December 23, 1893. 
263 
THE GARDENING WORLD. 
forgotten; the dwarf compact habit and free- 
flowering properties of the species make them 
valuable plants in the rock garden. 
In connection with herbaceous and Alpine plants, 
there are many dwarf-growing shrubs, both flower¬ 
ing and fine foliage kinds, that are worthy a place 
in the rock garden. The seedling Pernettyas, where 
they can have a partially shaded corner, are 
attractive when well berried. Daphne Mezereum 
is another plant worthy of a place, and the variety 
of white and coloured flowers and red and yellow 
berries makes them worthy of being more often seen 
than they are. Cydonia japonica and its varieties 
are worth a place. Kalmia latifolia and K. angusti- 
folia are worth having; the former, although not 
strictly a spring-flowering plant, is worth a sheltered 
place in the rock garden. Andromeda floribunda. 
Erica carnea, and E. c. alba must not be forgotten. 
Here I must draw to a close; the extent of the 
subject is too much for a short paper like this. My 
intention was to draw your notice to a few of the 
best plants suitable for this class of work, and in 
doing so to help to draw attention to a more natural 
system of arrangement in our flower gardens.— 
Alex. Wright. 
THE APPLE SUCKER.* 
The Apple sucker (Psylla Mali, Forster) is fre¬ 
quently the unsuspected cause of much injury to 
the Apple crop. Its larvae, which cause the mischief, 
are so small, and so closely concealed in the buds, 
that they may be easily passed over by casual 
observers. Their action upon the flower and leaf 
buds is often confounded with that of the cater¬ 
pillars of the winter-moth, and the larvae of the 
Apple-bud weevil, which appear at about the same 
time. 
The Psylla larvae may be seen by careful inspec¬ 
tion within the folds of the buds actively engaged 
in sucking up the juices and preventing the develop¬ 
ment of leaves and blossoms. The exhaustion of the 
juice and sap, and the irritation set up by the larvae, 
soon cause decay, and prevent the fructification of 
the blossom buds. 
Although the Psylla Mallihas been known in Great 
Britain for a long while, it is only somewhat recently 
that it has been recognised as a serious trouble to 
Apple-growers. It seems to have rapidly increased 
in the past four or five years. It is well known in 
many European countries. In Germany it has done 
considerable harm, and the well-known entomolo¬ 
gists, Schmidberger and Taschenberg, have written 
able treatises upon it. It is not known in America, 
but an allied species, known as Psylla pyricola, is 
very destructive in Pear orchards in that country, 
and has been elaborately described by Professor 
Slingerland, of the Cornell University Agricultural 
Experiment Station at Ithaca, in the State of New 
York. 
Life History. 
Many persons have, there is no doubt, noticed 
quantities of little yellowish, or greenish-yellow, fly¬ 
like insects upon the leaves of Apple trees in 
September and October, which upon being 
approached give a leap before using their wings to 
carry them to another leaf. These, in a certain 
degree, resemble some of the "frog-hoppers”— 
species of cercopidse—and, in fact, they have been 
mistaken for them, but upon close examination they 
are very different. 
The winged Psylla, the perfect insect, is seen 
first about the second week in June. Its colour is 
green, for the most part, with slight tinges or shades 
of yellow. The colour, however, is rather variable, 
differing according to the sex and the stages of 
growth. At some periods there are shades of 
yellow, green, red, or brownish-red, noticeable upon 
the body. These are more pronounced at pairing 
time. The female is more brightly coloured than 
the male. The wings are transparent, or slightly 
testaceous, and the legs and antennae are yellow, the 
latter having two and sometimes four dark-coloured 
joints at the ends. The male is about one line (the 
twelfth of an inch) in length ; the female is slightly 
larger. Pairing takes place in September, and the 
eggs are laid in some seasons even up to November. 
In the autumn of the abnormal year 1893 females 
were seen laying eggs as late as November 3rd. In 
this case the eggs were laid upon the youngest 
* Leaflet issued by, and may be obtained free of charge 
from, the Board of Agriculture, 4, Whitehall Place, London, 
S.W. 
shoots, and this appears to be the usual place where 
they are deposited. They may also be put upon 
older shoots and upon branches, but it would be 
difficult to discover them there, on account of the 
deeper furrows, cracks, mossy, and lichenous 
growths. 
As a rule, the eggs are laid singly and embedded 
in the fine hairs upon the epidermis of the shoots. 
Occasionally there are two or three together in a 
row. The eggs are white, or slightly yellow, pointed 
at each end. Taschenberg says they become red, or 
yellowish-red, in the spring, just before the larvae 
come from them. 
The eggs remain until the weather becomes 
spring-like, when tiny flat larvae emerge from them 
and at once get into the nearest buds. When the 
bads expand, the larvae are found within them 
feeding upon their juices. The formation of fruit is 
prevented by their continuous suckings, and the 
blossoms shrivel up and fall off. The buds become 
filled, after a while, with a dirty glutinous fluid, 
termed ” honeydew,” which escapes from the larvae, 
like the fluid secreted by several species of aphides, 
and is mixed with the excretions of the larvae. 
At first the larvae are very small, having flat, 
dirty yellow bodies, with brown or dark spots upon 
them, and but little trace of rudimentary wings, or 
wing cases. Their eyes are red and their feet 
brown. 
The first change, or moult, soon occurs, but there 
is then no very material difference in the larvae. 
After a few days, when the second moult is accom¬ 
plished, the larvae becomes light green, and its rudi¬ 
mentary wings are clearly defined. 
After about another week, with the third moult, 
the rudimentary wings are more developed, and the 
eyes and tips of the antennae become dark. 
From the first appearance of the larva up to 
about a month there are continuous changes in its 
form. At the end of this time what may be termed 
pupation takes place, the larva is quiescent for a few 
hours, the skin is cast off, and the winged psylla 
comes forth. 
When the first moult is over, the larva is seen to be 
covered with fine down, or hairs, apparently to pro¬ 
tect it from wet and injury when the buds have 
expanded. 
The perfect Psylla passes a somewhat long and 
monotonous existence, as it seems, from June until 
pairing time in September. Taschenberg inclines 
to the belief that there may be another generation 
during the summer, and it certainly is strange that 
the insect should pass so many weeks in apparent 
inactivity. Schmidberger, however, who is still the 
chief authority upon the subject, does not hint at a 
second generation. 
Prevention and Remedies. 
It has been found impossible to affect the eggs of 
the Psylla upon the twigs. Like the eggs of many 
other insects, they are protected by hard shells. 
Professor Slingerland tried many washes of turpen¬ 
tine, kerosene, carbolic acid and potash, etc., which 
injured the buds, but did not have the slightest 
effect upon the eggs of Psylla pyri. 
In the case of the early sorts of apples, infested 
trees might be sprayed with disagreeable washes of 
soft soap and quassia, or soft soap and paraffin, 
directly the apples were picked, to prevent the 
psyllae from laying eggs upon the shoots. The 
formulae for these washes would be :— 
I.—6 lbs. of soft soap ; 81 bs. of extract of quassia 
chips ; 100 gallons of water. 
H.—6 lbs. of soft soap ; 4 gallons of paraffin ; 100 
gallons of water. 
In mixing the latter the soap should be boiled in a 
small quantity of water, and the paraffin put into it 
while hot, and then stirred together rapidly, or 
passed through a syringe, or force-pump. This may 
be diluted afterwards in the proper proportion. 
Carbolic acid might be used instead of paraffin, at 
the rate of 3 gallons to 100 gallons of water. 
Some small amount of prevention would ensue 
from pruning trees on which eggs had been laid. On 
young small trees this might be useful, and it would 
probably be advantageous to prune such trees if 
infested more closely than usual. But in the case of 
large orchard trees, it would be impossible to rely 
upon this mode of prevention. 
Spraying when the buds are open, and the larvae 
exposed, would be efficacious to some extent. The 
wash would run down into the bases of the open 
flower-buds and of the expanded leaf-buds, and make 
the quarters of the insects unpleasant, or destroy 
some of them. The quassia wash, as formulated 
above, would act as it does in the case of hop 
aphides, by making the food bitter and unpleasant. 
The paraffin and the carbolic washes would also 
effect this, and kill the larvae probably with which 
they came in contact. Spraying should be done as 
early as possible in the course of the attack, before 
much " honeydew” has been exuded, which would 
hinder the action of the washes. 
PLANTS RECENTLY CERTIFICATED. 
The undermentioned subjects received certificates 
at the meeting of the Royal Horticultural Society on 
the i2th inst.;— 
Nepenthes Amesiae.— The parents of this hybrid 
were N. Hookeriana and N. Rafflesiana, the former 
being the seed parent. N. Amesiae is intermediate 
in character with a much longer pitcher than in N. 
Hookeriana. The pitchers are of great size, and 
heavily blotched with crimson on a pale green 
ground. The wings are very broad, deeply fringed 
and blotched with crimson, but particularly on the 
outer face. First-class Certificate. The exhibitors 
were Messrs. J. Veitch & Sons, Chelsea. 
CosTus iCiNEUs. —The species of Costus, as a 
rule, do not meet with much favour amongst the 
gardening fraternity, nor the public generally ; but 
there are few who do not admire the species under 
notice. The flowers are flat, nearly orbicular, and 
of a warm orange-scarlet. The leaves are elliptic 
and mostly crowded towards the top of the short 
stems that do not much exceed a foot in height. 
There is a cluster of flowers at the top of the stem, 
but they open one at a time, so that the season is 
considerably prolonged. Three dwarf plants were 
exhibited by Sir Trevor Lawrence, Bart, (gardener, 
Mr. W. Bain), Burford Lodge, Dorking, when a 
First-class Certificate was awarded. 
Platycerium aethiopicum.— This noble species 
is also known under the name of P. Stemmaria ; but 
is very little known in gardening circles. The 
barren fronds are about 12 in. to 15 in. long; revo¬ 
lute at the sides so as to cover the object on which it 
is growing, broad, and slightly lobed at the top ; the 
main body of the frond is erect. The fertile fronds 
are altogether larger and bolder than those of the 
well known Stag’s horn (P. alcicorne), 2 ft. to 3 ft. 
long when well grown, and forked in a trichotomous 
manner. The under surface bearing the broad 
patches of sori is downy. A large plant grown on a 
block of Teak was exhibited by Mr. H. B. May, 
Dyson’s Lane Nursery, Upper Edmonton, when a 
First-class Certificate was awarded it. 
Massonia amygdALINA.— In appearance this is 
neither a large nor attractive plant, but the flowers 
have the smell of Almonds many times intensified. 
It is a bulbous plant bearing two roundish, fleshy 
leaves, lying flat on the soil. The flowers are white 
and borne in a dense cluster immediately sur¬ 
mounting the leaves. The stamens project pro¬ 
minently beyond the other parts of the flower. It is 
comparatively new, having only flowered for the 
third time since it was introduced and named. Nor 
does it increase much in size. Botanical Certificate. 
The exhibitor was Sir Trevor Lawrence, Bart. 
-- 
FLOWERING THORNS. 
Whether in flower or fruit the Hawthorns are 
the most showy and hardiest shrubs we have. The 
variety of colours, their certainty of flowering, and 
adaptability for almost any soil makes them very 
valuable. Thorns should always be transplanted be¬ 
fore the early part of March, as they are very 
impatient of disturbance when new roots have 
commenced; the fact of their being early rooting 
subjects should therefore be borne in mind. 
Nor is it only as a flowering shrub that this genus 
is so valuable; our native Hawthorn (Crataegus Oxya- 
cantha) being probably the best all round subject for 
hedges; not growing too strong, thriving in all 
soils, and being easily clipped to any desired size. 
In forming hedges of this, the chief point is to 
secure a good bottom. This is best attained by 
planting them on one side, or else cutting them down 
hard the first season, so as to induce a number of 
breaks from the ground line. Hedges are of little 
use except against the larger animals if a good 
bottom is not secured. What I wish more 
