to get rid of. Indeed, so 
tenacious is it of life that a painstaking amateur, 
who, finding his house overrun with it, and having 
made several ineffectual attempts to rid his plants of 
it, applied to a neighbouring expert for advice and 
assistance, received the very discouraging reply that 
he was to fumigate his house morning and night 
every day for six week 1 :, and perhaps half of it would 
be dead then. About the best method of dealing with 
it that we have practised is to dissolve a piece of soft 
soap about the size of a Walnut with a little petroleum 
in warm water, thereby making a nice washing 
mixture. Wring the sponge until it is nicely damp, 
when on applying it to the leaves the flies will stick 
thereto, and may be drowned in the washing solu¬ 
tion. 
Red Spider. 
There can be no doubt that if once allowed to gain 
a foothold, Red Spider is one of the most mis¬ 
chievous of insects, for once it does effect a lodge¬ 
ment goodbye to the hopes of obtaining good plants 
unless it is speedily ejected. The insects themselves 
are very minute and not easily discernible ; not so, 
however, their effects. Leaves turn first yellow, and 
then brown, as if blighted by the breath of some 
noxious gas, and finally drop off, leaving the plants 
in a crippled condition In a dry hot summer like the 
present, Red Spider is almost sure to make its appear¬ 
ance somewhere unless special care is taken. On no 
account must the plants be allowed to get dry at the 
roots or a parched and arid atmosphere to obtain, for 
these conditions are almost invariably followed by 
bad attacks of this harmful spider. By usiDg the 
syringe frequently and well it may easily be kept in 
check ; whilst even after it has made its appearance, 
clear water forcibly applied is the best way to get rid 
of it again. 
Thrips. 
These are very commonly met with both in warm 
and cool houses, and their presence is invariably 
attended by disastrous consequences to the health of 
the plants, the leaves of which present a spotted and 
mottled appearance very unsightly to behold. 
Among Ferns, particularly, they play a great deal of 
havoc during the summer months, and as they 
multiply so rapidly are very much to be dreaded. 
The best way of dealing with them is by fumigation 
with tobacco paper or rag. In fumigation, a good 
deal of care is necessary or the remedy will prove 
worse than the disease. The atmosphere of the 
house must be kept as dry as possible, no water being 
allowed to stand upon the foliage. It must be con¬ 
ducted, moreover, before the sun has acquired very 
much power in the morning, and when done in the 
evening it should have sunk pretty low; for, if not, 
its rays beating down upon the closed up house will 
raise the temperature to a height that cannot fail to 
be injurious to the occupants. If the house possesses 
blinds these may be lowered when the fumigator is 
set alight, for a great deal of the smoke is thus 
prevented from escaping. Another point that must 
receive attention is that the fumigator is not allowed 
to stand directly beneath any tall plants or over¬ 
hanging baskets or the hot fumes will be sure to 
harm the delicate foliage. Above all, watch the 
burning tobacco very closely to prevent it from 
flaring, and on no account fill the house too full of 
smoke. It is far better to smoke three or four times 
lightly in quick succession than it is to fumigate 
once very heavily ; for by the former method the 
insects are far more likely to be destroyed, and the 
plants themselves stand in much less danger of 
sustaining injury. 
Scale. 
With this the list of the commonest insect pests is 
complete, and although Scale is by no means a 
desirable adjunct to plant life it is not nearly so 
much to be dreaded as Thrips or Red Spider. A 
washing mixture composed of a weak solution of 
lemon oil may be used. A gentle pressure with the 
thumb nail will be necessary to remove the Scale 
which usually adheres very closely, the place it 
covered being afterwards washed with the insecti¬ 
cide. —Rex. 
Fruit trees by the highways.—On the Continent the 
practice of planting fruit trees and nut trees along 
the sides of the highways, instead of trees that 
merely afford shade, has been largely adopted. 
THE EFFECT OF DARKNESS ON THE 
FORM OF PLANTS. 
At the meeting of the Royal Horticultural Society 
on 9th July, Mr. Francis Darwin gave a very 
interesting and instructive lecture upon the effect of 
darkness upon the form of plants, Dr. Masters 
presiding and a goodly number of listeners being 
present. The lecturer prefaced his remarks by saying 
that the precise effect that loDg continued darkness 
exercised upon the appearance of plants was so far 
very much a matter of conjecture as physiologists 
stood very much in need of more facts upon which 
to work, and his principal reason for bringing the 
subject thus prominently before their notice was 
that he might excite the interests of practical horti¬ 
culturists in it and induce them to make experi¬ 
ments, which they of all others were the best 
qualified to do and which might result in the 
throwing of a lot of light upon a hitherto little known 
because little studied branch of research. 
Mr. Darwin then went on to say that everybody 
knew what the appearance of plants which had been 
grown in a dark place was like, especially with 
regard to the difference of colour; how the white 
stems and sickly yellow leaves indicated that some, 
thing was wrong. Eut it was of the change of shape 
in the body of the plants that he wished more 
particularly to deal. One of the commonest forms of 
deformity caused by the absence of light during the 
growth of any plant was that illustrated by the 
growth of a Potato in a dark cellar, viz. greatly 
elongated stems and marked dwarfness or sup¬ 
pression of the leaves. 
Another equally common form was that exemplified 
by the sprouting of cereals in a dark room. Here 
an extreme lengthening of the leaves was manifest. 
Stephen Hales, who might be regarded as the father 
of English physiologists, was of opinion that light 
acted as a direct food to the plant so important was 
its presence to its welfare. Here the lecturer said 
he was reminded of the philosopher in " Gulliver's 
Travels” whopossessed a government grant for manu¬ 
facturing Cucumbers out of sunshine ; a state of affairs 
which though it sounded laughable enough, was yet 
perhaps not so very much awry. Professor Vines 
had pointed out that to keep a plant in darkness was 
not the only way of starving it, for this conld as 
easily be done by keeping it in an atmosphere 
deprived of carbon dioxide. Experiments have been 
made with seedlings grown in darkness and exposed 
for a very short time each day to the light, but not 
long enough to enable them to develop chlorophyll. 
Even this short exposure was sufficient however to 
prevent deformity. The idea that etiolation was 
simply a pathological state of things was now given 
but little credence to, except by Professor Sachs who 
still held this view. Following in the footsteps 
of other eminent botanists Mr. Darwin was of 
opinion that it was simply an adaptation on the part of 
the plant to changed surroundings, a response to a 
stimulus, an attempt to get out of the difficulties 
which the change of environment had placed it in. 
As an illustration of what he meant he might quote 
the case of rickets in young children, where the 
outward evidences of the disease, the crooked spine 
and protuberances on wrists and ribs did not put the 
child in the best condition for grappling with it and 
finally overcoming it. In examining the elongated 
stem and the dwarf stunted leaves of a Potato 
growing in darkness it would on the contrary be 
found that these conditions did put the plant in the 
best way of overcoming its difficulties. The plant, 
knowing that its existence would be greatly 
endangered unless it could reach the light and there 
throw out its leaves, devotes all its energy to the 
work of producing an elongated stem or stems which 
shall penetrate into the influence of the all-important 
light. Take another instance, that of a seedling 
Bean growing in a dark room ; in a normal state 
when germinating in the open air the plumule forms 
a hook as it were, which enables it to push through 
the soil without fear of the delicate leaves at the tip 
being injured. When growing in a dark room with¬ 
out encountering the resistance of the soil that it has 
to contend with in the open air we should 
naturally expect that it would straighten itself, but 
this it does not do, for it is waiting for a signal—the 
signal of light to which alone it will respond. 
The flower of the Crocus is also extremely sensi¬ 
tive, fer upon a slight change of temperature, caused 
perhaps by a cloud obscuring the sun, a slight 
movement is to be observed in the petals, which 
