Garden pests in New Zealand; a popular manual for practical gardeners, farmers and schools

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CAWTHRON INSTITUTE MONOGRAPHS

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EN PESTS

IN

NEW ZEALAND

A Popular Manual

for

Practical Gardeners, Farmers
and Schools

By
DR. D. MILLER

Ph.D., M.Sc,, F.R.S.N.Z., F.R.E.S.

Assistant Director and Chief Entomologist,
Cawthron Institute, Nelson

2/6

EXCHANGE

CAWTHRON INSTITUTE MONOGRAPHS

GARDEN PESTS

in
NEW ZEALAND

A Popular Manual

for

Practical Gardeners, Farmers
and Schools

By
DR. D. MILLER

Ph.D., M.Sc., F.R.S.N.Z., F.R.E.S.

Assistant Director and Chief Entomologist,
Cawthron Institute, Nelson

CONTENTS.

Page

Introduction 5

Chapter* i. : General Review of the Animal Kingdom . . . . 7

Chapter ii. : Soil Organisms and Soil Fertility 12

Chapter iii. : Structure of Insects 17

Chapter iv. : Life Histories of Insects 22

Chapter v. : Sucking Insects 29

Chapter vi. : Sucking Insects (Concluded) 42

Chapter vii. : Leaf-feeding Insects 50

Chapter viii.: Boring and Underground Insects 61

Chapter ix. : Miscellaneous Pests .... . . 67

Chapter x. : Principles of Pest Control 74

Index . 81

Introduction

THIS work deals with the insects and other animals having a
detrimental or beneficial influence upon horticulture in New
Zealand. Its purpose is to supply such general information as will
enable the common animal inhabitants of the garden to be identified
and controlled, to act as a popular guide for the use of practical
gardeners and schools, and at the same time serve as a source from
which the examination requirements set out in the syllabus of the New
Zealand Institute of Horticulture may be met.

As this work is for the benefit of the gardening public, and an
endeavour to diffuse some knowledge of certain natural problems, the
language of the scientist — which, unfortunately, tends to guard what is
known of these problems from the general reader — has been avoided as
much as possible ; at times, however, this ideal cannot be adhered to, but
in such cases the reader should find no difficulty, and should be prepared
to become familiar, with the few terms used. To know the scientific
names of animals without being acquainted with the animals themselves
is a habit to be avoided, and is just about as instructive as memorising
the names of people in a town or telephone directory. But animals
must be named; though their popular names are~ used in the following
pages and as such names are very often misleading, the scientific names
are given in brackets in order to avoid confusion.

In such a work as this, illustrations are of great value, and these
are given wherever possible. One drawback to illustrations is that the
relative proportions of animals may be lost; for example, a microscopic
organism might require magnification by some 4,000 times its natural
size and so become equal to that of some of the most conspicuous insects.
Even with the best illustrations, however, it is essential that the reader
becomes familiar with the animals themselves. This should present no
difficulty to the reader, since he will find in his garden all of the
animals with which he is concerned — mostly insects and their near
relatives. Further, of very; great assistance to him, he will find the
several excellent public museums throughout the country, as well as the
specialists at such research institutions as the Cawthron Institute at
Nelson.

To keep a work for the general reader in a readable form, the desire
of the author to cite the sources from which he derives his information
must be suppressed. If this were not done, the text would rapidly become
littered with endless references, much to the weariness and confusion of
the( reader. Therefore, it should be remembered that a work of this
kind is a compilation from the publications of many scientists, to which
is added what little original information the writer himself might
possess.

Opportunity must be taken here to express one's appreciation of
the assistance given by Mr. W. C. Davies and Mr. L. J. Dumbleton in
the preparation of the photographs and drawings, respectively.

GARDEN PESTS IN NEW ZEALAND

CHAPTER I

General Review of the Animal Kingdom.

AT the outset it is advisable, by reviewing the animal kingdom as a
whole, to secure in perspective the relationships of the animals
with which the horticulturist has to deal.

To most people the animal kingdom is comprised chiefly of those
animals commonly met with in everyday life or in general reading —
the game and domestic animals aiid the fishes, all of which are similar
in that they possess a backbone or vertebral column, and are consequently
known as the vertebrates. Popularly, however, they are generally classed
as the "lower" and "higher" animals; there is certainly some accuracy
in such a haphazard classification, since, though all the vertebrates are,
strictly speaking, the "higher" animals, some are "lower" (e.g., fish,
frog, and bird) than others (e.g., kangaroo, dog, and man, the highest
of all).

But when it comes to the true "lower" animals, that vast assemblage
of less conspicuous creatures, the jelly-fish and corals, worms of all kinds,
sea-urchins, crayfish, wood-lice, spiders and insects, shell-fish and snails,
all characterised by the absence of a vertebral column and known as the
invertebrates, they are not collectively visualised in a general sense as
are the vertebrates. As a rule, these invertebrates are known individually
as independent units, except, perhaps, in the case of worms, insects,
spiders, wood-lice, etc., which are very often collectively and haphazardly
referred to as "insects," a term, in this sense, as ill-defined as it is
unlimited.

That the average person should be more conversant with the verte-
brates than the ' invertebrates is, to a great extent, the natural outcome
of association and training; a possible influence is to be found at the
outset of one's career in the many illustrated nursery books depicting
game and domestic animals, but seldom, if ever, any of the invertebrates ;
and this impression tends to be further fostered in later life by visits
to the zoo, where we meet in person most of the nursery book animals,
and perhaps some of the lower forms, such as insects; but the latter, in
most cases, are there by chance, not design, and against the will of the
authorities.

In recent years., however, more public attention has been given to
the lower animals owing to the detrimental influence of many upon
agricultural development as well as upon public health. That such
animals are capable of ranking as fundamental factors hindering human
progress, may be realised when it is considered that, of the invertebrates,
insects alone comprise nearly four-fifths of the whole animal kindom !
This has been graphically illustrated as follows by F. E. Lutz, of the
American Museum of Natural History: — Extend the arms and fingers
at right angles to the body, and let the distance from the tip of the

GARDE X PESTS IN NEW ZEALAND

middle finger of one hand to that of the other represent the number of
different kinds of living animals: then the last joint of the middle
finger of the right hand will be proportionate to the number of mammal?
(kangaroos, hoofed animals., rabbits, man, etc.), the second joint to the
reptiles and their relations, the first joint to the birds, and the distance
.be^yec'Q the -'kmickjes ;ar.d the wrist to the fishes. "In other words, you
''c'ah' hold ' the so-called Zoological gardens and their aquarium annexes
in one hand." Finally, the distance between the wrist of the right arm
and the tip of the middle finger of the left will proportionately represent
all the known species of invertebrates, and of this section of the extended
arms all except between a wrist and an elbow will be insects.

The zoologist classifies the animals under twelve main divisions,
of which eleven contain the invertebrates and one the vertebrates; these
divisions are arranged in a series, the first containing the simplest or
lower animals, and the last the most complex or highest. A glance at
this classification will serve to give some idea of the relative position
in the animal kingdom of the animals which will be dealt with in the
following pages. The very lowest forms, belonging to the first division,
are micro-organisms known as the Protozoa ; they inhabit water and soil,
and live upon their own kind or upon minute plants, including bacteria,
or are parasitic upon the higher animals, some of these parasites causing
such diseases as malaria. The Protozoa are single units of living matter
(protoplasm), and may be referred to as the one-celled animals; they
are mostly microscopic, and lead an independent life, or are associated
in colonies, but are capable, as a rule, of carrying on independently all
the functions of life, though there are no organs such as those of diges-
tion, respiration, and circulation, as we know them in the higher
animals. It is amongst such simple forms that the distinction between
the lowest animals and plants ceases to be clear. As will be discussed
later, there is evidence that certain Protozoa have an important influence
on soil fertility.

The remaining eleven divisions contain all other animals, ranging
in size from mere specks to the mass of the elephant; the bodies of these
are built up of a complex aggregate of countless cells of protoplasm
arranged in groups to form the organs of digestion, circulation, respira-
tion, reproduction, etc., each having its definite function in the animals'
lives. The following ara some typical or well-known examples of each
of these division?, the technical names, with the exception of the
Protozoa, not being given: —

The Protozoa (reference should be made here to Fig. 1) are fol-
lowed by (2) sponges; (3) jelly-fish, sea-anemones, corals; (4) flat-
worms (tape- worms, etc.) ; (5) round worms (thread-worms, eel-worms) :
((>) sea-mats, lamp-shells; (7) wheel-animalcules; (8) star-fish, sea-
urchins: (9) segmented worms (earthworms); (10) crayfish, woodlice.
centipedes, millipedes,, spiders, mites, insects; (11) shell-fish, slug?,
snails; (12) fish, frogs, lizards, birds, hedgehogs, rabbits, man.

So far we have reviewed the animal kingdom from one aspect only
—that of classification, based on the resemblances and differences of the
individuals. It is now necessary to look at the subject from the view-
point of the horticulturist — that is, the relationships of the animals to
their surroundings, or environment, and to the welfare of man. Of the

GARDEN PESTS IX NEW ZEALAND

two great life-groups — animals and plants — the plants are of funda-
mental importance; without them no animal could exist, since, of all
living things, it is the green plants alone that are able to convert the
inorganic chemical constituents in soil, air and water into living matter
or protoplasm; and all animals, either directly or indirectly, are
dependent upon plants for their food supply. Plants, therefore, may be
looked upon as the primary producers of life, and animals as the
consumers. It is in this respect that the horticulturist becomes
interested, in that certain of these consumers destroy too many of the
plants grown by him for other purposes; fortunately, not all of the
consumers are destructive; many are of very great use to the horticul-
turist and mankind in general.

The last point is well illustrated by the following classification of
the animal kingdom based upon, the part it plays in human welfare;
this is a modification of the scheme adopted by the British Museum of
Natural History: —

Group I. — Wild or domesticated animals used by man as beasts of
burden, source of food, or in the manufacture of various products — e.g..,
sponges, crayfish, bees, silk-worms, shell-fish, and various vertebrates.,
as fish, birds and mammals.

Group II. — Animals detrimental to man's welfare, attacking man
himself; animals and plants of value to him, or the products derived
therefrom — e.g.., Protozoa, parasitic worms, mites, insects, and such
vertebrates as certain birds and mammals.

Group III. — Animals aiding man's welfare, as scavengers, or by
pollinating flowers, or by attacking and checkingpmieh animals as are
included in Group II. — e.g., Protozoa, parasitic worms, earthworms,
parasitic insects, spiders, and such vertebrates as certain birds and
mammals.

An analysis of the above classification shows that animals both aid
and hinder the progress of man, hence the use of the terms "beneficiaP
and "destructive." In nature, however, these terms are not altogether
applicable in the same sense, since the balance maintained between
animals and plants under natural conditions is an extremely fluctuating
one, though sufficient for natural purposes; with man, however, the case
is different. In order to compete in the world's markets, and to supply
the growing demands of increasing population, a much higher and
dependable standard of productivity is required than is found in nature.
Consequently, whilst utilising, and increasing the efficiency of the so-
called natural enemies as auxiliaries in his fight against destructive
animals, man has found it necessary to develop an effective system of
artificial control, involving chemicals, resistant plants, cultivation, crop
rotation, etc., for the purpose of maintaining a more stringent balance
to meet his requirements.

Historical Review of New Zealand Conditions.

The animal population of European New Zealand is very different
from that of pre-European times, a position brought about naturally
enough by the changes resulting from agricultural development as
practised in the Old World, and the consequent creation of an environ-
ment foreign to the country.

GARDEN PESTS IN NEW ZEALAND

Though the official date of the settlement of Xew Zealand by
Europeans is* 1840, the influences, inaugurating that upheaval of the
natural conditions which was later to have such a marked effect on the

Fig. 1. — Some common animals grouped to represent the twelve main divisions
•of the auimal kingdom.

10

GARDEN PESTS IN NEW Z E A LAND

economic development of the country, had commenced many years
earlier.

When the first Europeans set foot in New Zealand, they must have
been impressed by their unique surroundings, totally different from
anything to be met with in the Old World. They found the country
dominated by a forest quite unlike the forests of any other land, and
inhabited by an animal population presenting many unusual features.
This terrestrial population was characterised by an abundance of insects
and spiders, and a paucity of vertebrates excepting the birds ; the verte-
brates consisted of a species or two of frogs, a .few species of lizards,
some 200 species of birds, and two species of bats, the last being1 the
only terrestrial mammals. In fact, the insects, spiders and birds were
the dominant animals, a feature common to other parts of the world,
but the scanty vertebrate population, other than birds, was a character-
istic of primeval New Zealand.

New Zealand being a country fitted for agriculture, settlement by
Europeans naturally resulted in extensive and rapid changes, since the
settlers brought with them the knowledge, implements, animals and
plants of the civilised world; and to make way for settlement, it was
necessary to remove the forests and drain the swamps, and to replace
them with cultivated crops and pastures. These activities have been so
thorough, that, within a period of some 90 years practically the whole
of the original North Island forests, and the greater pai't of those of
the South Island, have been cleared.

An outstanding feature of these changes is-that many of the pests
associated with the agricultural animals and plants have been brought
to New Zealand with the animals and plants they infest, and these
exotic pests comprise by far the greater proportion of the destructive
animal population, there being but few native species forming the
balance. For example, 71 per cent, of the destructive insects are exotic,
and 29 per cent, native, while all the parasitic worms of economic import-
ance, all the destructive birds (e.g., sparrows) and mammals (e.g., deer,
wild pigs, and goats) are introduced.

The exotic factors that have set up this new environment may be
summarised as follows: —

(1) Clearing of the native vegetation."

(2) Introduced plants: e.g., grasses, forage crops, trees, etc.

(3) Introduced game animals: e.g., deer, pigs, rabbits, birds, etc.

(4) Introduced destructive animals, infesting animals and plants
of economic value : e.g., parasitic worms, insects, etc.

(5) Animals imported to control pests, but which have become
destructive themselves: e.g., weasels, birds.

11

GARDEN PESTS IN NEW ZEALAND

CHAPTER II.

Soil Organisms and Soil Fertility.

IX the first chapter the plants were referred to as the primary
producers of life, and the animals as the consumers; the former not
only furnish nourishment for their own growth., but also for the support
of the animal world as a whole. Living plants (in reference to green
plants) utilise the sun's energy in the manufacture of their complex
food materials from comparatively simple chemical compounds. These
latter compounds are carbon dioxide, derived from the air through the
agency of leaves, and a weak solution of various chemical compounds in
water, derived by means of the roots from the soil, and carried up
through the plant to the leaves, where the elaboration into the complex
compounds to be utilised by the plants as food takes place.

These comparative!}7 simple compounds from which the plants
elaborate their nourishment are the raw food materials, and that they
must always be available -for plant growth, is evident when one considers
the vast areas of vegetation that cover, with the exception of desert
regions, the surface of the earth. Under moist climatic conditions it
has been calculated that some 500 tons of carbon dioxide and 1,000,000
tons of water, having the raw food materials in solution, are used
annually by one square mile of dense forest. For their development,
therefore, plants require : —

(1) Sunlight as the source of energy for the carrying on of their
life functions;

(2) Air for the supply of carbon dioxide, oxygen, and, indirectly,
nitrogen ;

(3) An ample supply of water required for the living tissues and
as a vehicle for the transport from the soil of

(4) The raw food materials, in the form of various chemical
compounds.

\Yith the exception of the carbon dioxide derived from the air, all
the raw food materials — water, nitrates, phosphates, sulphates, potas-
sium, calcium, magnesium, iron, etc. — are present in the soil, though
only a part of them is in a form suitable for imbibition by plants. In
the formation of these food materials, which render the soil fertile,
physical forces and the activities of living organisms play a leading
part. Our immediate concern is with the influence of these organisms
upon soil fertility, but it is advisable to give some consideration to the
soil itself, since it is the environment in which the organisms live, and
with which their existence is intimately associated; in this respect
attention will be confined to the type of soil usually cultivated by the
horticulturist, and to the uppermost layers — that is, approximately,
within one- foot of the surface.

12

GARDEN PESTS IN NEW ZEALAND

Soil is the product of disintegrated and weathered rocks with which
are mixed the residues of organic matter. Apart from the particles of
disintegrated rocks, which form the matrix, soil contains chemical com-
pounds of two kinds: those of a purely mineral nature derived from
the inorganic components of the original rocks, and those of an organic
origin derived either from the ancient remains of organisms, which, in
the case of sedementary deposits, became incorporated in the rocks at
the time of their origin, or from the remains of present-day plants and
animals decomposed by soil organisms. In addition, there is the humus,
which has a fundamental physical influence, and for the production of
which soil organisms are responsible.

In the initial stages of soil formation during the disintegration
and decomposition of rocks, the first type of soil to be formed is suitable
for the growth 'of only certain plants ; it is of a purely mineral nature,
containing raw food materials derived mainly from the rocks and not
from organic matter, unless from such organic residues as were incor-
porated in the rocks during their formation in ancient times. Such
soil cannot sustain the higher types of green plants, no*r is it populated
by soil organisms; it furnishes suitable pabulum, however, for the
nourishment and growth of the more lowly types of vegetation, which
are able to convert to their benefit the limited supply of food materials
available. The complex organic compounds that such primitive plants
elaborate from these food materials of purely mineral origin, and
incorporate in their tissues, are, after death, returned to the soil, which
becomes correspondingly enriched, and a favourable environment for

Figure 2

THE THREE MAIN TYPES OF SOIL PROTOZOA.
Magnified 300-400.

13

GARDEN PESTS IN NEW ZEALAND

the establishment of organisms; the latter reduce these plant residues
to humus, and during this process of decomposition produce food
materials of an organic origin suitable for the nutrition of the sequential
plant covering. So the process proceeds until a soil is formed of
sufficient extent and quality for the support of a more extensive and
increasingly complex vegetation; thus, in the cycle of life and decay,
stores of organic compounds are elaborated by plants and returned to
the soil, which they enrich, and where they are decomposed by
organisms, and so maintain the supplies of food materials suitable for
the maintenance of vegetation.

These phenomena of plant establishment and succession, correlated
with soil formation, were clearly demonstrated by the re-establishment
of vegetation after the soil and plant life had been) destroyed by the
historic eruption in 1883 of Krakatoa, a volcanic island in the Straits
of Sunda, between Java and Sumatra. The first plants to be established
on the volcanic deposits were species of terrestrial alga?, which gradually
spread and built up soil suitable for the development of soil organisms
and for the growth of seeds brought to the island by birds and ocean
currents. So rapid were the changes brought about by these influences,
that within a period of twenty years after the eruption the barren
ground was reclothed by a dense and varied plant covering.

Organisms that form part of the organic complex of the soil range
from the more conspicuous species, such as slugs and snails, insects,
spiders, wood lice, millepedes, earthworms and eelworms, to such micro-
scopic forms as protozoa, fungi, algae and bacteria, the last three being
members of the plant kingdom. These organisms may be grouped as
follows : —

( 1 ) Temporary inhabitants that .enter the soil for shelter, or to
feed as scavengers on decaying organic matter, or both — e.g.,
slugs, snails, wood lice, certain insects and some eelworms.

(2) Permanent inhabitants that are dependent on the soil for their
development and supplies of food, either throughout or during
most of their lives — e.g.., certain insects and spiders, millepedes,
earthworms, eelworms, protozoa, fungi, algae and bacteria.

The organisms in the first group play a comparatively minor part
in soil development, and influence its fertility to an almost negligible
extent, the temporary scavengers, perhaps, being of more importance
since they aid in the reduction of vegetable residues. The forms in the
second group, however, are invaluable as soil-making agents and in the
production of plant food materials, the least important among them
being the insects, spiders and millepedes. Many are merely scavengers,
but some insects, such as grass-grubs and the caterpillars of certain
moths, and millepedes, feed upon living plants and so add organic
matter to the soil in their excreta, which also contains quantities of soil
swallowed with the food, this latter mechanical action aiding in the
pulverising and opening up of the soil; certain eelworms, too, that
attack living plants play a somewhat similar part, .in that they are
primary causative agents in the decay of healthy tissues. Other forms
of insects, together with spiders and some eelworms, are predaceous
upon their fellows, the remains of the latter being added to the soil

14

G A 11 D E X P E S T S I X X E \V Z E A L A X D

residual complex. Apart from the activities of all these organisms,
however, it is the earthworms, protozoa, fungi, algae and bacteria that
have the most fundamental influence upon soil fertility.

Earthworms may be Correctly called the great soil builders; they
burrow through it, allowing the free passage of ah? and water; they
swallow large quantities, which they eject on the surface in the form
of "worm-casts," the soil materials being well mixed in the process;
they pull underground leaves and other parts of plants from the surface
and so increase the supply of organic matter for the action of the micro-
organisms that bring about decomposition. Further, by depositing their
"casts" on the surface, earthworms soon cover the accumulations of dead
vegetable matter, as has been illustrated by Darwin in his classic work
on these animals. Without the aid of earthworms — e.g., in sour soils in
which they do not abound — the plant residues accumulate on the
surface, to form a partially decomposed, peaty mass, which only a
limited number of plants can tolerate.

The protozoa, fungi, algae and bacteria are . all microscopic
organisms, and are the agents responsible for the decomposition of the
organic residues in the soil; they do not act as independent units, the
processes of one group being dependent upon and intimately related
with those of the others. During the activities of these organisms
various organic and mineral substances are decomposed or transformed
into materials, such as humus and the inorganic compounds of nitrogen,
phosphorus, potassium, etc., necessary or helpful for the growth of
plants.

The protozoa (see Chapter I.) are the lowest and simplest forms
of animal life, being mere specks of living matter. Three different
groups of soil protozoa occur (Fig. 2). Some, like the amoeba, progress
by streaming movements,, extruding temporary extensions of their sub-
stance in the form of finger or thread-like processes; the bodies of
such protozoa may be naked, or enclosed in a shell-like covering secreted
by the organism itself, or protected by an accumulation of particles
of foreign matter. Some have a body of more definite shape and
progress by means of the whip-like action of one or two thread-like
processes, or flagella, arising from one end of the body. Such forms
are the most numerous in the soil. Others, also of definite shape, control
their movements by means of short, hair-like processes, OT cilia, either
distributed over the body or restricted to definite regions.

The protozoa are widely distributed, being most abundant in the
richer types of soil, especially during the spring and autumn. A great
amount of research has been undertaken at Eothamsted, England, and
elsewhere, on the part played by protozoa in soil fertility ; the evidence
thus secured points to the probability that some of these organisms may
be detrimental in that they devour certain kinds of bacteria responsible
for the production of nitrates and other substances of nutritive value
to plants. The extent of this may be realised from the fact that in a
definite weight of soil (about l-28th of an ounce) the micro-population
was calculated to include not only about 1,550,000 protozoa, of which
430,000 were amoebae (Fig. 2), but also some 6,000,000,000 bacteria.
Observations showed that a single bacteria-destroying amoeba required
about 400 organisms for its nourishment, so that the amoebae, to say

15

GARDEN PESTS IN NEW ZEALAND

nothing of the other protozoa, present in the weight of soil above-
mentioned,, would be capable of destroying about 172,000,000 of the
bacterial population. Since the partial sterilisation of soil by steam
results in an increase of fertility, it is thought, on account of the
sterilisation destroying the protozoa, being more susceptible, and not the
bacteria, that protozoa inhibit the activities of the bacteria to such an
extent as to reduce the fertility of the soil; but this is a subject as yet
open to argument. Apart from the bacteria-destroying protozoa, there
are other forms that are thought to have something to do with the
decomposition of organic substances.

The fungi, alga? and bacteria are amongst the lowest forms of
plant life, and hold somewhat the same position in the plant kingdom
as the protozoa do among animals; they are, especially the fungi and
bacteria, of primary importance in the maintenance of soil fertility.
The role of alg;ae lies mainly in increasing the organic content of the
soil, and they are invaluable in developing favourable conditions for
the establishment of vegetation on purely mineral soils. The fungi and
bacteria are responsible for setting up the intricate reactions involved
in the decomposition of organic matter, the bacteria being concerned
in practically all of the chemical processes going on in the soil. Both
fungi and bacteria are of two kinds : those that bring about decomposi-
tion, and those that live in a reciprocal relationship with plants upon
the roots of the latter. Such relationship, which benefits both organisms
and plants, is called symbiosis, the fungi being known as mycorrhiza,
while the bacteria, form nodules on the roots of such plants as the
legumes.

16

GARDEN PESTS IN, NEW ZEALAND

CHAPTER III.

Structure of Insects,

ALTHOUGH insects present a great variety of forms, they never-
theless agree in general features; thus by studying the structure
of some generalised species, which will give a broad idea of the main
characteristics, one is enabled to recognise different structural modifica-
tions assumed by various species. For this purpose a weta, grasshopper,
or cockroach may be taken as a type.

Just as in the case of the crayfish, so the body of an inisect is
completely covered and protected by a continuous "shell/' very solid
in some insects, more or less pliable in others, but even in the most
delicate forms tending to become rigid and brittle after death. This
shell acts as a skeleton and as a very effective armour-plating, protecting
and supporting the soft body within. Unlike the shell of the crayfish,
which is mainly calcareous, that of insects consists of a horny substance
called cliitin, secreted by the underlying skin, and constitutes what is
known as a cuticle. It is due to this horny cuticle or shell that the
form and colour of most insects are preserved after death, though the
enclosed body tissues decay unless preserved in some suitable medium.

The cuticle, though forming a complete covering, does not enclose
the body in an inflexible shell ; flexibility is allowed by the cuticle being
formed of a segmented series of strongiy-chitinised sections alternating
with skin-like, feebly-chitinised, and very elastic sections; this arrange-
ment gives freedom of movement to the enclosed body, as is readily seen
in the movements of a caterpillar.

There are three distinctly separated divisions of the insect body —
head, thorax, and abdomen — each consisting of a varying number of
segments (Fig. 3). The head segments are so closely fused as to be
practically untraceable, the cuticle forming a rigid capsule; the thorax,
to which the head is attached, carries the wings (when present) and
the legs, and consists of three segments; posterior to the thorax is the
abdomen, comprised of several segments, which show the typical
segmentation of insects better than any other part of the body.

The head capsule is more or less freely movable on the thorax, and
bears certain sensory organs, together with the mouth appendages. The
sensory organs are the eyes and the feelers, or antennae. On each side
is a compound eye of varying size, according to1 the insect; each eye
consists of a variable number (from a comparative few to several
thousand) of microscopic, hexagonal lenses, each of which records a
separate image; Between the compound eyes, on top of the head, are
three simple eyes in some insects, but in others one or all of these may
be absent. Between the compound eyes on the front aspect of the head
is a pair of feelers, or antennae; they consist of a variable number of

17

O A K D E X P E S T S I X X E W Z E A L A X D

joints, are freely movable and highly sensory, thread-like or hair-like,
short, or longer even than the whole body, and may be bare or clothed
to a varying degree with hair or bristles. On the antennae are the
organs of touch, smell, and sometimes hearing.

-/ir-Hind Thorax

\Wmg6-leg

_ 'Jfea d Cgpsu ?e _
Compoun

Nerve Centers.', _

GARDEN PESTS IN NEW ZEALAND

When the head of a weta, grasshopper, or cockroach is removed
from the body and boiled for a few minutes in a 10 per cent, solution
of caustic potash, and then washed in water in order to remove the
muscles and other tissues, a large opening will be seen on the posterior
surface where the head was attached to the thorax; also, if the mouth
appendages are pulled apart, they will be seen to surround another
opening on the lower aspect of the head capsule, marking the position
of the mouth. The digestive canal passes from the mouth through the
posterior opening into the thorax.

The mouth appendages are as follows (Fig. 3) : — Suspended from
the fore aspect of the mouth opening is a more or less conspicuous
movable flap, which forms the upper lip, while from the posterior
aspect of the same opening is another suspended appendage forming
the lower lip; this latter appendage is really] a complicated one, and
bears a pair of short, jointed appendages— the palps — which are sensory
organs, while on its inner surface — i.o., within the mouth — is a swollen
area or tongue, an organ very greatly "modified in certain insects.
Between the upper and lower lips, and suspended from both sides of
the mouth opening, is a pair of true jaws immediately behind the upper
lip, followed by a pair of accessory jaws immediately before the lower
lip; these jaws do not move up and down, but have a side-wise action,
closing and opening like scissor blades. While the true jaws are each
of one piece, the accessory jaws consist of several parts, and each bears
in addition a jointed palp, as in the case of the lower lip. The upper
and lower lips serve to hold the food in the mouth, the true jaws
nibble or tear oh* portions of the food and masticate it -(if -the term
can be used), while the accessory jaws, aided by the lower lip1, manipu-
late the food during the process of feeding.

The comparatively simple arrangement of mouth parts found in
the weta, grasshopper, and cockroach, as described above, is characteristic
of all insects that gnaw or chew their food — e.g., earwigs, beetles and
their larvae or grubs, the caterpillars of moths, and! so on. There is,
however, a vast number of insects that has developed more or less
complex variations of this generalised pattern, according to the manner
of feeding.

Hie mouth parts of the worker honey-bee, for example, have the
jaws adapted for eating pollen and moulding wax for the comb ; the
accessory jaws, however, are lengthened, though their palps are reduced
to mere vestiges in contrast with the elongated palps of the lower lip ;
the most remarkable modification is that of the greatly elongated
tongue, with its spoon-like tip adapted for reaching nectar of flowers
having deep-seated nectaries. For the same purpose, the mouth parts
are modified in a moth (Fig. 3) to form a long proboscis, which lies
curled up in a spiral beneath the head when not in use; in this case
the proboscis is the modified accessory jaws, the remaining mouth parts,
with the exception of the well-developed palps of the lower lip, being
greatly reduced. In a blood-sucking insect, such as* the female mosquito,
all the mouth parts are well developed, but are very delicate and greatly
lengthened and suited for piercing the skin. The greatest modification
is found in the blow-fly proboscis, which is a soft, sucking tube, with no
outward resemblance to the generalised plan, except for the palps of
the accessory jaws. The mouth parts of insects (e.g., aphids) which

19

GARDEN PESTS IN NEW ZEALAND

feed on the nutrient sap of plants, just in the same way as mosquitoes
do on blood, are modified for puncturing the tissues of plants; in such
insects the upper1 lip is short, and both pairs of palps are atrophied,
but the jaws and accessory jaws are greatly lengthened in the form of
bristle-like stylets, which lie in a groove along the equally lengthened
lower lip (Fig. 3). The manner in which insects feed is orf great
importance in controlling them with insecticides, and the two types to
bear in mind are those that chew their food and those that suck the
feap of plants, reached by puncturing the tissues.

As already stated, the thorax consists of the three segments imme-
diately behind the head, and carries the organs of locomotion ; its three
segments are distinct, and may be referred to, respectively, as the fore,
middle, and hind thorax. The cuticle of each thoracic segment consists
of a number of chitinised plates connected by membranous areas; these
plates are arranged in three series — the baclq or dorsal; the lower or
ventral, forming the sternum; and the lateral, or side-pieces, connecting
the dorsal and ventral ones.

At the lower surface of each thoracic segment is attached a pair
of legs, the members of each pair being separated by the sternum of
the segment to which they belong. The presence of three pairs of legs
is a character by which insects can be distinguished from all other
animals; indeed, on account of this feature, insects are sometimes called
the hexapods, or six-legged animals. Each leg is covered by a continua-
tion of the bod}r cuticle, and is five-jointed; the first two joints at the
attachment to the body are small ; the next two are long, and form the
greater part of the limb; while the fifth, or foot, consists of a varying
number of small joints, the terminal one bearing a pair of claws.

In the typical winged insects there are two pairs of wings: one
pair attached to the middle thorax, and the other to the hind thorax;
owing to the development of muscles controlling flight, the middle and
hind thorax of winged insects are usually better developed than the fore
thorax; this is especially noticeable in the thorax of two- winged flies
(daddy-long-legs and blow-flies), where the hind wings are reduced to
vestiges, the power of flight being thus confined to the middle thorax,
which forms by far the greater portion of the whole thorax.

Each wing, arising from the junction of the dorsal and lateral
thoracic plates, is a bag-like extension of the cuticle, flattened leaf-like,
so as to form a double flexible membrane. The wing membrane is
supported by several ribs or veins, which may be very numerous (grass-
hopper) or few (aphid), while the fore edge, where it cuts the air in
flight, is bordered by a stouter vein, ensuring rigidity. The fore and
hind wings of some insects work independently, but in agreement of
movement, while in others the fore and hind wings of each side are
coupled along their adjoining margins, giving greater rigidity during
flight.

The abdomen of insects consists of a varying number of visible
segments ; each segment is covered by an upper and lower chitinous
plate connected by membrane, there being no side plates as are found
in the thorax. There are no organs) of locomotion (except in a very

20

GARDEN PESTS IN NEW ZEALAND

few cases), the only appendages being those connected with reproduc-
tion; the latter are well developed in the female weta, where the egg-
laying apparatus, or ovipositor, projects blade-like from the apex of
the abdomen. In very many insects, however, the external -reproductive
organs are not readily seen without special study.

All insects, from the largest to the most minute, contain internally
a well-formed heart and a digestive, reproductive, respiratory, and
nervous system (Fig. 3), while the spaces surrounding these organs are,
for the most part, packed with a complex system of muscles. The
heart is a delicate tube lying along the middle of the back or dorsal
surface of the body, immediately under the skin, and extends almost
from one end of the insect to the other; in an almost similar position,
close to the lower or ventral surface of the body, the nervous system is
situated, and consists of a chain of nerve centres, or ganglia, connected
by a double nerve cord, the most anterior of these ganglia being in the
head and forming the brain, the following three lying in thei thorax,
one to each segment, while the remainder are confined to the abdomen,
one ganglion to each segment, as in the thorax. In many insects the
number of nerve centres is reduced, owing to the fusion of two or more.
The reproductive organs are located in the abdomen.

The digestive system consists of a tube (Fig. 3), with its append-
ages, opening at the mouth and at the posterior end of the body; this
alimentary canal may be straight and simple, or convoluted and complex,
according to the insect and the nature of its food. Respiration in
insects is carried on by means of a system of air tubes (Fig. 3), which
branch and re-braneh to form an intricate system of delicate tubular
airways, carrying the atmosphere to all tissues of the body ; the main air
tubes open at the surface by a series of breathing pores normally
arranged along each side of the body, except on the head; these pores
are best seen on a caterpillar or o i the abdomen of adult insects.

GARDEN PESTS IN NEW ZEALAND

CHAPTER IV.

Life Histories of Insects.

NO doubt owing to the endless assortment of sizes, from mere specks
to'giants of a few inches, a widespread idea has arisen, particularly
in regard to such insects as have a general resemblance to one another,
that the smaller individuals are the younger stages of the larger.
Though gradation in size may be a sign of successive ages in certain
insects, the presence of functioning wings denotes that growth has
ceased; in the case of wingless insects, the characters of maturity may
be less conspicuous. Although there may be at times a fairly wide
range in size among fully-grown individuals of the onef species, such
variation is not due to age, but to certain factors influencing the insect
during growth, such as the abundance or scarcity of food supply, and
favourable or unfavourable climatic conditions. On the other hand, the
sex to which an individual belongs is often responsible for difference in
size, males very frequently being smaller than females. Size, therefore,
is by no means a sign of age, and the smaller winged insects must not
be regarded as the young of the larger ones, no matter how close is the
resemblance.

Insects, with the exception of certain species giving birth to living
young, are reproduced from eggs laid by the females; with few excep-
tions, the latter take no further interest in, the eggs beyond placing
them in surroundings offering the most favourable conditions for their
well-being, and a sufficient food supply for the forthcoming young ; each
egg is protected by a delicate shell, through which the young insect
makes its way on hatching.

On emerging from the egg, the young insect commences to feed
and grow in size, until very soon a stage! is reached when the cuticle
or shell becomes too small for the enclosed insect; a fluid then collects
between the cuticle and the underlying skin, and a new and more
roomv cuticle is secreted by the latter; on this process being completed,
the old chitinous covering splits, and the insect withdraws itself. This
moulting takes place several times, until the body is fully grown, when
the cuticle formed at the last moult is retained by the now adult insect
for the rest of its life.

The different stages through which an insect passes from egg to
adult constitute its life history, or life cycle, and the relation of the
latter to the seasons, its seasonal history. According to the species, a
full twelve months or even more may be necessary for the complete life
cycle, or the cycle may be repeated several times within the year; when
the cycle occupies twelve months, the insect is single-brooded; but two,
three, or four-brooded, etc., when the cycle is repeated two, three, or

GARDEN PESTS IN NEW ZEALAND

four times, respectively, in the year. Climatic and food-supply condi-
tions have a distinct influence on the number of broods, the one species
in many cases being single-brooded in colder, and two or three-brooded
in warmer climates. During the winter, when the temperature is low
enough, insects are more or less dormant in some stage of their life
cycle ; such a state is the period of hibernation.

6

4

FIGURE 4.

1, Silverfish. 2, Earwig; a, young larva; b-d, later stages; e, adult. 3, Cicada; f, young
larva; g, resting stage prior to emergence of adult; h, adult. 4, Thrips ; 1 and j, larvae;
k, first stage pupa; 1, second stage pupa; m, adult. 5, Aphis-lion ;. n, larva; o, pupa; p,
adult. 6, Moth; q, egg; r-t, larvae; u, pupa; v, adult. 7, House-fly; w, egg; x-z, larvae;
aa, puparium ; bb, adult. NOTE : Developing wings shown in black.

GARDEN PESTS IN NEW ZEALAND

All insects do not follow the same method of development from
egg to adult, and the adaptations of structure and habit are many and
varied as well as simple and complex. Species having a complex
development, during which they pass through stages, each differing in
form from its predecessor,, undergo what is known as a metamorphosis;
contrasted with such insects are those developing in a simple manner
without pronounced differences in the form of successive stages, the
ycung resembling the adult in most features except size and maturity —
these insects are without a metamorphosis. Intermediate between these
two extremes are other insects with a partial metamorphosis.

A consideration of the life cycle of some common insects will serve
to illustrate the principles of development discussed above. Firstly,
will be taken examples of complex development or complete metamor-
phosis; secondly, examples of simple development or absence of
metamorphosis, followed by a review' of species having a partial
metamorphosis, thus linking the first two types.

A convenient type of insect undergoing a complete metamorphosis
is any common moth (Fig. 4) ; one of the most suitable, most easily
obtained in all stages and commonest in any part of the country from
spring to autumn, is the magpie moth (Nyctemera amnulata) and its
caterpillar, the "woolly bear/"' The moth, unlike most oikits kind, is a
day-flying species, and is very conspicuous owing to its black colour
relieved by white wing spots, and orange-yellow bands on the abdomen ;
the equally conspicuous caterpillar, feeding on groundsel, ragwort and
cineraria, is black, with a very hairy body marked with narrow brick-
led lines.

The eggs are laid in clusters by the female moth on the under side
of the leaves of the caterpillars' food-plant; at first the eggs are of a
pale green colour, but assume a darker yellowish tint within a few
hours, and finally a leaden colour some time later. These colour
changes are due to the developing embryo, and just before the young
insect (the caterpillar in this case) hatches, its outline as it lies curled
within the egg is easily seen through the transparent egg-shell; near
the top of the egg is a black spot marking the position of the cater-
pillar's head, while the numerous delicate black lines below the egg
surface are the black hairs with which the caterpillar is clothed. Accord-
ing to temperature and humidity, the incubation period — that is, the
period between egg-laying and the hatching of the young caterpillar —
varies from eight days to three weeks. The process of hatching occupies
about two1 hours, the young insect using its jaws to eat an exit hole
through the egg. The caterpillar stage— indeed, the first stage of all
insects — is known as the larva.

At first the larva of the magpie moth, measuring about one-
sixteenth of an inch long, is pale yellow in colour, except for the black
head and hairs clothing the body ; very soon, however, the body becomes
characteristically black, and develops the reddish lines. During growth
the larva feeds continuously day and night, undergoing from five to ten
moults before becoming fully grown. During a moult the cuticle of the
head is cast separately from that of the body.

The body of the larva is worm-like, not only in general form, but
also in its segmented appearance ; it is, however, a very different animal

24

GARDEN PESTS IN NEW ZEALAND

from a worm. The larva has a distinct head, a pair of eyes, and short
antenna^ and a set of mouth parts, similar to those of the weta; or
grasshopper, well adapted for devouring foliage; the first three segments
behind the head correspond to the thorax of the moth, and each bears
a pair of short feet; the remaining segments are those of the abdomen,
andi 'have no true feet, but six pairs of sucker-like appendages called
pro-legs. The number of pro4egs varies from four to six pairs, accord-
ing to the species of moth, and are found only on the larva.

The time occupied by larval development of the magpie moth
varies from forty to eighty days in summer and autumn ; but if winter
intervenes, causing the larvae to hibernate before completing their
development, the larval period may be as long as two hundred and forty-
eight days; normally this insect hibernates in the larval state, com-
pleting its development during the following spring. Throughout
winter the larvae hibernate singly or in colonies under loose bark, in leaf
axils, or any suitable crevice.

The fully-grown larva measures about one and a-half inches long.
Prior to the final moult it ceases to feed, and wanders in search of a
suitable place in which to undergo the next transformation, usually
among stones, rubbish, or under loose bark, etc. There it spins a white
silken cocoon, among the strands of which are entangled the long black
body hairs; herein the larva undergoes the final moult, the cast cuticle
being easily seen at one end inside the cocoon.

The insect, however, has now assumed a form quite diiferent from
that of the larva; this form is the chrysalis of^pupa, and as such is
incapable of locomotion and feeding. The pupa measures about three-
quarters of an inch long, is yellowish at first, but soon becomes black
with yellow markings, while the form of the future moth (head,
antennae, thorax, legs, wings and abdomen) can be traced oil the pupal
cuticle. After from about two to five weeks, the pupa opens by a cross-
shaped slit on the back just behind the head., and the moth draws itself
out. At first the moth is comparatively helpless after having been
confined within the limited space of the pupal cuticle ; soon, however,
the body hardens, the wingtj smooth out, and the insect is ready for
flight.

Metamorphosis is carried to a much higher state of perfection in
the case of such insects as blowflies and houseflies (Fig. 4). The larva,
or maggot, is without any external sign of head and legs, though these,
together with the wings of the future fly, develop from rudiments
within the body of the maggot. At the final moult the larval cuticle
is not discarded, as in the case of the moth, 'but hardens to form a case
—the puparium — witnin which the pupa lies.

The life-cycle of the magpie moth is illustrative of the . principles
of metamorphosis characterising the development of a great many
insects, such as all moths and butterflies, beetles, flies, bees and wasps,
etc.; but, although the general characters of the larva, pupa, and adult
moth are common, with but slight variation, to corresponding stages
of moths and butterflies as a whole, these stages in other insects, though
readily recognised, have their own characteristics.

25

GARDEN PESTS IN NEW ZEALAND

Outstanding features in a life-cycle involving metamorphosis are
that growth takes place onlM in the larval state, and that the insect
parades through life in different guises — egg, larva, pupa, and adult-
each with its own peculiarity of habit and form, although the adult and
pupa resemble one another much more than do the adult and larva ; but
no matter how dissimilar the larva, pupa, and adult may outwardly
seem, structures common to them all may be traced throughout. Make,
for example, a comparative study of the larva, pupa, and moth of the
magpie moth; the head, thorax, and abdomen can be seen in each stage,
while counterparts of the larval antennae, eyes, mouth-parts and feet
persist in the moth, though more or less profoundly modified during
pupal transformation. Although there are no external signs of wrings
in the larva,, these appendages are developing, nevertheless, in concealed
"pockets" within the larval thorax, and, at the time of pupal formation,
become extruded and lie ensheathed with the legs and antennae in the
pupal cuticle along the sides of the pupal body. Apart from these
changes, the larval mouth parts undergo a most profound metamor-
phosis; apparently, though there is no similarity between the long
"tongue" or proboscis of the moth and the jaws and accessory jaws of
the caterpillar, the proboscis, adapted for sipping the nectar of flowers,
is nothing but the accessory jaws of the leaf-chewing larva greatly
elongated ; with the exception of the palpsl of the accessory jaws, the
other larval mouth parts are either absent in the moth or reduced to
vestiges.

In the case of insects that develop without a metamoTphosis, the
life-cycle is one of comparative simplicity. An example of such an
insect is the so-called "silverfish" (Lepisma s&ccJiarina), common in
dwellings, especially in damp places, dark and dusty corners, flour and
sugar bins, while not uncommonly it causes some considerable damage
by devouring the paste and glaze from wallpapers and the binding and
leaves of books.

The silverfish (Fig. 4), wingless1 throughout life, measures about
one-quarter of an inch long when full grown ; it is silver-white in
colour, due to a clothing of| glistening scales that rub off as a silky
powder when the insect is handled. It glides rapidly about, especially
after dark, and is one of the most primitive insects, there being minute
leg-like processes attached in pairs to the under side of the abdomen;
the normal thoracic legs are well developed. The body is wedge-shaped,
tapering to the posterior end, from which three tail-like appendages
project, while anteriorly a pair of long, delicate antenna? arises from
the head.

All stages of the silverfish, from the minute, freshly-hatched indi-
viduals to fully-grown ones, may be found in the one place, the smaller
ones being immature developing stages. In the case of another species
allied to the1 common silverfish, the female lays from six to ten eggs
at one time in sheltered crevices, and the young hatch forty-five to sixty
days later, when the temperature ranges from 65 degrees to 68 degrees
Fahrenheit.

Unlike the moth larva, that of the silverfish throughout its growth
resembles the adult both in habit and form, the only marked differences
being that of size and the absence of the abdominal leg-like appendages.
During growth several moults take place, and at the final one the adult

26

GARDEN PESTS IN NEW ZEALAND

appears with all its characteristics. Some species take two years to
reach maturity. In this type of insect there is, therefore, no pupal or
resting stage, and the larval habits and food are the same as those of
the adult insect, while there is but little difference in structure through-
out all the stages.

There are many winged insects (e.g., cockroaches, crickets and
earwigs) that show a slight advance toward a metamorphosis. Though
their larvae differ from the adults principally in the absence of wings,
there are stages between the younger larvae and the adults in which the
wing rudiments appear. These rudiments first appear after one of the
moults as small bud-like structures on each side of the thorax (earwig,
Fig. -t), becoming larger after each succeeding moult, when the
developing wings may be seen enclosed in a sheath of the cuticle; ait
the final moult the wings, no longer enclosed in their coverings,
straighten out and become functional. A very pronounced difference is
here noted between the wing development of such insects and that of a
moth, in that the wing rudiments of the former develop externally and
those of the latter internally.

A decided advance toward a metamorphosis is exhibited by insects
known, as thrips (Fig. 4). Though readily overlooked on account of
their minute size (one-twenty-fourth of an inch and less), they are
nevertheless conspicuous on green foliage and white flowers owing to
their blackish or yellowish colour. Thrips, when magnified, are easily
recognised by their peculiar wings; each is feather-like, being formed
of a narrow rib-like membrane clothed along the margins with long
and delicate stiff hairs. Thrips' eggs are laidjipon the plant surface
or within the tissues, according to the species, and are very minute
(about one-twenty-third of an inch long). The larvae puncture the
plant tissues and feed upon the juices just as do the parents, which they
resemble in general form, except that there are no wings and the
antenna? are very short and the eyes small. There are two or three larval
moults, after which the insect is more like the adult, though still
resembling the larva. It now differs from the latter, however, in the
antennae being considerably shortened, and in the appearance of a pair
of finger-like processes on each side of the body attached to the thorax
and lying along the sides of the abdomen ; these processes are the sheaths
enclosing the wing rudiments of the future adult. The insect again
moults, changing to a form resembling the preceding stage in many
respects, but differing in the wing sheaths being much longer, and in
having the antennae, enclosed in sheaths of cuticle, turned back over
the head. Although during these two stages the insect is capable of
moving about, it is nevertheless sluggish and does not feed; from this
second semi-quiescent stage the adult emerges. In the thrip's cycle,
therefore, although the habits of the larva and adult are similar, the
presence of the two intermediate semi-quiescent stages, during which
feeding ceases, shows a decided advance toward a true metamorphosis
and represents a pupal stage.

In the case of those insects not involved by a metamorphosis, as
discussed above, the structure and habit of both adult and the immature
stages differ but little, the development of wings being the principal
change, except in the case of the thrips, where there is a definite
tendency toward a pupa. However, passing on to a consideration of

27

GARDEN PESTS IN NEW ZEALAND

the common cicada (wrongly called a locust), a change in both structure
and habit occurs during the life-cycle, the immature stages being adapted
to a subterranean life, while the winged adult frequents the foliage of
trees; all stages agree, however, in puncturing plant tissues with their
proboscis and sucking up the nutrient juices from the roots by the larva
and from the stems and leaves by the adult.

The female cicada (Fig. 4) lays its eggs in colonies beneath the
young bark of trees and shrubs; the larvae, on hatching, drop to the
ground, into which they burrow ; the antennae and soft body are com-
paratively long, while the fore legs are greatly modified for grasping-
plant roots and as digging tools. After a number of moults, the body
shortens, the antennas come to resemble those of the adult, and the
rudiments of the wings appear. Growth and the activities of the
developing insect continue until finally the larva constructs an earthen
underground chamber, in which it lies torpid until ready to undergo the
final moult; in this inactive state, though still resembling the later
larval stages, the insect corresponds to the pupa of the moth. For the
final moult the pupa leaves the ground, crawls up some support (a tree
trunk or post), where the winged adult emerges, leaving the empty
pupal husk attached to the support. Besides the change in habit and
the possession of functional wings, the adult cicada differs in many
structural features from the immature stages. Outstanding differences
are the normal fore legs, the development of a "voice-box" in the male,
and an ovipositor in the female.

An insect that shows some linkage between those having a true
metamorphosis and those having a partial metamorphosis is the aphis-lion
(Micromus tasmcwice), though undergoing a true metamorphosis itself.
The larvae are predaceous and feed upon aphids (Fig. 4). Its larva,
pupa, and adult are distinct forms, as in the moth, but the larva is not
of the specialised caterpillar or grub type, rather resembling in general
appearance the silverfish, or the type of young larva peculiar to such
insects as the earwig or thrips before the wing rudiments develop.
Furthermore, the pupa, though one in the strict sense, is capable of great
freedom of movement, its head, mouth-parts, antennae, legs and wings,
ensheathed by the cuticle, being freely movable, and not rigidly attached
to the body.

A review of the early larval stages of the earwig, thrips and cicada,
prior to wing development, and of the aphis-lion larva, shows a con-
formity to a generalised type exemplified by the primitive silverfish. On
the other hand, the moth caterpillar exhibits another larval type more
highly specialised, though still retaining a modified semblance to the
silverfish type, while specialisation is carried to the highest degree in
the blowfly maggot, where all outward sign of the primitive larval type
is lost, Regarding the pupae, there are three types; the most simple i^
the free pupa, like that of the aphislion, and some moths, beetles, etc.,
where the appendages are freely movable. The most complex is the pupa
of the blowfly, enclosed in its puparium, while intermediate between
these two extremes are many moth pupae that have the appendages firmly
attached to the body, but nevertheless visible.

GARDEN PESTS IN NEW ZEALAND

CHAPTER V.

Sucking Insects.

THE term "sucking insect" is applied to all insects that have the
mouth parts modified as delicate stylets, by means of which the
plant tissues are punctured and the nutrient sap sucked up. Not only
may such insects weaken the infested plants, but they also cause the
destruction of chlorophyll, interfere with the normal functioning of the
stomata, and have a toxic effect upon .the tissues; further, many sorious
plant diseases are earned and spread by sucking insects, whilst the
punctures made when feeding may allow the entry of disease spores.

Among sap-sucking insects are scale insects, mealy-bugs, aphids.
leaf-hoppers, white-flies, thrips, etc. Infestation by most of these
insects (especially in the case of scale insects, mealy-bugs, and aphids)
is very often detected by the sticky nature and blackened appearance
of the plants; this is due to the fact that the insects excrete a sweet,
sticky substance known as "honey-dew," which collects! on the foliage
and branches, whilst upon it grows a black, sooty mould.

Scale Insects and Mealy-bugs.

Scale insects and mealy-bugs, collectively known as coccids, are of
very great economic importance on account, not only of their widespread
depredations upon plants, few being free from infestation, but also of
the commercial value of some species — e.#.; in the production of lac.
cochineal, Chinese wax, etc. ; it is with the injurious forms that the New
Zealand horticulturist is concerned. The term "scale insects" is derived
from the appearance of many of the species that are protected by a
scale-like covering, which forms a conspicuous scaly incrustation when
a plant is heavily infested.

Of the several kinds of insects injurious to vegetation, the coccids
as a family are undoubtedly of major importance, because they infest
not one group, or allied group, of plants, as do so many other injurious
insects, but an extensive range of widely different plants. Some coccids
are much more injurious than others, the San Jose Scale, for example,
having a very virulent toxic influence, while the Greedy Scale may
cause but little damage, even when the plant is completely encrusted by
it; further, some plants may be more susceptible to injury than others
by the same species of coccid.

Coccids, as a whole, are highly specialised insects, and among
themselves exhibit a great variety of forms. Throughout the group the
sexes differ to a marked degree. The adult males, which vary but little

29

GARDEN PESTS IX NEW Z E A L A X D

in all the coccids, are usually minute, and, with few exceptions, two-
winged (Fig. 5) ; none has mouth parts, these appendages having become
atrophied during metamorphosis, which is complete, while many have
one or more hair-like tail appendages. On the other hand, females are
never winged ; some are comparatively large ; all have well-developed
mouth parts throughout life, and undergo incomplete metamorphosis,
while in many forms the legs and antennae are lost before maturity.

In all cases coccids secrete a protective covering, which assumes
different forms; this fact, together with the chief methods of female
development, is utilised for the purpose of this work to arrange the
coccids under three main types as follows : —

1. LESS SPECIALISED FORMS. — Examples are the mealy-bugs and
cottony-cushion scale, which belong to the more generalised or least
specialised representatives. The protective body covering is in the form
of a powdery or mealy secretion; the legs1 and antennae are retained
throughout life, and the insect remains freely mobile.

A typical-form life-cycle may be studied in that of the cottony-
cushion scale (Figs. 5 and 6a). During development the female insect
passes through three larval stages; each of these stages is, on the whole,
similar, except for size and minor structural changes, and the white
powdery secretion that covers the reddish body of the adult.

2. INTERMEDIATE FORMS. — An example is the olive scale (Fig. 5).
In such forms there is a tendency to specialisation, owing to more or
less sedentary habits in later life, and protection is afforded by a thicken-
ing and toughening of the cuticle on the upper surface of the body
Unlike the cottony-cushion scale, the female olive scale passes through
two larval stages ; the minute first stage larva is active and very flat ; it
soon settles upon a leaf and commences to feed, when it becomes much
flatter and a little larger; the second stage differs from the first in size
and in the development of a dorsal longitudinal ridge, which eventually
forms the cross-bar of the two transverse ridges that are characteristic
of the third or adult stage, when the insect swells and assumes the shape
of the mature form. After settling in the first larval stage, the insect
becomes very sluggish, and does not move, except to migrate, as most
do, from the leaves to the twigs, there to take up a permanent position.
The legs and antennae are retained throughout life, but in the adult are
functionless, being folded against the body; in some species of inter-
mediate forms the appendages become atrophied during development.
In the olive scale, and related forms, the toughened cuticle not only
serves as a protection to the insect, but also as a receptacle for the eggs
(Fig. 5) ; as these are laid and increase in numbers, the* body of the
parent diminishes and is crowded against the dome-shaped cuticle.

3. SPECIALISED FORMS. — The apple mussel-scale (Figs. 5 and 7,
Nos. 2 and 6) is a representative of this group, the members of which
are markedly specialised, the legs and antennae of the adult female
becoming completely atrophied during development, and the shape of
the body profoundly altered; protection is afforded by a scale-like
covering not attached to the body. In the mussel-scale development
there are two larval stages: the first, like all coccids, has the legs and
antennae well developed and is active.

30

GARDEN PESTS TX NEW ZEALAND

On settling- to feed, this first larva commences to produce a covering
of white threads that mat together -to form the first scale ; the second
stage larva presents profound changes in the absence of legs and
antenna?, while the body has become pear-shaped, the head, thorax and

Male

Pupa

Adult

Cottony Cushion 3cale
-Adult

Olive

e over-
awed Snowin
adu.lt 9- eggs

Jan ose' Stole
Quaintar.de)

FIG. 5. — ILLUSTRATIONS OF DIFFERENT TYPES OF SCALE-INSECT
LIFE-HISTORIES.

31

GARDEN PESTS IX NEW ZEALAND

abdomen seeming as one-; a second more waxy scale is now formed.
After a second moult, the adult appears, and resembles the second stage
larva in form ; the adult constructs a third scale, very much larger than
the earlier ones, to which it remains attached by its anterior end.

Though many of the specialised coccids form elongate scales, as in
the case of the mussel-scale, numerous others construct circular scales,
as does the San Jose (Fig. 5) ; in the latter, the second and third scales
are constructed round the first, so that the first and second appear as
pimple-like structures in the centre, or slightly to one side of the com-
pleted covering. As with the olive scale, the covering of the specialised
forms serves as a receptacle for the eggs (Fig. 5).

Some of the more important coccids occurring in ]STew Zealand will
now be discussed.

CQTTOXY CUSHION S.CALE (Icerya pwrchasi). — This insect (Fig.
6a) is a native of Australia, but has now become established in many
other countries, including New Zealand. For a time it was a serious
pest of citrus, until the introduction and establishment of its natural
enemy, the ladybird beetle (Novius cwrdinalis).

The adult female is more or less oval, and covered with a yellowish
powder, partly concealing the reddish-brown ground colour and dark
spots along the sides of the body; the legs are black. A characteristic
feature is the white corrugated egg-sac attached to the end of the body
(Fig. 5). As the eggs are laid, this sac increases 'in size, until it may
measure fully 2-J times the length of the parent, which becomes tilted
up. The eggs are orange-yellow, and as many as 800 may be produced
by a single female. The eggs hatch in about a fortnight during summer,
and the period of development to the adult ranges from three to five
months. The larvae most frequently congregate along the mid-ribs of
leaves, and as development advances they usually migrate to the twigs
and branches. There are two generations each year. A considerable
variety of plants is attacked by this insect, chief among which are citrus,
acacia, gorse, wattle, and Douglas fir.

Control is effected by the agency of the ladybird, but epidemics
sometimes occur with which the beetle cannot immediately cope; in such
a case fumigation in the glass-house, or spraying with red oil in the open,
should be resorted to.

MEALY BUGS. — Mealy bugs are characterised in the female by the
nature of the waxy protective secretion which forms a powdery meal-
like covering over the body, but is developed as a fringe of leg-like
processes at the side (Fig. 6b) ; these processes at the posterior end of
the insect may be prolonged as longer or shorter tail-like appendages in
some species, or they may be no longer than those fringing the body
margins in others. Immediately after each moult the larvae are devoid
of mealy covering and lateral processes, which are secreted anew each
time the cuticle is shed. In a mealy bug colony are numerous small,
narrow cocoons, in each of which a developing male 'insect lies.

Most mealy bugs produce eggs, which are laid in a spacious, cottony
sac secreted at the posterior end of the female; the female insects, egg
sacs, and male cocoons together form characteristic woolly masses on
infested plants.

32

l>v mealy I>UL>'S nia\" l>e Gioiisiclei'abie, not onlv
f |il;ii)i sap.-])ui nlso owin^ to the product ion of

) ;MjU(M!l SOOtV l!)Olll<l. All | )fl I'tS ()f plfllltS MF6

attack, and the injects aio !'re(|uently attended

(;i i Cotldiy en-;1 ion s-'cale. (l>> Mealy bujj. ( c ) The Mack olive scale. dl> flum troo

s.cah- : On :i';'ht, females on twig; upjier left, male scales; lower left, t'ie ladybird

beetle; centre, scales destroyed by beetle. (e) Hemispherical scale.

(f) Fruit lecanium scale.

. Hurl''*, Cuwtlii'OH Institute.

33

G A R I) ]•: X P K S T 8 1 X X E \V Z K A L A X 13

Mealy bugs are controlled to a great extent by natural onemies,
among which are the Tasmanian lace wing (Mlcromu* las mania?) and
the Cryptola^mus ladybird (GryptoUemus montrouzicii), but the
influence of these is insufficient for commercial purpose-. Attempts are
now being made at the Cawthron Institute, Nelson, tc establish other
parasites recently imported from California.

Control under glass is effective by means of fumigation, but in the
open is a more difficult matter, though red oil and lime-sulphur give
some satisfactory results, together with the pra ' rice of removing rough
bark on trees where the insects hibernate. In Xew Zealand are several
species of. mealy bugs, of which the following are of interest to the
horticulturist : —

LOXG-TAILED MEALY Bra ( Pseudoc0ccnx a 'Ion >!>ii m ) . — This species
is readily recognised by the long tail-like appendages of the female. It
is widely distributed and commonly met with under glass, where it
infests almost any plant; in the warmer and moister districts of the
Dominion it occurs out of doors. Its list of host plants is a lengthy one,
and includes grape vine, passion vine, wistaria, fig, oleander, Phorniiumr
cineraria, begonia, apple, plum, palms, ferns, etc. Considerable injury
may be caused by the insect when it occurs in dense masses on the under
side of foliage and upon young, succulent growth.

Xo eggs are produced by this insect, the young being born alive ;
the production of young lasts for a period of from two to three weeks
at the rate of about twelve each day; the time taken to reach maturity
varies considerably, according to climatic conditions, the range being
from one to three months. There are comparatively few generations
each year out of doors, but under glass there may be several.

CITROPHILUS MEALY BUG (Pseudoco:cus galiani). - - In Xew
Zealand this -species is met with on grape vines and begonia in glass-
houses, where it becomes epidemic if left uncontrolled ; out of doors it
infests apple and potato, and no doubt other plants are attacked. It is
characterised by the mealy covering being coarse and distributed
unevenly over the body, while the marginal fringe is short, the processes
being comparatively thick, particularly the tail-like ones, which are much
shorter than the body, though conspicuous.

Egg-laying covers a period of about two weeks, from 394 to 679 eggs
being deposited by each female ; development to the adult is completed
in about six weeks, though this will vary according to the conditions.
In California four generations in the year have been noted.

APPLE MEALY BUGS (Pseudococcus maritimus and P. comstocki). —
Both these species occur upon apple, pear and potato in Xew Zealand, the
former species originating in America, and the latter in Japan; the
injury to the host itself is not severe, but the presence of these insects
on the fruit is responsible for apples and pears being rejected for export.

Both species are very similar in appearance, and are of the short-
tailed type; they differ from the citrophilus mealy bug in having the
mealy covering evenly distributed over the body, while the marginal
fringe is delicate and thread-like. The eggs hatch in from one to three
weeks, and the larvae migrate freely, the insects reaching maturity one
or two months later, according to climatic conditions. In the open the

34

GARDEN PESTS IN NEW ZEALAND

winter is passed in the egg stage, but under glass or in mild climates
activity among the different stages- occurs throughout -the year.

Apart from apple and pear, these insects have been recorded from
many plants : Baker's mealy bug (maritimm) on lemon, orange, walnut,
willow, elder, ivy, iris; and Comstock's mealy bug on citrus, elder,
euonymus, gooseberry, grape, horse chestnut, hydrangea, mulberry,
peach, persimmon, plum, poplar, wistaria.

THE GUM SCALE (Eriococcus coriaceus). — This is one of the most
spectacularly destructive scale insects now established in the Dominion,
It is a native of Australia, and its normal hosts are the several species
of eucalyptus, though it is sometimes found on apricot and willow. A
characteristic feature of infected eucalyptus is their blackened appear-
ance, due to sooty mould growing on the copious honey-dew secreted
by the scale.

On an infested twig or branch, the insects may be so closely packed
as to conceal the bark (Fig. 6, d) ; each female lies in a pear-shaped sac
of felted secretion, reddish-brown, tawny, or sometimes white in colour,
measuring about three-twenty-fifths of an inch long, and having a
circular aperture at one end. The enclosed insect is somewhat flattened,
oval, and blood-red in colour; when crushed, it leaves a reddish and
sticky smear. The developing males are to be found forming white
patches of innumerable individuals on the tree trunks under the loose
bark (Fig. 6, d).

The female is viviparous; during spring, mid-summer and autumn
immense numbers of young are produced, which, escape through the
opening at one end of the female sac, and are carried long distances by
the wind. These young insects first settle on the eucalypt leaves,
whence they migrate, the females to take up their final position on the
twigs and smaller branches, and the males to continue their development
on the trunk of the tree.

The gum tree scale occurs throughout the districts east of the
Southern Alps and in the vicinity of Xelson, in the South Island, and
over the southern half of the Xorth. Island; it is, however, spreading
rapidly northward.

This pest is held in control by means of the black-ladybird beetle
(Rhizobius ventmlis) — Fig. 6, d — which was imported for the purpose
from Australia; birds such as the tui, wax-eye, fantail, blackbird and
thrush congregate on infested trees and eat the insect.

OLIVE SCALE (Saissetia olece). - This insect has a world- wide
distribution, and is one of the most important pests of citrus in New
Zealand, although it occurs on a wide range of plants; in all cases it
infests the fruit, bark, and the under side of leaves. The host plants
include citrus, apple, pear, apricot, plum, almond, fig, grape-vine,
wistaria, pepper tree, oleander, holly, laurel, palms, camellia, rose.

The injury caused by the insect is not so much on account of its
weakening influence upon the infested plants as of the fact that it
copiously secretes honey-dew, so that black mould develops to* a marked
degree, necessitating the washing of herbaceous plants and fruit.

The adult female (Fig. 6c) is hemispherical, and measures about
one-fifth of an inch in diameter, a characteristic distinguishing feature

35

GARDEN PESTS IN -NEW ZEALAND

being the three ridges forming the letter H on its upper surface (Fig. 5).
According to age, the colour varies from brownish or greyish to jel
black, the insect being conspicuous against the lighter background ot!
bark or leaf; the small, immature individuals are light brown or
yellowish, and almost flat.

In New Zealand the winter is passed in both egg and larval stages.
though a few adults may be found at that time ; on turning over what
appears to be an adult, it will usually be found that the female has died
and her place taken by numerous eggs (Fig. 5). The average number
of eggs produced has been estimated at from 1,500 to 2,000 per female ;
at first the eggs are white, but prior to hatching they turn a, deep orange-
red. Development is slow, the adult state being reached about three
months after time of hatching; egg laying commences about five weeks
after maturity, and continues for a period of about six weeks. There is
only one generation each year, and all stages may be met with on the
one plant; the greatest activity occurs during the summer months. An
important natural enemy of this scale is the steel-blue ladybird beetle
(Orcus chalybcem), introduced from Australia.

HEMISPHERICAL SCALE (Sa/issetia hemispherica) . — This wrorld-wide
species is commonly met with in New Zealand, and, though not a serious
pest, has a wide range of host plants, both in the open and under glas- :
some of the commoner hosts are citrus, fig, oleander, palms, japonica,
camellia, asparagus, and orchids.

Both leaves and stems are infested by the insect, which resembles
the olive scale (Fig. 6e) ; from the latter it may be distinguished by its
light brown colour and smooth surface, there being no ridges ; the longest
diameter of the adult female is one-seventh of an inch. Between 500
and 1,000 eggs are laid by each female, and the life-cycle is completed
in about six months ; the young insects settle along the main leaf- veins.

TURTLE SCALE (Coccus liesperidum ) . - - This widely-distributed
insect, though common in hot-houses and out of doors in the warmer
parts of the Dominion, is not especially injurious, except for the copious
honey-dew secreted and the consequent sooty mould; it occurs on holly,
ivy, camellia, citrus, laurel, myrtle, oleander, and japonica.

The insect infests leaves and stems, and is especially abundant on
succulent growth. The adult female is rather reddish-brown in colour,
dome-shaped, but with the margins flattened on the host plant; on each
side the margin is notched by a shallow depression, and there is a deeper
one at one end; over the surface is a reticulation of ridges, resembling
the pattern on the back of a turtle ; fully-developed individuals measure
from one-sixth to one-eighth inch in diameter. This species is vivi-
parous, and development to the adult occupies about nine weeks; there
may be three or four generations each year.

FRUIT LECANIUM SCALE (Eulecanium corni). — This European
insect is common throughout the Dominion, where occasionally it
becomes epidemic and causes some temporary damage; with it are
associated honey-dew and sooty mould. Among the plants infested are
apricot, peach, nectarine, plum, pear, grape-vine, wistaria, raspberry,
mulberry, blackberry, gooseberry, black currant, ferns.

36

GARDEN PESTS IN NEW ZEALAND

Leaves and bark are infested., and a narrow twig may be partly
encircled by the margins of the scale. The adult female (Fig. 6f) is
oval and dome-shaped, some individuals measuring one-sixth of an inch
in length; the surface is smooth, except toward the margins, parallel to
which are some wrinkles. The general colour is dark brown, but just
prior to egg-laying there are numerous transverse and longitudinal
markings of a lighter colour over the surface, The. winter is passed in
the egg stage or as partly-grown young.

Another, but larger, species, closely resembling the preceding, and
found 011 grape-vines, wistaria, eleagnus, etc., is Eulecanium berberidis.
It is reddish-brown in colour, and measures up to one-third of an inch
in length.

GOLDEN OAK SCALE (Asterolecanium variolosum). — This insect is
very common upon English oak trees in parts of New Zealand. In many
cases so badly are the trees infested, that they become sickly in appear-
ance, and at times the greater part, or even the whole, of the tree is killed
through the agency of the pest.

The individual scale (Fig 7, 1) is more or less circular, and about
one-sixteenth of an inch in diameter; it is of a greenish-yellow colour,
with a narrow paler circumference, though some, with the exception of
the rim, are partly or wholly brownish. Each scale forms and lies in a
depression of the bark. The insect is viviparous. A minute parasite,
Hub role pis dalmanni (note the exit holes made by the parasite during
emergence from some of the scales shown in the photograph) has recently
been established as a means of control and is proving effective.

CAMELLIA SCALE (Pulvin&ria camelicola). — This European scale
sometimes heavily infests camellias and euonymus in New Zealand, but
is not a very serious pest, though more so in glass-houses than out of
doors. After the female has produced her eggs, she drops off the plant,
so that, though the latter shows evidence of injury, there may be no sign
of the insect.

The adult female is oval and about one-third of an inch at its
longest length ; in shape it resembles a rather flattened turtle scale, hut
when laying eggs the body shrivels and numerous transverse wrinkles
develop, although the margins of the scale remain smooth. There is at
least one generation each year, and in warmer parts probably a second,
which may reach maturity before winter or not till the following spring.
The eggs are laid in an elongate, white, cottony sac secreted at one end
of the female ; this sac is sometimes as much as four to five times the
length of the insect. The eggs continue to hatch over a period of from
four to six weeks, and the larvae rapidly spread; the latter settle along
the leaf mid-rib, margin, or lower surface.

APPLE MUSSEL SCALE ( Lepidosaphes ulmi). - - The apple mussel
scale is now established throughout the temperate regions of the world.
It is commonly met with on apple, but has a long list of host plants,
among which are pear, hawthorn, willow, poplar, -gooseberry, and currant.

The insect (Fig. 7, Xos. 2 and 6) forms incrustations on bark
and fruit, and is commonly met with at the stalk end of the apple; the
individual scale is chocolate-brown in colour, is shaped like the shell of
the salt water mussel — hence the name "mussel scale" — and when full
grown measures one-eighth of an inch long.

37

GARDEN PESTS IN NEW ZEALAND

A single female is capable of laying up to 700 eggs, in which stage
the winter is passed. The eggs hatch in the spring, and the young insects
swarm over the host plant in search of a suitable place to settle. A
continuous warm spell of weather in the spring will allow all the eggs
to hatch almost at one time, but alternating cold spells will retard
development, so that emergences take place over a longer period. After
emerging from the egg . until maturity, when egg-laying again takes
place, a period of three months elapses ; the insect is a slow breeder, and
produces only one brood a year in colder climates, but is two-brooded
in warm districts, such as Auckland.

A small hymeno-pterous parasite (Aphelinm mytilaspidis), less
than one-twenty-fifth of an inch long, attacks this scale, but does not
serve as an efficient control; individual scales that have been killed by
the parasite show a small hole through which the adult parasite has
emerged. The most effective control is secured by treating infested
trees with red oil or lime-sulphur during winter.

CABBAGE TREE SCALES (Leucaspis cordylinidis and Leucaspis
strict®). — Cabbage trees and also New Zealand flax often have the leaves
encrusted by the white masses of these two native scales. The adult
female of "one species (L. cordylinidis) measures one-eighth of an inch
long, is very narrow and straight as a rule, and white in colour, except
for the yellow anterior end (Fig. 7, 4). The other species (L. stricta)
resembles the former, except that the adult is one-eleventh of an inch
long, and has the anterior half blackish. In the case of ornamental
cabbage trees and flax, control can be effected by removing all dead and
scale-infested leaves, thus allowing access to sunlight.

SAN JOSE SCALE (Aspidiotus perniciosus). — Of all scale insects of
major importance, the San Jose (Fig. 7, 5) is outstanding, in that it is
one of the insects most destructive to deciduous trees and shrubs, a con-
siderable number of which are liable to attack. It is of Chinese origin,
and first came into prominence when it became established at San Jose,
in California, hence its name. Owing to its small size, it is easily
overlooked, except when epidemic, and is readily transported upon plants
from one country to another.

The list of plants attacked is a long one, but the following may be
mentioned: — Acacia, hawthorn, quince, privet, poplar, almond, apricot,
cherry, plum, peach, pear, apple, gooseberry, currant, roses, willow,
ash, elm.

The female San Jose scale is circular in outline, having a diameter
of about one-twenty-fifth of an inch ; in profile it has the form of a flat
cone with a crater-like depression at the apex, in the centre of which
lies a minute pimple-like prominence; the immature scales are smaller
and whitish in colour, while the male scale is elongate-oval in outline,
with the crater-like depression toward one end. The individual scales
are greyish and are readily overlooked, but when well established upon
a tree they form an incrustation giving a characteristic dull silver-grey
appearance to the tree; bark, fruit and leaves are infested. A char-
acteristic feature of San Jose scale infection is the discolouration of the
plant tissues immediately surrounding each insect, which turn a distinct
red or purple, giving at once an indication that this scale is present.

38

GARDEN PESTS IN N E W ZEALAND

The winter is passed by the insect in almost a mature state ; on the
advent of spring, development to maturity continues, when, after mating,
the females give birth to living young over a period of several weeks.
The young reach maturity and commence to reproduce five to six weeks
from birth, there being several generations in the course of a season.
The average number of young produced by each female has been found
to be about 400.

FIG. 7.

(1) Colden Oak Scale; (2) Apple Mussel Scale; (8) Black Scale; (4) Cabbage Tree

Scale; (5) San Jose Scale; (6) Apple Mussel Scale; (7) Oleander Scale;

(8) and (9) Rose Scale.

Photographs by W. C. Davies, Cawthron Institute?

39

GARDEN PESTS IX XEW ZEALAND

Natural enemies in Xew Zealand are two species of hymen opterous
parasites, Aplielinus fuscipennis and A. mytilaspidis, the latter^ also
attacking the apple mussel scale. Ladybird beetles also feed upon the
insect.

- Control requires close attention, and can be effected by the applica-
tion of lime-sulphur in the dormant season, when it is essential to apply
a strong wash to kill off as many scales as possible before reproduction
commences in the spring. At bud movement further applications are
necessary to destroy the young insects.

A

BED ORAXGE SCALE (Chrysomphalus nurantii). — The red orange
scale is distributed throughout the world, and is especially abundant in
tropical and sub-tropical regions, the most southern limit being Xew
Zealand. As a major pest it is peculiar to citrus, but infests to a minor
extent other plants — e.g., plum, apple, pear, quince, grape, fig,
euonymus and rose. So far it has been found only on citrus in New
Zealand, it being well established in the Auckland province, and also in
the South Island on Banks Peninsula. It is very often found on
imported oranges and lemons.

This scale is a circular one, with a central pimple-like prominence,
as in the case of the San Jose, but is natter, about half as large again,
and is of a characteristic reddish colour. The damage done to citrus
trees by this insect is of a serious nature, as the entire tree or part of
it may be killed in severe infestations. A characteristic feature of this
species is that no honey-dew is secreted, and hence there is a total absence
of sooty mould on infested trees.

Like the San Jose scale, the red scale is viviparous, and over-
winters as partially mature adults, completing development in early
spring, when the young insects make their appearance. An average of
about 55 young is produced by each female, and development to maturity
takes from two or two and a-half 'months; about one month later young
are produced, and their production continues over a period of one or two
months; climatic conditions, however, have a direct influence on
development.

An important natural enemy is the steel blue ladybird (Orcus
chalybmus) , imported from Australia; but the most efficient control is
cyanide fumigation, or spraying with red oil or lime-sulphur.

THE BLACK SCALE (Chrysomphalus rossi). — Foliage of palms,
oleander and citrus is often infested by this reddish-black to black
circular scale (Fig. 7, 3) ; it is almost flat, with a central whitish spot,
and measures up to one-tenth of an inch in diameter ; when many indi-
viduals are crowded together, their outline becomes irregular. This
species is not especially injurious, though common.

OLEANDER SCALE (Aspidiotus hederce). — This cosmopolitan insect
occurs on orchids, oleander, ivy, camellia., palms, citrus, coprosma, and
karaka, infesting stems, leaves and fruit. In the case of citrus, this
insect delays colouring of the fruit, which becomes blotched with yellow
or green. The insect may be so numerous, that it completely covers the
whole plant, giving to the latter a white appearance; this is due to the
preponderance of white male scales, the female being slightly yellow,
with a purplish tint.

40

GARDEN PESTS IN NEW ZEALAND

The female scale is almost circular (Fig- 7, 7), having a diameter
of from one-twenty-fifth of an inch to two-twenty-fifths of an inch, and
is rather flat; the male is more oval and of the same size, and in both
cases there is a central orange-yellow spot. The eggs are comparatively
large,, and hatch soon after being deposited. The insect reaches maturity
in from four to six weeks.

GREEDY SCALE (Aspidiotus rapax). — This European insect is now
widespread, and in New Zealand is common on apple, pear, quince, and
wattle ; it has a wide range of hosts. The adult female scale is convex
and of a general grey colour, though sometimes yellowish. The winter
is passed in all stages of development.

HOSE SCALE (Aulacaspis rosce). — This is a very common insect,,
forming white incrustations on the bark of roses, briar, raspberry, logan-
berry, blackberry, and sometimes pear. The adult female (Fig. 7, 8),
which is from one-twelfth of an inch to one-eighth of an inch in
diameter, is rather thin and flat, circular or oval in outline, but irregular
when crowded; the general colour is white or slightly yellowish. The
male (Fig. 7, 9) differs, in being elongated and narrow. This insect
can withstand severe winters, and is to be controlled by the use of
red oil.

GARDEN PESTS IN NEW ZEALAND

CHAPTER VI.

Sucking Insects — (Concluded).

Plant Lice, or Aphides.

THE small, soft-bodied plant-lice, or aphides, usually found forming
dense colonies on all sorts of plants, are pests well known to every
gardener; they attack plants by inserting into the tissues their delicate
piercing mouth-parts, and drain the nutrient sap (Fig. 8, Ig). All
parts of a plant may be infested, and the insects, owing to their ability
to reproduce abundantly and rapidly, may destroy the plant, or at least
injure it by stunting its growth, curling the leaves, or deforming the
flowers and fruit. In many cases aphides copiously secrete honey-dew,
upon which sooty mould grows, rendering the plant unsightly; on this
honey-dew ants feed, and are frequently seen associated with aphides.
Apart from their direct injurious effects, aphides are of outstanding
importance, in that they transmit some of the most serious plant diseases.
Of all the species occurring in Xew Zealand, only one species is supposed
to be a native.

Most aphides live exposed upon the host plant (e.g., Rose Aphis),
but some (e.g., Woolly Aphis) secrete a protective covering, while others
cause a malformation of the plant tissues which form a partial protec-
tion as a semi-gall (e.g., Elm-leaf Aphis), or a complete protection as
a true gall (e.g., Leaf-petiole Gall-aphis of Poplar).

Aphides present certain variations in structure, and, generally
speaking, the one species presents four or five types (Fig. 8, 1) : the
asexual (parthenogenetic) wingless and winged females that give birth
to living young (viviparous) in the absence of males, and the sexual
forms, both males and females, the latter producing eggs (oviparous).

The best character by which the Xew Zealand aphides are to be
recognised is to be found in the pair of longer or shorter hoirn-like
processes, or "cornicles," projecting from the upper surface of the
abdomen; in some species, however, the "cornicles" are reduced and
inconspicuous (e.g., Woolly Aphis), or altogether absent (e.g., Grape
Phylloxera).- The "cornicles" are frequently called "honey-tubes," since
for many years it was thought that they secreted the honey-dew; it has
been shown, however, that the honey-dew is secreted from the rectum,
and that the function of the "cornicles" is to secrete a waxy protective
substance, which may take the form of a powder or woolly threads. Th»>
wings, when present, are membranous, the front pair being much larger
than the hind ones, and when not in use usually close roof -like over the
bodv.

GARDEN PESTS IN NEW ZEAL A N D

FIG. 8.

<1) Life History of an Aphis: A, egg; B, C, and F, wingless females; D, winged female;
E, male; G, section of head and plant tissue to show method of attack. (2) Life History
of a Leaf-Hopper: II, eggs under bark of twig; I, first stage hopper; J, later stage
hopper with developing wings ; K, adult from above ; L, adult from side. (3) Life History
of a White Fly: M, egg; N, first stage larva; O, pupal stage under scale covering;
P, adult. (4) An adult Thrips.

43

GARDEN PESTS IX NEW ZEALAND

In their life-histories and habits aphides present many variations,
sometimes of considerable complexity, but fundamentally the processes
are as follows: — Eggs are laid on the host plant during the autumn,
and give rise to windless females in the spring; these females (being
asexual or parthenogenetic, since they reproduce without being ferti-
lised) a?e viviparous, producing living forms similar to themselves.
Some of these forms remain wingless, while others may develop wings,
upon which a wider dispersal of the species depends, but in both cases
such females are asexual and viviparous. Several such generations ma}r
develop until the autumn, when males and females appear, the latter
being oviparous, producing the over-wintering eggs when fertilised by
the males. Very often, however, the life-cycle is considerably compli-
cated by the winged forms flying to other host plants and establishing
there colonies differing in many respects from the parent stock; from
these secondary hosts there is a return migration to the original species
of plant. Again, the migrations may be restricted to different parts of
the same plant, from the leaves or branches to the roots, for example.
Most aphides are readily controlled by means of insecticides, such as
nicotine-sulphate, or kerosene-emulsion. They are also very often held
in check by natural enemies, such as aphis lions, hover-flies, ladybirds,
and numerous forms of hymenoptera. The following species are some
of the commoner aphides met with in Xew Zealand : —

BLACK PEACH — APHIS (Aphis persico'-riiger). — From early spring,
even before the foliage develops, this aphis may be found heavily
infesting the young, succulent shoots of peach; it also occurs on cherry,
plum and nectarine. The adult insects are black and the immature
stages pale reddish-brown, dull brown, or lemon-yellow. During the
winter the insect lies underground about the roots of the host plant, and
thence migrates to the young growth in spring. At first only wingless
forms are seen, but as the season advances the winged migratory aphides
develop; at that time the foliage is so severely attacked that it becomes
crumpled and functionless (Fig. 9, 1), while the developing fruit is
distorted and rendered useless. The heat of the late summer destroys
the aphides still on the foliage, but sufficient numbers descend under-
ground for protection, where they live over winter.

GKEKX PFACH — APHIS (Rhophalosiphum persicce). - - This aphid
occurs on a wide range of plants, including the pea.ch, and, as a rule, is
most abundant during summer and autumn; as the name implies, the
general colour is green, though some individuals are reddish or brownish-
yello'W; the wingless forms have black-tipped "cornicles," and on the
abdomen of the winged insects are dark markings.

BLACK CHERRY — APHIS cm FLY (Myzus cerasi). — This aphid has now
a world-wide distribution. In Xew Zealand it has been found on
cherry and plum, though in other countries its hosts include peaches,
red and black' currants, and cruciferous plants, such as common mustard,
shepherd's purse, etc. This species exudes copious honey-dew, upon
which sooty mould develops, thus rendering fruit unfit for use. The
principal injury, however, is due to the destruction of shoots and leaves,
the latter frequently curling up when the insect clusters in dense
colonies upon the infested plant. The complete life-cycle has not been
followed under Xew Zealand conditions, but the shiny black eggs occur

44

0 A IM ) K X P K S T S 1 N X E W Z E A L A X D

on the bark and buds of cherry trees during the winter. In spring the
eggs hatch, and the insects, rapidly . i epiodueing. attack the young snoots
and leavo^. Observers in other- countries have noted that there is a
summer migration of winged females to cruciferous plants, where
Colonies are established, and whence there is a return migration during
the autumn to the original host. The wingless females are black, with
part of the legs yellow, while the vonng individuals are- pale in colour;
the winged, females have a. green jib'b'.m* n. from which aris,> the black
''honev-tuhes."1 Since all ihe ovi-i-whitei ing eggs have hatched bv the
time the buds open, the insect can be then controlled by applications of
nicotine-sulphate.

CABBAGE AIMII^ (JZreyicwyiie brftssizcr).; - - rl"he cabbage aphis, or
cabbage green I'y. is widely distril)iite«l throughout I1'" vrorld, and has
become a sei f in Ne\\ Zealand, can-ing < on.-idviab'c damage to

cniciferc; infests ta.pe. turnip, cabltage. l>ius<els sprout-s,

cauliflower, a^ \\ell as related weeds, Mich as wild mustard, shepherd's

FIG. 9.

(1) IVa^'i loaves attacked by mack IVacli apbis. (2) Colony of Oab'.viv.c ip'iis on leaf.
(8) Stem of insignis pine attacked hy Chennes. (4) Grape Phylloxe-x and ;;alis on
vine roots. (5) (irupe l'1-.ylloxeia s>'alis on vine leaf. «;> Woolly ap'ii^ on apple twig.
(7) (Jails of Poplar a plus. (Figs. 1, 2 and (i by W. C. Da vies : FU. 4. a!t«r U.S. Dept.
Agric. ; Fi,-. 5. after N.Z. Dept. Acrrii-.)

45

GARDEN PESTS IN NEW ZEALAND

purse and watercress. Most damage is done during dry seasons, when
the plants succumb more readily to attack; if the insects are numerous,
they cause the leaves to curl, and give a greyish appearance to infested
plants, which may become flaccid and sticky from the copious honey-dew
of the insect. The wingless forms are bluish in colour and coated with
a greyish powder, but the winged females have the head and thorax black
and the abdomen greenish (Fig. 9, 2). In New Zealand all stages may
be found throughout the year on winter crucifers or on weeds, though
reproduction is retarded during the winter; in the spring the winged
females fly to young crops. In very cold climates eggs are laid in the
autumn, and these survive the winter. The cabbage aphis is attacked
by a number of parasites, and usually the brownish empty shells of a
large number that have been destroyed by a small parasite are to be
found at any time; other important enemies are the hover-flies, the
eleven-spotted ladybird beetle, and the Tasmanian aphis lion. The insect
can be controlled by spraying with nicotine-sulphate to which soap has"
been added.

PIXE TREE CHERMES (Chermes pini). — This is a widely-distributed
species, ocurring upon both Austrian and insignis pine in Xew Zealand.
The insect lives in colonies upon the cones, twigs and branches, as well
as around the bases of the needles; each aphis exudes a woolly covering,
which forms conspicuous white masses when the trees are heavily infested
(Fig. 9, 3). Young trees seem to be the more subject to infestation,
from which they may recover as they grow, but some damage is caused
by the insect by a weakening of the trees, especially where grown in
unsuitable localities. It is frequently noticed that individual trees in
a plantation are heavily infested, while adjacent trees of the same
species are not. The wingless form of the insect, covered by its mat of
white threads, is brownish in colour and ornamented with numerous
dark spots; there are no '^honey-tubes" on the abdomen. The life-cycle
of this insect becomes complicated, when it develops on two types of
conifers; in the latter case the primary host is a species of spruce upon
which the insect forms galls, and the secondary host may be larch,
Douglas fir or pine, upon which gall formation is unusual. So far as is
known, only the pine-infesting f orm of the aphis k occurs in New
Zealand.

GRAPE PHYLLOXERA (Phylloxera vastatrix). - This destructive
aphis, sometimes called the grape louse, is a native of North America,
where it normally infests grape vines. It was accidentally introduced
into the grape-growing districts of France, where it became very
destructive. It later made its appearance in New Zealand. The insect
infests both the leaves and roots of grape vines, the root-feeding stages
being the most destructive, in consequence of which vines are now grown
on resistant root stocks. The leaf-infesting stages of the insect cause
pocket-like galls to form, which open on the upper surface of the leaf
by a narrow aperture concealed under a tuft of delicate hairs (Fig. 9, 5).
In each gall the aphid matures and deposits several hundreds of eggs,
from which wingless females hatch ; these wander to other leaves, and
each insect forms a new gall for itself. Several generations develop
thus, but later many of the offspring migrate underground and join the
root-infesting colonies. The irritation set up by the latter causes yellow

46

G A R D E N P E S T S I N N E W ZEAL A N D

flabby nodules to develop on the roots (Fig. 9, 4). These nodules, or
galls, later decay. The root-feeding aphides are wingless, and reproduce
by means of eggs' for several generations. Although they may go on
developing thus for many years, it usually happens that, toward autumn,
some of the insects transform to winged females, which fly to other
vines or are carried thence by the wind. There each female feeds on
the lower leaf surface, and deposits two kinds of eggs, some larger and
some smaller ; from the larger develop wingless females, and from the
smaller wingless males, which are unable to feed. After fertilisation,
each of these females deposits a single egg upon the older bark of the
vine ; such eggs do not hatch until the spring, when they give rise to the
wingless females that start the galls on the leaves. Control depends on
the use of phylloxera-resistant stocks, since it is from the root colonies
of the aphis that the foliage is re-infested in the spring. An important
feature is to prevent the scion from sending down roots where the union
of the scion and root stock is clo'Se to the soil ; if such scion roots form,
they should be cut away and the soil removed from the union.

ROSE AIM i is ( Nacroxi])lnun rvxfv). — The rose aphis is perhaps one
of the best-known insects of the garden, mainly owing to its prevalence
upon the young growth of all kinds of roses ; it sometimes occurs on
apple, tomato and rhododendrons. In a colony some of the insects are
pink, and others bright green, though in the winged forms the head.,
antenna1, thorax, a row of spots on each side of the abdomen, and the
"honey-tubes" are black ; in both winged and wingless forms the eyes are
red. In the case of severe infestations, plant growth is retarded and
the leaves and flowers become distorted. Control can be effected by
applications of nicotine-sulphate, kerosene, or soap solution.

APPLE WOOLLY APHIS (Eriosoma lanigemm). - - Although fre-
quently called "American Blight," the apple woolly aphis is probably a
native of Europe. It occurs throughout Xew Zealand, and was' a very
serious pest until controlled by the Aphelinus parasite. The presence
of this insect is made apparent by the characteristic white woolly patches
(Fig. 9, 6) which appear upon the apple trees, due to the woollv material
secreted by the aphid. Another feature is that the part of the tree
attacked, even after the insects have disappeared, is disfigured by gnarled
swellings, due to abnormal thickening of the inner bark. This species
also infests apple tree roots, which become similarly malformed. How-
ever, root infestation has been overcome by using root stocks, such as
Northern Spy, that are immune. The individuals comprising a colony
of woolly aphis are variously coloured, yellow, green and red pre-
dominating; a considerable amount of honey-dew is secreted. This
species has been found to migrate to the foliage of the elm and mountain
ash, but in Xew Zealand the elm-infesting form has not been found to
occur. The insect becomes active in spring, and rapidly increases
until the autumn. Under favourable climatic conditions, winged
females develop and produce males and females, the latter laying eggs.
The woolly aphis is preyed upon by the nine-spotted ladybird, but, as
this beetle -is itself the victim of another insect, its utility is t>Teatly
minimised. The most important check to the aphis is the Aphelinus
parasite (Aphelinus mall), the influence of which has been spectacular
under Xew Zealand conditions.

47

GARDEN PESTS IN NEW ZEALAND

PLUM APHIS (Rliopliwlosiplium nymphcece). — This insect is some-
times very common during spring upon the shoots and leaves of plum
in New Zealand; in other countries it has been found to migrate to and
infest the flowers and leaves of water lilies. The insects assume various
shades of green, the winged females having the head, thorax, and legs
blackish; the "honey-tubes" vary in colour, and may be reddish, blackish
or yellowish.

POPLAR GALL APHIS (Pempliiyux puptdi-im^versus). — Fpon the
leaf stems of poplar trees in many parts of New Zealand sac-like
growths (Fig. 9, 7), measuring anything from half an inch to one inch
in length, may be found. These are the galls formed by the Xorth
American poplar gall aphis. In each gall are colonies of the aphis sur-
rounded by a mass of flocculent secretion. The walls of the gall are
thick and tough, with the outer surface wrinkled, while at the end,
toward one side, is a slit-like, or sometimes circular, opening surrounded
by a thickened rim, presenting much the same appearance as the mouth
of a sack gathered together and tied. For the most part, these insects
are wingless females only, but during the summer, and particularly
toward the end of autumn, winged females develop and migrate to
cruciferous plants, such as cabbage, rape, mustard and turnips, or weeds
allied to these cultivated forms, upon the roots of which they establish
colonies surrounded by a woolly secretion. In spring a return migration
to the poplar takes place, and galls are again established.

Leaf-hoppers.

Leaf-hoppers form a group of small, narrow-bodied, sap-sucking
insects; as the name implies, they infest the foliage of a variety of
plants, and when disturbed have the habit of suddenly leaping or
hopping to safety; the species present in Xew Zealand are usually of a
greenish or yellowish colour. The adult insect is winged (Fig. 8, K, L),
and the female lays her eggs in the plant tissues (H) ; from these eggs
the young wingless hoppers (I) hatch and attack the plant; as they
grow, wings develop (J), but until then the insect depends for loco-
motion upon its hopping powers.

The most outstanding species in Xew Zealand is the apple leaf-
hopper (Typhlocyba austmlis). This insect causes considerable damage
to apple trees unless controlled, which can lie effected by spraying with
nicotine-sulphate against the young insects in the spring.

White-flies.

White-flies, or mealy-wings, are minute sap-sucking insects,
having the body and wings covered writh mealy wax. The female
(Fig. 8, P) lays her eggs, frequently in circular batches, upon foliage,
and the young insects (X) are active, but settle down and commence
feeding soon after hatching. Later the insects change to another form
(0), without legs and antennas, and so resemble scale insects to a certain
extent ; from the latter, however, they may be distinguished by the waxy
covering, bearing spine-like processes, and by being surrounded by a
distinct marginal area. An important species in Xew Zealand is the
greenhouse white-fly (Trialeurodes vapomriorum ) , against which fumi-
gation with calcium cyanide is the best as a check.

48

GARDEN PESTS IN NEW ZEALAND

Thrips.

The foliage of many plants is sometimes infested by very minute
black insects, known as thrips. ' A species commonly met with is
that found upon ripe peaches. Thrips are readily identified by the
structure of the wings (Fig. 8, 4), which are but narrow strips fringed
with long, rigid hairs. These insects, by puncturing the plant tissues
and sucking up the nutrient sap, very often are responsible for infecting
healthy plants with disease, such as mosaic.

According to the species of thrips, the female lays her eggs either
in the plant tissues or upon the surface. The young insects are wing-
less, but attack the plant in the same manner as does the adult; as
development proceeds, the insect transforms to a pupa, from which the
adult ultimately emerges. A characteristic symptom of thrips infesta-
tion is a silvering of the foliage, while the leaves are further rendered
unsightly by the minute specks of hardened excreta ejected by the insects.
Many thrips pass their, whole development upon the host plants, while
others pass part of their lives underground. One' of the commonest
species met with under glass and out of doors is the greenhouse thrips
(Heliothrips liasmorrUoidalis). Thrips are readily controlled by means
of nicotine-sulphate.

49

GARDEN PESTS IN NEW ZEALAND

CHAPTER VII.

Leaf-Feeding Insects.

EIAF-FEEDING INSECTS have their mouth-parts developed for
the biting off and mastication of their food; such insects are, in
general, earwigs, crickets and grasshoppers, the caterpillars of moths
and butterflies, beetles and their grubs, and the grubs of saw-flies. Such
insects vary, not only in their period of activity, some feeding at night,
others during the day, but also in the manner under which they set
about it. Many feed exposed upon the surface of the plant, while others
require protection, such as is afforded by the webbing together of leaves.
Some feed upon the leaf epidermis only; some eat holes in the leaf-
surface, or gnaw irregular notches from the leaf -edge ; while the grosser
feeders completely devour the whole.

Earwigs.

In many parts of New Zealand the European earwig (Forficula
auricularia) causes considerable damage in gardens, while in Central
Otago it sometimes ruins the stone fruits. During the winter this insect
lies underground, where the female will be found with her cluster of
eggs. In the spring these eggs hatch, and the small whitish young
earwigs (Fig. 4, 2) emerge from the ground to feed largely upon the
pollen and pistils of flowers. At that time the insects and the injury
-they do are not very noticeable, but as the earwigs grow in size they
become conspicuous and extend their depredations to the foliage of
plants and to fruit. Earwigs are nocturnal in their habits, and during
the day take shelter among fallen leaves, under stones, sacking, or
boards, etc., lying on the ground, and may even burrow into the soil
itself.

In the control of the earwig, a great deal can be done by what may
be called clean gardening — that is, the removal of all places likely to
shelter the insect above ground during the day. Another important
means is systematic trapping, one of the simplest methods being to place
crumpled newspapers on the ground at nightfall, in which many of the
insects will seek shelter, the papers being collected and burned next day.
But the best method is the use of the following poison bait: — With 121b.
of bran mix 6 quarts of water, to which has been added 5oz. of glycerine
and 6oz. of sodium fluoride; to this mash add 4lb. of treacle, taking
care to thoroughly mix the whole.

This bait is spread at nightfall in places frequented by earwigs, and
should be repeated regularly, especially after wet weather. It is obvious,
if satisfactory results are to be secured, that there should be a co-opera-
tive campaign organised among the residents of an earwig-infected
district.

50

GARDEN PESTS IX NEW ZEALAND

Crickets and Grasshoppers.

Fortunately, neither crickets nor grasshoppers (Fig 10 1 and 2)
are a serious menace to the New Zealand horticulturist though at times
especially in the warmer parts of the country, crickets may do some'
extensive damage. The control of these pests is a difficult matter since
they are mobile insects, and breed in places outside the boundaries of
the horticulturist s activities. .Some benefits can be secured, however
by thorough cultivation which breaks up the egg-masses which are
placed in the ground. In the case of serious outbreaks, the use of a
oisoned bait would have to be resorted to, and the following is recom-
mended from the several recipes in use :— With 251b. of bran mix 3 or 4
gallons of water in order to make a thin mash; to this, add 2 quarts of
molasses and lib. of Paris green, thoroughly mixing the whole If
crickets alone are to be dealt with, then use a little more of the Paris
I his mash is spread on the ground invaded by the insects.

Caterpillars.

Of the leaf-feeding insects, the caterpillars of moths are the most
commonly met with, there being a considerable number of destructive
species. Caterpillars (Fig. 10, 3) can be readily distinguished by their
structure from the grubs of other insects. They resemble shortearth-

. ea-

of T F+i Pe' and m11havin^ th* bodJ Divided into several segments,

o + 11 ,

m Th are,USrUJ ^teei!; but here the ^semblance to worms
tops. I here is a distinct head— the first segment-provided with jaws,

ft™ ?Yn?eJ SIde £leach of the next thre* segments, or thorax, i
a pair of short feet The remaining segments comprise the abdomen,
and possess sucker-like feet, varying in number according to the kind
of caterpillar; in some forms there may be as many as five pairs of such
teet, in some three pairs, and in others two, but in all the pair on the
terminal segment persists Many caterpillars are more or less hairy, and

• The following are amongst the

i ^* is a common sight to see small greenish cater-

pjllars sheltering between two or more leaves of plants that have been
tied together by the silken threads spun by the caterpillars; protected
thus, the insects feed more or less in security. These caterpillars belong
to several species of the tortricid moths, which are themselves compara-
tively small and drab in colour. Of these species, the most abundant
one comprising over 84 per cent, of the leaf-roller population, is the
Australian apple-leaf roller (Tortrix postvittana); the caterpillars of
3 insect by no means confine their attacks to the apple, but feed
equally well upon pear, orange, grape, rose, insignis pine, oak, pelar-
•omums etc Apart from attacking the foliage, the caterpillars fre-
quently tie a leaf to the surface of apple and stone fruits, and feed upon
the skin of the latter, causing a blemish.

The apple-leaf roller passes the winter in the caterpillar stage
between two leaves. In the spring these caterpillars transform to pup*
which give rise to moths from the end of August to about the end of
'ctober; there are at least two broods of caterpillars during the vear
but the limits of these broods are not clearly defined. The caterpillars
are attacked by several species of parasites.

GARDEN PESTS IN NEW ZEALAND

Leaf-rollers are easily controlled by the arsenical sprays used against
codlin moth, but these sprays must be continued into the late summer
after their need against codlin moth is past.

DIAMOND-BACKED MOTH (Plutella maculipennis). - - The cater-
pillars of this moth (Fig. 10, 4) are commonly found attacking the
leaves of cabbages, rape and other cruciferous crops and weeds. These
caterpillars are small and greenish, and, if disturbed, suddenly drop
suspended by a silken thread attached to the plant. The damage they
do is very often extensive, considerable areas of the foliage being
devoured. When fully developed, each caterpillar spins a silken cocoon
on the under side of the leaf, and there transforms to the pupae, from
which a moth eventually emerges. The insect is small, narrow, and has
a light-coloured, diamond-shaped marking along the back. The moth is
nocturnal, and shelters amongst the denser foliage during the day; it
emerges at night, and lays its eggs upon the leaves. The life-cycle from
eggs to adult occupies some 36 days, more or less, according to the
season, and there may be six or seven generations during the year.

In control, an important point to note is that the diamond-backed
moth breeds upon cruciferous weeds — watercress, shepherd's purse, and
hedge-mustard — as well as on the old plants of a crop left in the
ground; it is from such places that infestation of future crops arises,
and the clearing up of such breeding places should be given close atten-
tion. Under garden conditions, control can be secured by spraying the
plants with arsenate of lead (to which a spreader must be added in the
case of cabbage), which should be done especially when the plants are
young.

KOWHAI MOTH (Mecyna maorialis). — The caterpillar of this native
moth sometimes becomes epidemic, when it does considerable damage
to kowhai, broom, lupins, and sometimes clover. The caterpillar, which
measures about an inch when mature, is of a greenish colour, having
rows of black tubercles with white centres along the sides, and a double
TOW of white spots along the back ; from the black tubercles black bristle-
like hairs arise. The caterpillar spins a silken cocoon, in which it
pupates. The moth is comparatively small, the fore wings being
yellowish-brown with darker markings, and the hind wings orange-yellow
with a blackish border. There are at least two broods of caterpillars
annually: the first in the spring, and the second during autumn.
Arsenate of lead will give effective control on garden legumes.

CUT-WOK MS. — This term is applied to the caterpillars of a number
of night-flying noctuid moths; these caterpillars are smooth-bodied and
rather worm-like, in some cases measuring from one and a-half to two
inches in length when full grown. They feed at night, and their method
of attack is characteristic in that they nip off young plants close' to the
ground (Fig. 10, 5), so that the latter fall over, when they are devoured
by the caterpillars; this habit has given rise to the name "cut-worms."
I)uring the day the cut-worms are to be found curled up in the ground
close to the plants they have been attacking. The moths of these cater-
pillars are rather stout-bodied, and measure about three-quarters of an
inch long. One of the commonest species is the cosmopolitan greasy-
cut-worm (Agrotis ypsilon).

52

GARDEN PESTS IN NEW ZEALAND

FIG. 10.

(1) Cricket. (2) Grasshopper. (3) Caterpillar. (4) Diamond-backed Moth — a, adult
moth; b, egg; c, larva; d, pupa. (5) Cut-worm lying by damaged plant. (6) Tomato-
worm Caterpillar — a, adult; b, larva. (7) Cabbage White Butterfly — a, adult; b. egg;
c, larva ; d, pupa. (8) Larva case of Bag-moth.

53

GARDEN PESTS IN NEW ZEALAND

Though cut-worms are active throughout the growing period of
plants, most damage is done to young and tender plants at the time of
establishment, and this is particularly noticeable in the spring. When
plants are grown isolated in rows, and the area is not too large, complete
protection from cut- worms can be secured by enclosing each plant in a
tin collar pushed into the ground and projecting a few inches from the
surface ; these collars are removed when the plant is well established.
In. localities where cut-worms are very troublesome it is advisable to
reduce their numbers by means of a poison bait made as follows: — 501b.
of bran and lib. of Paris green are thoroughly mixed in a dry state ;
when this is done, and just before being used, the bran is moistened
with water, sweetened with molasses, until the bait reaches a crumbly,
but not saturated, condition. This bait may be broadcast over the
infected area or laid around each plant as a barrier. This bait must be
applied every few days until the plants have reached a stage when they
are able to withstand cut-worm attack.

A great deal can be done to check cut-worms by removing dense
growths of weeds and rough herbage growing in unused parts of the
garden; in such places the insects breed, and are a source of infestation.
Another point to consider is that thorough cultivation will destroy many
pupae that are lying underground, and which would otherwise give rise
to another generation of moths.

"ARMY-WORMS." — These caterpillars are similar in their appear-
ance and general habits to the cut-worms,, but differ in their method of
attack. When present in numbers, they move through a. crop — especially
cereals — eating as they go, and leaving nothing but devastation in their
wake, much as does an invading army on the march. They are not of
so much interest to the horticulturist as to the farmer.

•TOMATO-WORM (Heliothis armigera). — This caterpillar (Fig. 10. 6)
is one of the most conspicuous caterpillars met with in the garden. Its
habit of boring into and eating the contents of tomatoes gives it the
name of "tomato-worm." It is a cosmopolitan insect, and is especially
destructive to flower buds and fruit, a wide range of plants being
attacked. The caterpillars vary in colour, some being greenish and
others brownish, with reddish, yellowish or white markings. The moth,
which belongs to the noctuid group, is on the wing both day and night,
mostly during the earlier part of the year; it is a stoutly-built insect,
measuring somewhat over half-an-inch long; its colour is a brownish-
orange, with oblique darker bands on the wings. As the insect passes
the winter and spring as a pupa in the ground, thorough cultivation will
help to destroy a considerable number. The use of arsenate of lead
sprays, however, is the most effective control for the caterpillars.

HAWK OR SPHINX MOTH (Sphinx convolvuli). — This conspicuous
insect and its caterpillars are most abundant in the Auckland province,
though found as far south as Christchurch. The caterpillars
feed on convolvulus, but do considerable damage to the foliage of the
kumara and sometimes tobacco. The caterpillar is the largest met with
in the garden; it is stout in form, and measures up to 3-J inches when
fully grown. It is to be recognised at once on account of the dark red,
horn-like process arising -from the end of the body. The caterpillar may
be of two colours — the one green, with diagonal yellow bars on the sides ;

54

GARDEN PESTS IN NEW ZEALAND

the other, brownish-yellow, with dark lines on the back and sides. From
about February to November the insect lies in the ground as a pupa.
The latter can be recognised by a curved process arising from the head
and lying along the body. The moth flies rapidly during the last and
earlier months of the year; it is a large, conspicuous insect, about 1-|-
inches long, with greyish-brown mottled wings, while the abdomen is
conspicuously barred with white, red and brown. Arsenate of lead
against the young caterpillars during November to February would act
as an efficient control.

CABBAGE WHITE BUTTERFLY (Pieris rapce). — This butterfly (Fig..
10, 7) is a recent importation, having been first noted at Napier in
1930. Since then it has spread with marvellous rapidity throughout
the North Island, and has appeared in the South Island, in the vicinity
of Timaru.

The caterpillars of this insect are particularly severe in their
attacks upon the foliage of cabbages and cauliflowers, though they also
feed upon many other related plants, such as lettuce and radish, besides
cruciferous weeds. The caterpillars of the white butterfly are not to be
confused with those of the diamond-backed moth, already described. The
full-grown white butterfly caterpillar is a conspicuous insect, and
measures up to an inch and a-quarter in length ; it is easily distinguished
by its leaf-green colour and velvet-like appearance, while down the
centre of the back is a narrow orange stripe, and on each side a
brownish line formed of little spots. The chrysalis measures about
three-quarters of an inch long, having a pointed process from the head,
and a keel-like ridge on its back, while the colour varies according to
the surroundings with which the chrysalis blends; it is not protected by
a cocoon of silk, and may be found upon the food plant or any other
support near by.

The butterfly itself is a very conspicuous insect, measuring about
two inches across the expanded wings. The female is of a yellowish-
white colour, with darker to blackish markings at the fore-angles of the
front wings, while there are two similar spots on the surface of the same
wings, and one on the hind pair. The male is whitish, with a dull
greyish-green or bluish hue, marked much as the female, except that
there is only a single spot on the surface of each wing.

^ The eggs (Fig. 10, 7b) are bottle-shaped, and stand erect upon the
leaf surface, where they are laid singly, and not in batches; they are
visible to the naked eye. The eggs hatch within a week after being laid.
There are several generations each year.

The cabbage butterfly can be controlled by the use of lead arsenate.
It has been found effective when planting out to first dip the seedlings
in lead arsenate at the rate of lib. in 50 gallons of water, to which
lib. of laundry soap is added as a spreader. During the growth of the
crop the same strength of arsenate and soap can be applied as a spray.

MAGPIE MOTH (Nyctemera annulate). - - One of the commonest
and most conspicuous day-flying insects of the garden and field is the
magpie moth. It is black in colour, relieved by .an orange-banded
abdomen and whitish spots on the wings, two on each of the front wings
and one on each hind one. Its black, hairy caterpillars, commonly

55

GARDEN PESTS IN NEW ZEALAND

called "woolly bears/' have narrow brick-red lines along the body, and
very often do some considerable damage to cinerarias; they also attack
weeds, such as ragwort and groundsel.

The small globular eggs are laid in clusters on the leaves of the
food plant. At first they are pale green, later becoming dark yellow,
and just before the young caterpillars emerge from them they change
to a leaden colour. When fully fed, the caterpillar seeks a sheltered
place (beneath stones, under, bark, etc.), and there spins a loose cocoon,
in which it transforms to the chrysalis; the latter becomes blackish or
brownish in colour, with yellow markings. There are several generations
during the year.

Cinerarias can be protected by spraying with lead arsenate, or,
better, by removing the caterpillars by hand and destroying them.

CABBAGE TREE MOTH (Venusia verriculata). — The foliage of the
cabbage tree is frequently holed on the surface and notched along the
edges — this is the work of the cabbage tree moth caterpillars. The
history of the insect is as follows : — The nocturnal moth measures about
an inch and a-half across the expanded wings, which are characteristic-
ally coloured by alternating chocolate-brown and yellowish-white lines
running from wing-tip to wing-tip across the body, so that the insect
merges into the general pattern and colour of a dead leaf, upon which
it usually rests. The eggs are green, and at first blend with the green
leaf, on which they are often laid in batches; when on dead leases they
become conspicuous. Later the eggs change colour to brown, and finally
red. The caterpillars congregate in the unopened foliage, and their
injury becomes apparent as the leaves open. The larvae transform to
chrysalids in silken cocoons, loosely spun in any suitable crevice upon
the trees. If it was necesary and practicable to protect ornamental
cabbage trees from the attacks of this insect, it could be done by
removing dead leaves from the crown and spraying with arsenate of lead
to which laundry soap had been added.

BAG MOTH (CEceticus omnivorus). — This is an insect that never
fails to attract attention on account of its cigar-shaped bags (Fig. 10. 8),
constructed by the larvae, and are to be found attached to a variety of
plants, upon the foliage of which the larvae feed, though they are not
serious pests. Each caterpillar spins its own tough silken bag, which
it never leaves, and to the outside of which it frequently attaches frag-
ments of leaves and twigs. Though the male is a normal moth, and
flies about (it is practically black, and densely haired, with translucent
smoky-black wings having an expanse of about an inch and a-quarter),
the female develops in an abnormal manner, and assumes a grub-like
form, never leaving the bag woven by its caterpillar.

If it should be found necessary, as sometimes happens, the only
satisfactory way of controlling the bag-moth is to remove by hand and
destroy.

Beetles.

Unlike the caterpillars of moths, there are very ,few beetles in New
Zealand that are, important leaf -feeders. Though few in numbers,
however, the outstanding ones are very destructive. The beetles them-
selves, as well as their larvae, according to the species, may attack

56

GARDEN PESTS IN NEW ZEALAND

foliage, but in other cases it is only the beetles that feed on foliage while
their larva? live underground on roots. The following species are
outstanding : —

COCKCHAFERS. — These are the adults of the grass grubs, and there
are several species, all native to Xew Zealand. The commonest and most
destructive one (Fig. 11, la) is the so-called brown beetle (Odontria
zealandica), misnamed the "turnip fly," which is on the wing for about
six weeks each year, during November and early December as a rule. It
swarms at dusk, creating a loud, droning sound, and is responsible for
widespread damage by defoliating garden plants and field crops, as well
as trees.

This beetle is easily identified. It is rather plump-bodied, brownish,
smooth, and measures about three-eighths of an inch long. Like all
beetles, the front wings are hard, and form a cover over the body when

FIG. 11.

(1) a, Brown-chafer-beetle; b, antenna of beetle, showing finger-like processes; c, larva

or grass grub. (2) Bronze beetle. (3) a, Gum-tree weevil ; b, egg capsule ; c, larva.

(4) Eucalyptus tortoise beetle. (5) a, Pear saw-fly; b, larva from the side;

c, larva from above. (6) Pear midge.

57

GARDEN PESTS IN NEW ZEALAND

closed; these hardened wings, or elytra, do not reach quite to the end
of the abdomen, the tip of which remains uncovered. Another definite
character is found in the antenna?, which terminate in finger-like
processes (Fig. 11, Ib). There are several species of cockchafers, to
which all these characteristics, except the colour, might be referred, but
none is so abundant as the species under review. There is one, however,
that is on the wing about the same time as, or a little earlier than, the
brown beetle. This species is somewhat larger, about half an inch long ;
it is sparsely clothed with hair, and the elytra are marked by broad
brown stripes, alternated with very narrow darker ones.

The brown beetle lays its spherical eggs in the ground, preferably
amongst the roots of grass, strawberries, etc. The grubs (Fig. 11, Ic)
are well known as grass grubs; they are whitish in colour, the swollen
terminal segment of the abdomen being very often darker. These grubs
are sometimes called "curl-grubs/' from their habit of lying doubled-up
when at rest or feeding in the ground. Towards September each year
the grubs of the brown beetle pupate prior to the beetles emerging in
November. These grubs wrill be referred to later under the chapter
dealing with subterranean insects.

In gardens and nurseries, the depredations of the beetles may be
lessened by spraying with lead arsenate, or by the use of sulphur smudges.
The use of smudges was developed very effectively as follows by Mr.
D. J. Buchanan, forest ranger at the Tapanui State Forest nurseries.
Sulphur is spread on strips of scrim, which are then rolled up and
placed in containers, such as old paint pots. The latter are set about
the nursery, and fired at evening, when they will burn throughout the
night, the fumes acting as a deterrent to the beetles. When only a few
plants are to be protected, such as bush roses, the beetles can be warded
off by allowing a hose to play over the plants throughout the night.

Another common cockchafer which is on the wing most of the
summer and autumn is the green manuka beetle (Pyr&nota f estiva)..
This insect is capable of causing considerable damage as a defoliator.
It is active both day and night. The general colour is bright green,
with a dark stripe down the middle of the back, though some specimens
are brown or coppery; the legs are orange-yellow, and the length of the
insect is a little over a quarter of an inch.

BRONZE BEETLE (Eucolaspis brunneus). — This insect (Fig. 11, 2}
is very often confused with the brown beetle, from which, however, it is
easily distinguished. It is active during the day, and attacks the foliage
and fruit of a great variety of plants, eating holes from leaves, so that
the latter appear as if they had been subjected to a charge of shot, or
devouring the epidermis from fruits and berries. This beetle is active
during November to January; it measures about one-sixteenth of an
inch long, is oval in outline, and varies in colour from yellowish, with
darker markings, to greenish or bronzy-black ; the antennae are compara-
tively long, and do not terminate in any unusual manner, as do those
of the cockchafers. A characteristic habit of the bronze beetle is to leap
off the plant if disturbed; this habit has been responsible for the group
to which this insect belongs being called "flea beetles." The bronze
beetle lays its eggs in the ground, where the larvae feed, though they are
not injurious in that stage. The beetles are to be controlled by the use
of lead arsenate.

58

GARDEN PESTS IN NEW ZEALAND

GUM TREE WEEVIL (Gonipterus scutellatus). — Both the adults and
larva? of this Australian weevil attack eucalyptus foliage, particularly
bluegum, in most parts of Xew Zealand, the adult weevils eating from
the leaf margin, as well as devouring tender shoots, while the larvae cut
elongated holes from the leaf surface.

The weevil (Fig. 11, 3a), which is of a tawny to brownish-black
colour, and clothed with yellowish-white and golden hairs, measures
from a quarter to one-third of an inch in length; it possesses a short
snout on the head. The eggs are yellowish, and are packed in a hard,
black capsule (Fig. 11, 3b), attached mainly to the surface of young
leaves. The larva? (Fig. 11, 3c) are legless, like those of all weevils,
and yellowish at first, when they are studded with small black dots, and
have a dark stripe along each side. Frequently these young larvae are
seen with a tail-like thread of blackish excrement projecting from the
posterior end. The plump, fully-developed grub is yellowish-green, with
a wrinkled skin, and is slug-like in general appearance. Pupation takes
place in the ground. This insect over-winters in the %dult stage, and
large numbers of the weevils are very often to be found beneath loose
bark on the tree trunks during the winter. Control depends upon the
use of an egg parasite which has been established in certain localities
of the Dominion. In the case of small ornamental trees, spraying with
lead arsenate* to which laundry soap has been added should be effective.

EUCALYPTUS TORTOISE BEETLE (Paropsis dHatatw). — This is another
Australian insect restricted so far to the East Coast districts of the
South Island, where it attacks eucalyptus foliage in company with the
weevil. The beetle (Fig. 11, 4) is tortoise-shaped, varies in colour from
reddish-yellow to reddish-brown, with darker markings on the back,
which is pitted by minute depressions, and has a length of from one-
third to half an inch. Like the weevil, this beetle passes the winter
beneath loose bark.

The eggs are conspicuous and cigar-shaped, being laid in clusters,
lying more or less on their sides, upon the foliage. The larva is rather
plump, and pointed posteriorly; it possesses legs, while at the tip of the
body is a sucker-like false foot. The general Colour is yellowish, varying
to a rosy-pink, there being a darker stripe down the back, while along
each side is a similar one above a row of black dots.

PEAR AND CHERRY SLUG, OR SAW-FLY (Calirad Umacina). -- The
slug-like larvae of this insect are very abundant upon hawthorn foliage,
and if not controlled do considerable damage to cherry, plum, pear, and
peach. These larvae (Fig. 11, ob) are very often called leeches, and
devour the epidermis, exposing the skeleton of the infested leaves; they
are slimy, of a dark green, though orange-coloured immediately after
a moult, and the head end is much enlarged, giving a clubbed shape to
the body, along the under side of which are several false legs. Pupation
takes place in the ground. The adult (Fig. 11, 5a) measures about a
quarter of an inch long, is rather thickly set, black in colour, and
possesses four transparent wings. The female deposits her eggs in the
tissue of the foliage by means of a saw-like ovipositor — hence the name
"saw-fly" — which is thrust through the lower epidermis of the leaf, when
a pocket is formed to receive the egg; each egg pocket forms a little
pimple on the upper surface. This insect is very easily controlled by
spraying foliage infested by the larvae with lead arsenate.

59

GARDEN PESTS IN NEW ZEALAND

Another saw-fly closely related to the foregoing species is the willow
saw-fly (Pontania proxima). This species has only recently appeared
in Xew Zealand, and its larvae live in galls, or swellings, on the foliage
of willows.

PEAR MIDGE (Perrisia pyri). — A serious pest of pear trees, which
for some years retarded the culture of pears, especially in the Auckland
district, is the pear midge. This is a minute, delicate, two-winged fly
(Fig. 11, 6), measuring about one-twenty-fifth of an inch long; it has
a blackish head and thorax, and an orange-red to brownish abdomen.
The female alights upon young leaves just burst from the bud; and,
while they are yet curled, lays her eggs between the folds. The larvae,
on hatching, live protected in the curled leaves, which they attack, and
which never unfold. The result is that the infested leaves eventually
turn black and brittle, and cease to function. The fully-developed
larvae drop to the ground, which they enter, and there pupate. The
midges become abundant in early spring, when the first young pear
foliage develops* and they keep on producing generation after genera-
tion until the autumn. The Avinter is passed in the larval stage under-
ground beneath the trees.

A parasite has been established against the pest, and is doing good
work. The insect can be reduced to a large extent by thorough winter
cultivation, especially beneath the trees. The insect's larvae, being pro-
tected within the curled-up leaves, are not reached by ordinary sprays,
but Dr. K. H. Makgill, of Henderson, secured some excellent results
on young trees by the use of nicotine.

OLEARIA GALL MIDGE (Cecidomyia olecvrice). --In many parts of
New Zealand where Olearia forsteri is grown as a hedge, it is very often
disfigured by the formation of malformations, or galls. These are caused
by a native midge known as the olearia gall midge. The midge itself
resembles the pear midge in structure, but is larger, measuring from
one-tenth to one-eighth of an inch long; it is conspicuous on account
of. its black thorax and blood-red abdomen. In early spring the midges
appear and lay their conspicuous masses of bright red eggs upon the
buds of the developing shoots. The larvae, on hatching, set up an irrita-
tion in the rapidly-developing tissues, causing the latter to swell and
become malformed into bunches of rosette-like galls. If the latter are
cut open, a number of the yellowish larvae trill be found, each in its
own compartment within the fleshy gall. There is only one brood of
adults each year. Control can be effected to a great extent by cutting
back and burning the badly-infested parts during winter, and by pruning
the young growth carrying the eggs in the spring. Spraying with
nicotine when the midges are active should also help to protect the
plants.

60

GARDEN PESTS IN NEW ZEALAND

CHAPTER VIII.

Boring and Underground Insects.

CODLIN MOTH (Cydia pomonellaj —The codliii moth caterpillar
burrows in developing apples and pears, and such "wormy" fruit
Is known to everybody.

The moth itself is seldom seen, since it lies concealed until after
nightfall, when it becomes active and lays its eggs. The insect (Fig.
12a) measures about three-quarters of an inch long, and is inconspicu-
ously, though beautifully, coloured; the fore wings, which cover the
"body when closed, are light grey, crossed by fine bands of a darker hue,
giving the appearance of watered-silk, while at the extremity of each
wing is a large bronze spot; the hind wings, seen only when expanded,
are of a light brown colour. The minute flat eggs are laid on the foliage
of leaves, on the fruit, or even on young bark; they appear at first as
glistening white specks, but, as development advances, a red ring
•develops, and finally a black spot just prior to the caterpillars hatching.

In some places the first larvae developing in the spring enter the
fruit by way of the calyx, but under New Zealand conditions it is more
usual for entry to be made by boring through the skin of the apple.
Having completed their development in the fruit, the caterpillars bore
their way out and spin their cocoons beneath the loose bark of the tree
trunks; in these cocoons pupation takes place, and from them the next
generation of moths develops.

Although in New Zealand there is usually only one generation
produced each year, three or even four develop in other countries. The
winter is passed by the larvae in their cocoons, and pupation takes place
just prior to the period when the moths emerge in the spring. As the
moths continue to emerge and lay their eggs for a period extending
from November to February, it is essential that regular applications of
arsenate of lead be made during that time in order to protect the fruit
from the larvae hatching from the eggs laid by the moths. In localities
where the spring larvae enter the calyx of the fruit, it is essential to
apply the first spray just after the petals fall, so that the poison may
lodge in the calyx before it closes. The removal of rough bark from
the trunks of both apple and pear trees is a help in controlling the insect.
Another method sometimes used is to band the tree trunks with strips
of scrim ; under these bands the larvae collect, and the former can be
later removed and destroyed with their tenants.

CURRANT CLEAR-WING BORER (Sesia tipuliformis). - - This de-
structive moth has been carried to and established in New Zealand, as
well as many other parts of the world. In currant gardens its larvae
cause the death of canes by eating out the pith. The moth (Fig. 12b)
is a very conspicuous and beautiful insect; the wings, w^hich expand

61

GARDEN PESTS IN NEW ZEALAND

to about three-quarters of an inch, are transparent and bordered with
golden-purple, a bar of the same colour crossing the surface of the fore
wings; the body (about half an inch long) is metallic-purple., the thorax
having a yellow stripe on each side, while the abdomen, barred with
golden bands, terminates in a fan-shaped tuft of purplish hairs.

The moths are active each year in the spring, when they lay their
brownish, globular eggs singly on the bark of the currant canes. The
resultant larvae bore into the stem and destroy the pith, passing the
winter in the damaged canes. In the following spring the larva? become
active once more and approach the surface, where pupation takes place
shortly before the moths emerge.

There is only one generation each year, and control lies in the
removal and burning of infested canes in late winter.

TOMATO STEM BORER (Gnorimoschema plcesiosema) . - Tomato
growers are frequently faced with the problem of the destruction of
tomato plants caused by the attacks of the larvae of the tomato stem
borer moth. This insect caused considerable damage for the first time
in Auckland some fourteen years ago, though it was known in other
parts of the country .as well.

The moth itself (Fig. 12c) is. a small one, measuring about a
quarter of an inch with the wings closed. In this position the insect
is wedge-shaped and conspicuous. Against the general greyish-brown
colour is a dark brownish area on each side. The eggs are laid on the
tomato leaves, in which the young caterpillars tunnel as they work
toward the leaf petioles, down which they burrow into the main stems.
In the damaged stems, pupation takes place. Under favourable condi-
tions, this insect may pass through at least three generations during
the season.

Control depends upon sanitation and the use of arsenate of lead
sprays. All infested stems, together with plants after the crop has been
removed, should be burned; as the insect is known to attack potato
plants and tubers, cafe should be taken to destroy all potato tops after
harvesting. Frequent applications of arsenate of lead are essential to
protect the tomato plants, especially during the earlier part of the season.

When on this subject, mention should be made of the potato-tuber
moth (Phthorimcea operculella) , which is somewhat similar to the
tomato-stem borer, both in appearance and habits. The larva of this
insect is best known from its habit of boring through potato-tubers;
these burrows become filled by a fungus after the larva? have vacated
them. The adult potato-tuber moth is a night-flyer, and lays its eggs
upon the leaves of the plants; the larva? burrow down the stems, and
may even reach the tuber below ground. When seed is not properly
buried, the moth will also lay its eggs in the "eyes," and so directly
infest the tuber; this danger applies also to potatoes in store or in bags.

In the control of the potato-tuber moth, the following points should
be noted : — Select only sound seed and cover well when planted. On
harvesting the crop, do not leave the bagged potatoes standing in the
field overnight, as they are exposed to infestation ; neither cover the open
bags with the potato-tops, as is commonly done, since this will attract
the moths. Destroy all tops immediately after harvesting. Dusting
potatoes in store with slaked lime will tend to act as a protection against
the moth.

G A R D E N PESTS I N N E W ZEALAND

FIGURE 12.

A — 1, Codlin moth ; 2, codlin larva in apple. B — 1, Currant clear-wing moth ; 2, clear-wing
moth larva in stem. C — 1, Tomato stem-borer moth ; 2, larva of moth ; 3, damaged
tomato stem. D — 1, A long-horn beetle ; 2, larva of long-horn beetle. E — 1, A leaf-
mining fly ; 2, leaf attacked by leaf -miner. F — 1, Subterranean grass-caterpillar moth ;
2, subterranean grass-caterpillar. G — 1, A click beetle ; 2, a wire-worm. H — 1, Larger
narcissus fly ; 2, smaller narcissus fly. K — 1, A subterranean spring-tail ; 2, a leaf-
eating spring-tail.

GARDEN PESTS IN NEW ZEALAND

KOUXD-HEADED BORERS. — Apple, almond, and citrus trees, together
with gooseberry and such ornamental and shelter trees as poplars,
tree-lucerne, and goat-willow, are sometimes damaged by round-headed
borers, which tunnel in the stems and branches. These borers (Fig. 12d)
are white in colour, narrow-bodied, and cylindrical, the segments being
usually well defined, and belong to a group of beetles known as long-
horned beetles, a group of insects to which the common hu-hu beetle
belongs. These beetles are narrow-bodied, and their antennae are com-
paratively long and conspicuous.

To control these pests, the only thing to do is to cut out and burn
the badly-infested parts. Where a borer is located (and this can be
frequently done by the presence of the powdered wood ejected from the
burrows)", the culprit may be killed by injecting into the tunnel some
carbon bisulphide and plugging up the openings with some clay or other
similar substance.

LEAF-MIXIXG FLIES. -- Very often the leaves of cineraria and
chrysanthemum are disfigured by the tortuous tunnellings of the
maggots of minute flies (Fig. 12e). The adult insects are two- winged,
and in structure resemble in many respects miniature houseflies. The
eggs are laid in the leaf tissues, in which the whole development of the
maggots and pupae takes place. The white maggots are small, legless
and headless. Spraying with black-leaf 40 would act as a deterrent to
the flies, while infested leaves should be removed and destroyed before
infestation becomes general.

GRASS GRUB (Odontria, zealandica). - - As explained in the pre-
ceding chapter, the grass grub is the larva of a native cockchafer beetle
(Fig. 11, 1). This grub, by feeding upon roots, causes extensive damage
to pastures and lawns, as well as to many garden plants, including straw-
berries. In the case of pasture and lawns, the presence of even a con-
siderable number of grass grubs is not detrimental unless they occur
concentrated in definite areas, when the damage is pronounced. With
garden plants, however, which are isolated when compared with the dense
root masses of grasses, the attacks of one or two grubs upon the roots
of a single plant may cause serious injury.

Grass grub damage to grasses is not merely due to attack upon the
roots. While feeding, the grubs swallow soil with the roots, rendering
the former spongy, and so disturb the normal circulation of moisture
about the grass roots. In the case of infested lawns, it is advantageous
to roll infested areas in order to pack the soil pulverised by the grubs,
and re-establish normal circulation of soil moisture. Another important
feature in grub control is to stimulate root development by means of
fertilisers. A recently-developed method of "grub-proofing" lawns is to
broadcast over every thousand square feet of turf to be treated one bushel
of screened sand or clean soil, in which 5lb. of lead arsenate powder
have been intimately mixed. This is said to remain effective for a period
of three years; but such fertilisers as nitrate of soda, superphosphate,
sulphate of potash, and potassium chloride should not be used on "grub-
proofed" turf, as they react witli the lead arsenate, and reduce its
effectiveness, though rotted manure or ammonia sulphate may be used.

The control of grass grubs damaging the roots of strawberry and
other plants is a difficult matter, though some benefit is to be derived

64

GARDEN PESTS IN NEW ZEALAND

by making holes about four inches deep with a stick in the soil near to
the infested plants and pouring in a little carbon bisulphide ; the holes
should be closed immediately. To protect strawberry beds, if they are
not too extensive, the most satisfactory method is to cover the plants
with scrim, stretched on frames, at dusk during November and early
December, when the beetles are flying; this will prevent the insects from
infesting the ground with their eggs. The use of sulphur smudges,
already referred to, is of great importance in this respect.

SnrruREAXi'AX GRASS CATERPILLARS. — These caterpillars are the
larvA? of native moths (Fig. 12, fl) belonging to the genus Porina,, and
when they become epidemic they cause much more extensive damage to
pasture and lawns than do the grass grubs. When full grown, the
greyish-black caterpillars (Fig. 12, f2) reach a length of about three
inches; they are soft-bodied and rather flaccid, and live in underground
burrows of varying depth. After dark, these caterpillars come to the
surface and devour the grass, eating it close to the ground, much soil
being swallowed by the larvae during the feeding. This soil is evacuated,
and resembles earthworm castings, but is mixed with silk spun by the
caterpillars; the emergence holes of the caterpillars, about the diameter
of a lead pencil, are conspicuous on the surface denuded of its covering
of grass. Pupation takes place underground, and when the moths
emerge the pupae first move to and project beyond the sin face of the
ground; these pupae are large and easily recognised by the wing-cases,
which are very short compared with the length of the body. The
moths are on the wing during spring and summer, the rest of the year
being spent in the larval stage. The moths are night-flyers, and are
amongst the largest species in New Zealand, their wings having an
expanse of frorn one to over two inches; they are heavy-bodied insects,
and vary considerably in colour. One of the commonest species is
brownish-yellow, or sometimes a smoky-grey, with a white streak bordered
with black on the fore wings; the hind wings may be pinkish.

The most satisfactory method of controlling the insect is to 'roll
infested lawns after dark, in order to crush the caterpillars whilst feed-
ing on the surface. Flooding an infested lawn with water will bring
most of the caterpillars to the surface, when they can be collected and
destroyed. Spraying, grass in spring and early summer with arsenate
of lead will tend to poison the immature caterpillars. There are at
least three species of insect parasites that attack these larva?, and there
is also a fungus which invades and destroys the whole body, taking the
shape of the insect; such fungus-infested caterpillars are commonly
called "vegetable caterpillars."

WIRKWORMS. — The roots of garden plants and germinating seeds
are often damaged by hard, wiry beetle grubs, reddish-brown or whitish
in colour, called "wire worms," so named from their resemblance to short
pieces of wire; they have three pairs of legs behind the head and a
sucker-like appendage on the last body-segment (Fig. 12, g2). These
grubs transform 'to narrow-bodied, brownish or blackish beetles, known
afritfelic'k-beetlestt ^Fig. 12, gl) from their habit, when overturned, of
righting themselves by a springing action, during which a distinct and
sharp clicking sou.nd- is made; ihe spring apparatus Consists of a spine,
the tip of which fits into a notch; on tjie under side of the thorax.

83

GARDEN PESTS IN NEW ZEALAND

Practically nothing is known as yet in regard to the biology of the
New Zealand click-beetles. They are extremely difficult to control, and
the larval stage covers a period of two or more years.

NARCISSUS FLIES. — There are two species of narcissus flies — the
larger (Merodon equestrix) and the smaller (Eumerus strigatus) both
occur in New Zealand. The larvae of these flies attack bulbs of various
kinds, the hosts of the larger fly being narcissus, hyacinth, tulip,
amaryllis, habranthus, vallota, galtonia, scylla, and leucojum ; and of
the smaller fly, narcissus, hyacinth, onion and shallot. These flies are
two-winged insects, the hind wings being wanting as such, arid belong
to a group called the syrphid, or hover flies.

The larger narcissus fly (Fig. 12, hi) resembles somewhat a
liumble-bee (which, however, has four wings) ; its stout and very hairy-
body measures about half an inch long. There is considerable variation
in colour, though black or brown predominates, with greyish or yellowish
hairs, and bands of the same colour; the bands, however, are absent in
some individuals.

During spring the insects fly about in the sun, and lay their eggs
at the leaf bases of the host plants, or on the exposed neck of bulbs, or
in the soil close by. The larvae, which are legless, yellowish grubs, enter
the bulb, and may completely destroy it. Infested bulbs may be
detected by an unnatural softness near the neck when pressed between
the fingers.

The smaller narcissus fly (Fig. 12, h2) is about half the length of
the larger, of a shiny black colour, with metallic reflections, and is not
clothed with hair. The eggs are laid in the ground, or at times upon
the plant itself. Several larvae of this fly may be found in the one
bulb; the larvae resemble those of the larger fly, but are smaller, and
have three small processes at the end of the body. The smaller narcissus
fly usually attacks the bulbs already damaged by some other agent,
though' it lias been known to infect sound bulbs.

Control of both these flies depends upon the destruction of infested
bulbs. Recent researches have shown that the flies themselves can be
poisoned in large numbers by a spray made of 4oz. of sodium arsenate,
lib. of crude glycerine, 21b. of white sugar, and four gallons of water;
this spray is applied during bright and warm weather.

SPRINGTAILS. — These are very minute, soft-bodied insects, which
are very active, and have a habit of springing with the agility of fleas.
There are several species, but two are of interest to the horticulturist.

One of these (Fig. 12, kl) is white in colour, narrow-bodied, and
lives underground, especially in damp places, where it damages ger-
minating seeds, or the roots of seedlings; even older herbaceous garden
plants are attacked. As a control, it is important to drain the soil in
damp locations and to dig in calcium cyanide about two weeks before
planting or sowing.

The second species is blackish and more or less spherical (Fig.
12, k2) ; at times it does considerable damage in the spring to the seed-
leaves of young plants as soon as they appear above ground. Spraying
small areas — e.g., of cucumbers, turnips, etc. — with black-leaf 40 would
help to protect the plants; as the eggs are laid in the ground, and as
these develop best under moist conditions, thorough cultivation prior
to sowing the crop is an important controlling factor.

66

GARDEN PESTS IN NEW ZEALAND

CHAPTER IX.

Miscellaneous Pests.

i

N" this chapter will be grouped for convenience mites, woodlice,
millepedes, slugs, snails, and eelworms.

Mites.

Mites, together with spiders and ticks, belong to a group of animals
distinct from the insects, from which, they differ in many respects; for
example, they possess four, and not three, pairs of legs in the adult state,
no head separated from the body as a movable, distinct region, while in
many cases, especially in mites and ticks, the abdomen and thorax are
continuous; in no case are wings developed.

Mites are of small size, some being microscopic, while others are
just discernable by the unaided eye. All species have the mouth-parts
developed for the purpose of feeding upon liquid food — e.g., blood (in
the case of those species that attack animals), decaying vegetable matter,
or the saps of plants. It is the last. — that is, those parasitic upon
plants — with which we are here concerned.

The life-history of mites presents some variability, and, though
there are fundamentally four stages of development, additional stages
have been developed by some species which tend to complicate the cycle.
The principal stages in development are as follows (Fig. 13, 1 — 5) :—
In practically all cases eggs are deposited, but few species being vivi-
parous. The larva, on hatching, possesses but six legs, and resembles
an insect in this respect; the larva then becomes quiescent, and after
moulting the eight-legged nymph appears. While in the nymphal state
the mite may undergo one or more moults, giving rise to additional
nymphal forms, that may complicate the life-history. From the final
moult of the nymph the adult mite emerges.

Perhaps the best-known mite in New Zealand is the European red
mite of apple trees (Paratetranychus pilosus), though it attacks a wide
range of plants apart from deciduous fruit trees, which it favours ; it
has been found on grape vine, raspberry, rose, hawthorn, citrus, etc.
This mite (Fig. 13, 6) occurs in Europe, Russia, British Isles, North
America, Australia, and New Zealand, and it causes considerable injury
to foliage, which assumes a brown appearance, owing to the tissues
drying up where they have been punctured by the mouth-parts of the
mite.

In the case of heavily-infested trees, the red eggs of this mite form
conspicuous patches on the bark during winter; these winter eggs are
laid from January onward till leaf-fall, and from them the young mites

67

GARDEN PESTS IX NEW ZEALAND

hatch in the spring, when the foliage is again attacked. The red mite
develops rapidly, and reaches the adult stage in about two weeks;
several generations are thus produced from spring to autumn, when the
eggs are laid upon the foliage.

The eggs (Fig. 13, ?') are very small, globular, and ribbed on the
surface; from the centre of each projects a hair-like stalk, somewhat
bent at the tip. The colour is bright red, changing to a deep orange.
The red mite lives freely upon the foliage, and does not produce a web,
as do related species; the adult female is bright red to dark brownish-red,
rather globular in shape, with comparatively stout legs and numerous
spine-like hairs on the back. Although the eggs of the European red
mite are exposed on bark and readily accessible to sprays during the
winter, no effective winter wash for their control is yet known ; the
most satisfactory method for checking the pest is to spray the active
stages of the mite with summer oil.

Another species of mite, having much the same habits and host
plants as the European red mite, is the brown mite (Bryobia, prcetiosm).
The eggs of this species are of a deep red, with a yellowish tinge in
many cases, but differ from those of the European red mite in the
absence of the polar-stalk and ribbed surface. The brown mites
(Fig. 13, 8) are of a dull red or greenish colour, lack the spine-like
hairs on the back, are decidedly flattened, and have the front pair of
legs abnormally long.

The common red spider (Tetranychus t&larius) is a species of mite
frequently met with on a wide range of plants too numerous to mention
here; in Xew Zealand it frequently injures violet, hop, currant, willow,
and many weeds. This mite is to be found in all stages practically all
the year round ; during the spring it is mostly found on weeds and such
cultivated plants as strawberry and violet. It is a web-spinning species.,
and the minute yellowish-red eggs are to be found scattered amonor a
fine web attached to the lower surface of leaves as a rule. The adult
mite (Fig. 13, 9) is very active; it is somewhat larger than the two
foregoing species, and of a yellowish-green colour, with a pair of con-
spicuous dark spots on the back. Though this mite can be held in check
by the application of lime-sulphur sprays, advantage should be taken of
thorough cultivation during the dormant season, since the mite hiber-
nates on weeds and among dead leaves and in the soil.

A mite very often met with by bulb growers is the bulb-mite
(Rhizoglyphus Jiyo&cinihi) , now found in most parts of the world.
Although this mite may possibly be able to attack practically all tuber?
or bulbs, it is commonly found infesting narcissus, hyacinth, tulip,
crocus, and Easter lily; it is especially abundant in bulbs with loose
scales, and has been found to be capable of attacking healthy tissue.
The life-history of this species is complicated at times by the develop-
ment of additional stages; one of these — the hypopus — is of particular
interest, as it shows more activity than the others, and attaches itself
to the bodies of insects, and is so transported. The mite develops from
egg to adult within a period of nine days under favourable conditions,
or as long as six weeks at other times. All stages of the bulb-mite
occur at the same time in infested bulbs, which become soft and rotten.
The adult mites (Fig. 13, 10) are smooth, yellowish- white, tinged with
pink, and have legs and mouth-parts reddish. Symptoms of their

68

GARDEN PESTS IN NEW ZEALAND

FIG. 13.

(1) Five stages in mite development: (1) Egg, (2) larva, (3) nymph, (4) older nymph,
(5) adult mite. (6) European red mite and (7) egg of same. (8) Brown mite.
(9) Common red spider. (10) Bulb mite. (11) Pear-leaf blister mite. (12) Common
woodlouse. (13) Garden millepede. (14) Garden slug. (15) Garden snail. (16) Bulb
eelworm. (17) and (18) Immature and mature beet eelworm. (19) and (20) Imma-
ture and mature root knot eelworm.

GARDEN PESTS IN NEW ZEALAND

presence are to be found in stunted growth and yellowing leaves, failure
of flower development, reddish spots on bulb scales, or a softening of
the bulbs. All seriously-infested bulbs should be destroyed, and the
ground where they were grown treated with calcium cyanide. For the
treatment of bulbs, they should be immersed for ten minutes in a two
per cent, solution of formalin heated to 122 deg. Fahr., or simply in
water at a temperature of 131 deg. Fahr.

Another group of mites of importance to the horticulturist is that
of the blister mites; they are so minute — measuring about a hundred-
and-fiftieth of an inch long — as to be invisible to the unaided eye.
Though so minute, however, their damage to foliage is characteristic
and conspicuous, so that their presence is easily detected. The most
important blister mite in New Zealand is the pear-leaf blister mite
(Eriopliyes pyri) ; it differs from the other mites described above in
having a long and cylindrical body, with only two pairs of legs crowded
at the head end, the elongate abdomen having the appearance of being
composed of innumerable segments (Fig. 13, 11). This mite lives in
colonies in blisters formed on the leaf, and sometimes on the leaf
petioles. In the spring the yellowish-green blisters will give the upper
surface of an infested leaf a spotted appearance, and as the season
advances these blisters become reddish and finally brown : in the case of
severe infestation, the blisters become so crowded as to merge into
masses.

During the winter the mites lie in the shelter of the bud scales ; as
soon as the foliage begins to develop in the spring the over- wintering
mites attack the leaves, each mite forming a blister, in which it produces
a colony of young. The offspring then migrate from the parent blister
and form blisters for themselves, and this goes on until autumn, when
the last generation of mites migrates for the winter to the shelter of the
bud scales.

Owing to the mites being protected within the leaf blisters, summer
•sprays are not effective as a means of control, which can be effected,
however, by spraying with lime-sulphur in the autumn, when the mites
are taking up their winter quarters, and again at bud movement in the
spring.

Woodlice.

Woodlice are so well known, that but little description is necessary
here. However, the following features are of interest. Thev belong
to the group of animals known as the Cnistacea, which also includes the
crabs; these animals breathe by means of gills, and are usually aquatic.
but some forms, such as the woodlice, have become adapted to a life on
land. In outline (Fig. 13, 12) the woodlice are more or less oval, with
the upper surfaces somewhat arched, and the lower flat; the body i*
divided into several segments, which may enable the animals to curl
up in the form of a pill. There is a distinct head, bearing a pair of
antennae and the mouth-parts, followed by seven large thoracic searments.
to each of which a pair of legs is attached; finally, the remaining six
segments are more or less crowded together, and constitute the abdomen.

Since woodlice are terrestrial gill-breathing animals, moisture is
essential for them, and it is in moist places that they abound. They
depend upon a mixed diet, being carnivorous, as well as herbivorous :

70

GARDEN PESTS IN NEW ZEALAND

though normally scavengers, their attacks upon seedlings and tender
parts of plants bring them into the ranks of important garden pests.

Woodlice hibernate under any convenient shelter; in the spring,
eggs are produced and carried by the female on the under side of the
body until the young woodlice hatch. During growth the cuticle or shell
is periodically cast, and a freshly-moulted woodlouse is white in colour.

The best method of control is garden sanitation, all rubbish likely
to harbour the woodlice being removed. Since they are nocturnal, the
woodlice can be trapped by means of moss laid on the ground ; the moss
in which the woodlice have taken shelter is collected during the day and
burned, or immersed in hot water to kill the animals, when it can be
used again. Some good results have been secured by means of sliced
potatoes dipped in arsenate of lead or Paris green; the potatoes are
placed within reach of the woodlice, which are attracted to and feed
upon the poisoned bait. Horse manure should not be used in seed beds
likely to be infested by woodlice.

Millepedes.

Millepedes are short, worm-like animals, with a fringe of numerous
short legs on each side (Fig. 13, 13), and have a characteristic habit of
curling up when disturbed. Though scavengers for the most part,
feeding upon decaying vegetation and on small organisms, they' may do
considerable damage to sprouting seeds, seedlings, and to tender plants;
they are particularly abundant in damp and warm soil, where there is
an abundance of rotting vegetable matter.

Having a keen sense of smell, millepedes are readily attracted to
poisoned bait in the form of sliced potato spread with Paris green :
another method is to place a piece of freshly-cut potato under an
inverted flower pot, to which the millepedes will be attracted, when
they can be collected and destroyed. A satisfactory control measure is
to treat infested soil with black-leaf 40, using one part in one thousand
parts of water.

Slugs and Snails.

Plants are very often greatly damaged by the depredations of slugs
and snails; frequently young plants are devoured as soon as they appear
above ground. These animals attack the plants after nightfall, and
during the day seek cover. Though slugs will shelter in the soil, they,
together with snails, will shelter in any convenient place, such as under
old boards, sacking, bricks and stones upon the ground, or under large
leaves or amongst rank herbage — indeed, in almost any place that affords
cover and moisture. Slugs and snails are especially active during we I-
weather, and at such times, owing to the overcast conditions, they will
continue their depredations in the daytime.

Though slugs are active throughout the year, and even during
winter when the temperature is favourable, snails pass the winter, as
well as hot, dry spells in summer, in a dormant state, often being found
together in sheltered positions where the conditions are dry.

Both slugs and snails copiously secrete a slimy substance, that
affords them protection against chemicals used for purposes of control.

71

GARDEN PESTS IN NEW ZEALAND

In the case of the slug (Fig. 13, 1-t), the shell is small and incon-
spicuous, but the large spiral shell of the snail (Fig. 13, 15) affords
the animal adequate protection, into which it withdraws itself in times
of danger. Both slugs and snails reproduce by means of eggs ; these are
white, spherical and opaque, and are deposited in the soil or under
decaying vegetation.

One of the best means of control is to dust the plants with powdered
tobacco. Another method is to treat infested plants with soot or lime,
but this must be done at night, and the material used must 'come into
actual contact with the pests. An effective poison bait, but one that
requires to be carefully handled, owing to its poisonous nature, is a mash
made of 61b. of bran mixed with lib. of arsenate of lead and an equal
weight of treacle; this is made into a stiff paste, water being added if
necessary. Lumps of this mash are placed about the plants to be pro-
tected. As a barrier to prevent the inroads of slugs and snails, plants
may be surrounded by a belt of calcium cyanide; this would have to be
replaced each night, and the utmost care taken in handling, since the
substance and the gas evolved from it are highly poisonous ; out of doors,
however, the gas, being diluted with air, would not be very injurious as
long as one did not stand over the treated ground longer than was
necessary for laying the cyanide.

Apart from the above methods, the key to the control of slugs and
snails is "clean farming" — that is, the removal of all places, such as
rubbish and rank vegetation, where the animals will find shelter; the
compost heap is a favourite breeding place, and this should be turned
over at intervals and dressed with lime.

Eelworms.

Eelworms are minute, unsegmented worms, related to the parasitic
thread- worms of animals, and are abundant in soil and water; it is
usually the surface layers of the richer soils that are inhabited by them.
Of the long list of species, only a few are destructive to vegetation, but
these constitute one of the greatest problems of the horticulturist. It is
thought that the injury caused to plants by eelworms is toxic rather
than mechanical, and some plants apparently are capable of producing
anti-toxins, which neutralise the toxins of the eelworms ; such plants
possess an immunity. There are three important species in New
Zealand.

The so-called bulb-eelworm (AnguiUulina dipsaci) attacks more
than two hundred kinds of plants, but is of especial interest to the horti-
culturist on account of its attacks upon hyacinths, daffodil, narcissus,
and gladiolus, causing deformity and rotting of the tissues (Fig. 13, 16).
It has been found that this eelworm develops from egg to adult within
a period of between three and four weeks; the eggs are capable of lying
dormant in the soil for as long as seven years. Infested bulbs and cornis
should be treated by immersion for three hours in water heated to
110 deg. Fahr.

Potatoes are often damaged by the beet eelworm (Heterodera
schaclitii), which causes what is known as "potato sickness/' when the
growth is retarded, and wilting takes place; the root-system shows an
abnormal development of secondary or "hunger-roots." The eggs are

GARDEN PESTS IN NEW ZEALAND

retained in the body of the female, which forms a protective sack or
cyst (Fig. 13, 17 and 18), and in this state the eggs pass the winter in
the ground, where they are known to remain dormant for a period of
ten years; under favourable conditions in the spring, the larvae emerge
from the eggs and attack the rootlets of suitable host plants, entering
them at the extreme tip. Satisfactory methods of control have not yet
been developed under field conditions, but a four-year crop rotation
following potatoes is suggested; seed potatoes from infested ground
should not be used.

The roots of tomatoes are often found to be a mass of galls, due to
attack by the root-knot eelworm (Heterodem radicicola), which also
infests tobacco roots as well as other plants (Fig. 13, 19 and 20). All
stages of this species are to be found in the root galls; the female lays
her eggs in a gelatinous egg sack, which remains attached to the parent.
The larvae, on hatching, either remain within the parent gall or leave it
and enter the soil, where they seek out and attack the roots of another
plant. In tomato gardens steam sterilisation of the soil is the most
effective means of control.

73

GARDEN PESTS IN NEW ZEALAND

CHAPTER X.

Principles of Pest Control.

IN" dealing with the control of plant pests, the objective is to prevent
attacks, or, when the attacks have established, to check them as
much as possible. In the latter case the term "exterminate" is in too
f reqnent use ; it is not usually practicable to exterminate a pest, and the
best that can be done is to check or control it.

In the control of animal pests, it should be borne in mind that the
pests are usually associated with other factors inimical to plant life,
such as unthrifty plants, due to injury or malnutrition, and fungous
and bacterial diseases, any one of which might be either the primary or
secondary cause of plant injury.

Though at times one method may serve as a means of control,
generally it is a combination of methods that gives the most satisfactory
results, rendering the conditions favourable for the plant and unfavour-
able for the pests and diseases. The principles underlying control are : —

(a) Garden management.

(b) Use of chemicals.

(c) Influence of natural enemies.

(a) Garden Management.

All parts of plants, both above and below ground, are subject to
infestation by pests and diseases. Under garden conditions, cultivation
is intensive, and plants are grown year after year on the same ground
in surroundings much more sheltered and crowded than in the open
field. Sound garden management is therefore an important control
factor, and the following features are fundamental: —

CONDITION OF SOIL. — The vigour of plants is dependent on the soil,
which therefore must be kept in the right state; it must be well tilled,
and must contain the requisite nourishment and moisture available for
plant use, and as far as possible be free of an abnormal population of
root feeding pests, such as eelworms and the larvae of many insects.
Proper cultivation is therefore the important factor in bringing the soil
into .the state most favourable to plant life, as all inimical factors,
including pests, are reduced. Wherever practicable, as in glass-houses,
soil-inhabiting pests and diseases can be completely controlled by steam
sterilisation.

IMPORTATION OF PESTS. — One of the readiest methods of infesting
a garden is the importation of pests on plants, and every care should be
taken to secure only pest-free stock. In this respect, also, must be
mentioned the use of stable and barnyard manure, in which pests such
as insect larva?, woodlice and eelworms are introduced; artificial ferti-
lisers are therefore safer.

GARDEN PESTS IN NEW. ZEALAND

OVERCROWDING. — The tendency to overcrowd, especially in house-
hold gardens, is to be avoided ; a favourite habit is to plant something in
every available space. Under such conditions pests and diseases will
abound, and before attempting to spread over a large area, and so lessen
the effect of their depredations, they concentrate in mass formation
within the confines of the garden as long as the food supply lasts;
further, plants tend to be less vigorous and more susceptible to infesta-
tion under crowded than under more open conditions.

INJURY TO PLANTS. — Care should be taken not to injure plants with
garden tools during cultivation, and a clean cut should always be the
object in pruning. Mechanical injury opens the way for infestation by
diseases and some insects.

GARDEN SANITATION. — Clean gardening is an extremely important
control factor. In most gardens there are rank growths of grass and
weeds in out-of-the-way places, along boundaries, and bordering culti-
vated plots. Such growths, especially when the weeds .are related to the
garden plants, are always favourite breeding places for many pests that
move on to cultivated plants immediately they appear above ground.
If these growths are cut and burned in the winter, and the ground
thoroughly dug, many a spring infestation will be suppressed by the
control of hibernating pests; it is the control of spring infestations that
will save a great deal oi' trouble throughout the summer and autumn.

The compost heap, where garden refuse is dumped until sufficiently
rotted, may be a source of infestation; not only does it attract and
breed many destructive underground pests, but it may be infested with
the spores of diseases harboured by the plant refuse of which it is com-
posed; it is thus a ready means of reinfesting the soil. Diseased and
pest-infested refuse should be burned without delay, and only healthy
refuse used for the compost heap if not dug into the ground, where it
will rot.

CROP ROTATION. — Growing the one type of crop on the same piece
of ground for several seasons encourages the development of pests and
diseases; but by a rotation of different kinds of plants the continuity
of the conditions favourable for the pests and diseases is broken, and
the latter do not have the chance of becoming thoroughly established.

DISEASES SPREAD BY PESTS. — It should be borne in mind that the
fewer the animal pests, the less chance there is for diseases to spread.
It is now well known that many pests, though not necessarily epidemic
themselves, are carriers from plant to plant of certain destructive
fungous, bacterial and virus diseases.

CO-OPERATION. — In a locality of many gardens a co-operative spirit
is essential, since a single neglected garden in an otherwise well-
managed locality will be responsible for discounting the labours of the
neighbours.

(b) Use of Chemicals.

Chemicals are essential in the control of pests and diseases, and are
applied either in the form of sprays or dusts. The former method is
the more usual in this country, but where the water supply is poor dusts
tend to take the place of sprays. Chemicals used for horticultural
purposes are of two distinct kinds — those for the control of animal pests

75

GARDEN PESTS IN NEW ZEALAND

and those for- the control of diseases. The commercial horticulturist,
however, finds it necessary to apply both in the one spray or dust for
the dual purpose of controlling both pests and diseases. As the present
work is concerned with the pests, and not diseases, only those types of
chemicals for the control of the former will be referred to.

Sprays and dusts are of three kinds, and act upon pests accordingly :
they are either stomach poisons, or act externally on the animal by
actual contact and corrosion, or cause death by fumigation. The kind
used is governed by the feeding habits of the pest; if the latter is pos-
sessed of jaws (woodlice, caterpillars, beetles, etc.), and feeds by.
chewing the plant tissues, then a stomach poison is applied and is
swallowed with the food ; if the food is the nutrient sap of plants, and so
could not be poisoned, a spray acting by contact is used, as against such
animals as aphids (green fly), scale insects, etc., in which the mouth-
parts are not adapted for chewing, but for puncturing plant tissues to
feed on the sap, much the same as a mosquito punctures one's skin and
sucks the blood. Fnmigants can be used against both the chewing and
sucking pests, the fumes passing into the breathing system.

STOMACH POISONS. — The chief of these are arsenate of lead and
Paris green, though the latter has practically gone out of use. Arsenate
of lead is sold as a paste and as a powder, and is mixed with water to
form a spray, 31b. of paste, or 1-Jlb. of powder, to 100 gallons of water
being the proportions used. For garden purposes, smaller quantities
must be kept to this strength.

CONTACTS. - • The chemicals used in contact control are red oil,
kerosene and lime-sulphur, but all are also fumigants, lime-sulphur
being also a stomach poison to a limited extent, though best known as
a fungicide. Commercial red oils can be purchased ready for mixing
with water without the necessity of emulsification, and the strength at
which each brand should be used is given by the manufacturers. Though
red oils have mostly replaced kerosene emulsion, many horticulturists
still prefer the latter. It is prepared by dissolving 8oz. of soap in one
gallon of hot water, and then adding two gallons of kerosene, stirring
briskly until emulsification is complete. This is the stock emulsion, and
must be diluted before use, the strengths being one part to six of water
for use in the winter, and one part to fifteen of water for use in the
growing season. Commercial brands of concentrated lime-sulphur are
on the market, and the manufacturers' directions for their dilution
should be followed.

FUMIGANTS. - - The chief fumigants are black-leaf 40, carbon-
bisulphide and calcium cyanide.

Black-leaf 40, in which nicotine sulphate is the effective principle,
is the most useful fumigant on the market, and acts as a most effective
control for sap-sucking, and even some chewing pests. The strength at
which this fumigant is used is one part in 800 parts of water, and is
applied as a spray.

Carbon-bisulphide is a liquid, the gas evolved from it being an
effective fumigant. It is not used as a spray unless emulsified, its chief
use in horticulture being for the fumigation of the soil, glass-houses,
stored seeds and vegetables, and imported plants. It is very inflammable
and extremely volatile, especially under higher temperatures, the heavy
gas being highly explosive when mixed with air.

76

.GARDEN PESTS IN NEW ZEALAND

The amount of carbon-bisulphide to be used varies, according to
circumstances. For soil fumigation a special type of "gun" is on the
market "for injecting the bisulphide into the soil, but for ordinary garden
purposes it is sufficient to make holes in the ground with a stick, pour
in the fumigant, and close up the holes. When holes are made about
18in. apart, half an ounce of bisulphide to a hole is sufficient, the depth
of the hole varying according to the depth of the pest to be controlled.

For the fumigation of seeds, bulbs, potatoes, etc., an airtight
chamber is necessary. This is also of value in the control of pests of
potted plants. The dimensions of a chamber will vary acco<rding to the
demands made upon it. Carbon-bisulphide gas being heavy, the con-
tainers (shallow dishes) should be placed on a shelf near the top of the
chamber during fumigation. The proportion of fumigant to the air
space varies according to the plants and insects to be fumigated.

For lawn-infesting insects, carbon-bisulphide can also be used in an
emulsion as a spray prepared as follows : — Fifty grams of powdered
resin are gradually added to 135 cc. of a 7 per cent, solution of sodium
hydroxide, previously wanned; 450 cc. of hot water is now added, and
the whole agitated until the resin is completely dissolved, when 50 cc.
of oleic acid is also added. To prepare the emulsion, three parts of this
soap solution are thoroughly agitated with seven parts of carbon-
bisulphide until emulsification is complete, which can be gauged by the
creamy-white colour and viscosity. For use dilute in the proportions
of 18 pints of the emulsion with 50 gallons of water, applying by means
of a watering-can or spray-pump at the rate of one gallon to every square
foot of lawn.

Calcium cyanide, on being exposed to the atmosphere, gives off
hydrocyanic acid gas, the evolution of the gas being governed by tempera-
ture and humidity. Calcium cyanide has replaced the old method of
generating the gas by the action of sulphuric acid on potassium cyanide,
and is sold in the form of dusts or granules. In the use of this material
very great care is necessary, since the gas is highly poisonous, and also
scorching of the foliage of plants results if atmospheric conditions are
not considered carefully. With ordinary care, however, calcium cyanide
can be safely handled. It is extremely effective against all kinds of
pests, and can be used to fumigate soil, glass-houses, or as a dust on
plants in the open.

(c) Influence of Natural Enemies.

As stated in the first chapter, plants are to be looked upon as the
primary producers of life (since all animals are directly or indirectly
dependent upon them ) , and the animals as the consumers. Many of the
latter are destructive to crops grown by man, and become pests, but
others, fortunately, exist upon these pests, and are classed as beneficial
animals ; it is the purpose of this section to deal with the more important
of these from a horticultural viewpoint. In New Zealand such beneficial
animals are insects, birds, and the hedgehog.

Insects.

There is a wide range of insects that live at the expense of their
fellows, and without these plant production would be impossible, either
by Nature or by man. These so-called beneficial insects or parasites
are the greatest factor in maintaining within reasonable bounds the

77

GARDEN PESTS IN NEW ZEALAND

insects that destroy vegetation ; they are of much greater value in thife
respect than birds. In. recent times the utilising of beneficial insects as
a means of pest control has developed as one of the most important
branches of entomological research.

From a general viewpoint, the beneficial insects are to be found
mainly among the groups, including wasps, beetles, flies (two-winged
insects) and lace-wings. The following are some examples : —

Common examples of parasitic insects are the ichneumon wasps
(Fig. 14a), chalcid wasps (Fig. 14b), and ensign wasps, the first being
the most conspicuous, the others less so owing to the minute size of
many of them. A characteristic feature of these forms is the stalk-like
attachment of the abdomen to the thorax and the sting-like ovipositor of
the female, which may be of short or moderate length, sometimes pro-
jecting as a tail-like appendage beyond the end of the abdomen. Para-
sites deposit their eggs either upon or within the body of their victims
or hosts, which are eventually destroyed by the larvae hatching from the
parasites7 eggs. Destructive caterpillars and their pupa?, and also
aphides, are attacked by these wasp-like parasites, which in many cases
restrict their depredations to one or a limited number of host species,
while others are more general in their selection. Another group, the
predaceous wasps, should be mentioned here. These insects in the adult
state are hunters, and capture and paralyse by stinging such insects as
caterpillars and flies, as well as spiders, which are stored in nests or
cells for the nourishment of the predators' offspring.

Important natural enemies of aphides and young caterpillars are the
hover-flies, which can be easily recognised by their manner of flight.
They are two-winged insects (Fig. 14c), and when on the wing hang
motionless, as if suspended by some unseen means, to suddenly dart off
with marvellous rapidity, until they hang motionless as' before. These
flies lay their eggs upon the foliage of plants infested by aphids or
caterpillars, and from these eggs legless and headless larva? emerge
(Fig. 14d), and commence to search for and feed upon their victims.

Another important group of two-winged flies is the tachinids. They
are rather robust, usually very bristly (Fig. 14e) ; they vary in size from
that of a large blue-bottle to comparatively minute forms. The
tachinids lay their eggs either upon their hosts or on the food plants of
the latter, where they can be swallowed; some tachinids give birth to
living larvae, which crawl about in search of their victims.

Among the beneficial beetles are the well-known ladybirds ( Fig.
14f ) ; they are mostly oval in outline, dome-shaped above and flat below,
while many of them are spotted by yellow, red, or white in a char-
acteristic manner, though others are of one uniform colour. The eggs
are laid on plants infested by the aphides and scale insects upon which
the beetles and their larvae (Fig. 14g) feed. There are other kinds of
beetles of importance as predators, such as the common tiger-beetle, but
they are not especially selective in their types of victims.

A very valuable group of insects includes the lace-wings or aphis-
lions. The adult insects (Fig. 14h) carry the seemingly over-large
lace-veined wings roof -like over the small body; the larvae are alligator-
like (Fig .14i), and possess a pair of caliper-shaped jaws, by means of
which they capture their prey. The eggs are laid directly on plants or
are attached at the end of long stalks.

78

GARDEN PESTS IN NEW ZEALAND

Birds.

It is generally recognised that birds are a very important aid in
"keeping destructive insects in check, though it is well-known that a
.great deal of damage can be done by these animals. Without a
systematic study of the stomach contents of birds, it is not possible to
decide when a species is beneficial or injurious, and in Xew Zealand no
such study has been made ; practically all the information we have is
based on field observations, which are, unfortunately, influenced largely
by the outlook of the observer, and are thus misleading. Though some
species subsist for the most part on insects,, most land-birds have a mixed
diet of vegetable and animal food, but they specialise on an insect diet
when rearing their young and when moulting.

FIGURE 14.

(a) An ichneumon (natural size liin) ; (b) a chalcid (natural size l-25in) ; (c) a hover-
fly (natural size $in) ; (d) hoverfly larva (natural size £in) ; (e) a tachinid fly (natural
size |in) ; (f) a ladybird beetle (natural size &in) ; (g) ladybird larva (natural size iin) ;
(h) lacewing (natural size iin) ; (i) lacewing larva (natural size £in).

GARDEN PESTS IN NEW ZEALAND

Based on the nature of their diet, birds fall into three principal
groups: (1) those feeding almost solely upon seeds and fruits:

(2) insectivorous birds feeding on insects and other animals; and

(3) the omnivorous species feeding both on insects and vegetable
matter. The seed-feeding birds are a potential menace to the agricul-
turist, though in Xew Zealand the native species are fundamental to the
well-being of the native forests; the insectivorous birds are obviously
beneficial, though they devour both destructive and useful insects ; while
the omnivorous birds may be either useful or harmful, according to the
circumstances. It should be remembered that, no matter what the food
of the adult bird may be, most species give their young a diet of insects
or other animal matter. When it is realised that the weight of nestling
birds increases from one-fifth to one-half each day, requiring at times
more than half the weight of the nestling in food, one can better
visualise the enormous quantities of insects daily destroyed for this
purpose. Consider the common house sparrow, which is usually con-
demned : an analysis of the nestling diet has shown that it consisted of
40 per cent, grain and 60 per cent, insects and related forms, while that
of the adult comprised 75 per cent, grain and 25 per cent, insects, etc.

To summarise the situation, it may be said that, on the whole,
enormous numbers of insects are destroyed by birds each year, and,
unless allowed to become abnormally abundant, the benefit derived from
birds outweighs the damage they may cause.

Hedgehog.

The hedgehog was first introduced by the Canterbury Acclimatisa-
tion Society in 1870, and later by other societies and private individuals.
The animal is now very abundant in many parts of the Dominion.
Though condemned and destroyed by some people, who consider it a
menace to eggs, chickens and even vegetables, the hedgehog is really a
very useful animal, in that, being a night prowler itself, it destroys
numerous nocturnal pests, such as slugs and snails, earwigs, grass cater-
pillars and cut-worms.

The hedgehog, on the approach of winter, constructs a nest in some
suitable place, where it becomes torpid and hibernates. On the advent
of spring, it becomes active once more, and during summer produces a
litter of four young; a second litter is sometimes produced in the
autumn.

INDEX.

Acacia

Agrotis ypsilon

A Igw

Almond

Amaryllis

American blight

Amoebcc

Anguillullna dipsaci

Animal Kingdom, Divisions of
Aphelinus fuscipennis . . . . ^ .

Aphelinus mali

Aphelinus mytilaspidis

Aphides

Aphis-lion

Aph'is persicce-niger

Apple 34, 35, 37, 38, 40, 41, 47, 48,

Apple leaf-hopper

Apple leaf -roller

Apple mealy-bug

Apple mussel-scale

Apple red-mite

Apricot

Army-worms

Arsenate of lead

Asexual

Ash

Asparagus

Aspidiotus hederw

Aspidiotus perniciosus

Asterolecanium variolosum
Austrian pine

Bacteria

Bag-moth

Baker's mealy-bug

Beet eelworm

Beetles

Begonia

Beneficial insects

Birds ,

Blackberry

Blackbird

Black cherry-aphis

Black-currant

Black-leaf 40 . . .

Black peach-aphis

Black scale

Blister-mites

Blue-gum

Borers, round-headed

Breathing systems of insects . .
Breviooryne brassicce

Briar 4

Bronze beetle
Broods of insects

Page

. 32, 38 Broom

. . 52 Brown-beetle

14, 15 Brown-mite

35,38,64 Brussels sprouts ..

. . 66 Bryobia prwtiosa

. . 47 Bulb-eelworm

. . . 15 Bulb-mite

. . 72 Bulb or Narcissus flies
. .. 8

. . . 40 Cabbage

. . 47 Cabbage aphis

. 38, 40 Cabbage green-fly . .

. . 42 Cabbage- tree

. 28, 78 Cabbage-tree moth . .

. . 44 Cabbage-tree scales

61, 64, 67 Cabbage white butterfly

. . 48 Calcium cyanide

51 Cdliora limacina

. . . 34 Camellia

. 30, 37 Camellia scale

. . 57 Carbon-bisulphide

35, 36, 38 Caterpillars

. . 54 Caterpillars in lawns

. . 76 Cauliflower

. . 42 Oecidomyia olearice . .

. . . 38 Cereals

. . 36 Chalcid wasps

. . 40 Chemicals

. . 38 Chermes pini

. . . 37 Cherry

. . 46 Cherry-aphis, black

Cherry slug

. 14, 15 Chitin

. . 56 Chrysalis

. . 35 Chrysanthemum

. . 72 Chrysomphalus aurantii

. . 56 Chrysomphalus rossi

. . . 34 Cicada

77, 78 Cineraria

. . 79 Citrophilus mealy-bug

. 36,41 Citrus .. . '. ..

. . . 35 Click -beetles

. . . 44 Clover

. 36, 44 Coccids

. . 76 Coccus hesperidum

. . 44 Cockchafers

. . 40 Cockroach

. . 70 Cocoon

. . 59 Codlin moth

. . 64 Comstock's mealy-bug

. . 21 Contact sprays and dusts

. . 45 Convolvulus

.. 41 Coprosma ....

. . 58 Cornicles

. 22 Cottony-cushion scale

52

58
68
45
68
72
68
66

45, 48, 55
. .. 45
. . . 45
. . . 56
. .. 56
. .. 38
. .. 55
. ..76
. .. 59
36, 37, 40
. .. 37
. .. 76
. .. 51
. .. 65
. 45, 55
. ..60
. .. 54
. .. 78
. ..75
. .. 46
38, 44, 59
. .. 44
. .. 59
. .. 17
. .. 25
. .. 64
. .. 40
. .. 40
. .. 28
34, 56, 64

34

32, 35, 36, 40, 64, 67

. . 65

52

29

36

57

17,27

25

61

35

.. 76
.. 54
.. 40
.. 42
30,32

.. 24,

81

Page

Page

Crayfish

17

Crape- vine . . 34, 35, 36,

37,40,46,51,67

Crickets

.. .. 27,51

Grass caterpillars

.65

Crocus

68

Grasses

. . . . 64, 65

Crop rotation

75

Grass-grubs

. . . . 57, 64

Cruciferous crops

-45

Grasshopper

.. .. 17,51

Cryptolaemus ladybird

34

Greasy cut-worms

52

{Jrytolcemus montrouziefi

34

Green-fly of cabbage

45

Curl-grubs

58

Green-house thrips

49

Currant

. . 37, 38, 61, 68

Green-house white-fly

48

Currant clear-wing borer

61

Green manuka beetle

58

Cuticle

17

Green peach-aphis

44

Cut-worms

52

Groundsel

' . . . . 24, 56

Cydia pomonella

61

Grub-proofing lawns

. . • . . . . 64

Gum-tree scale

.. .. •.. 35

Daffodil

72

Gum-tree weevil

59

Development of insects . .

22

Diamond-backed moth

52

HabrantTws

.. .. ..66

Digestive system of insects
Douglas fir

21
. . . . 32, 46

Habrolepis dalmanni
Hawk moth

37
54

Dusts

75

Hawthorn

. . 37, 38, 59, 67

Earthworms

15

Hedgehog
Heliotlifips hcemorrhoidalis

80
23

Earwig
Easter lily

. . . . 27, 50
68

Hemispherical scale
Heterodera radicola

36
73

Eelworms

. . .. 8.72

Heterodera schaohtii

72

Eggs of insects

22

Hibernation

23

Elder

.. ;. ..35

Holly

. . . . 35, 36

Eleagnus . . ....

37

Honey-bee

19

Elm

. . . . 38. 47

Honey-dew

. . . . 29, 42

Elm-leaf aphis

. . . . 42. 47

Honey -tubes

42

Elytra

58

Hop

68

Ensign wasps

78

Horse chestnut

35

Eriococcus coriaceus

35

Hover -flies

. . . . 66, 78

Eriophyes pyri

70

Hyacinth

66, 68, 72

Eriosoma -lamgerum
Eucalypts
Eucalyptus tortoise beetle
Euoolaspis brunneus

47
. . . . 35, 59
59
58

Hydrangea
Hydrocyanic-acid gas
Hypopus

35

77
68

Eulecanium berberidis
Eulecanium corni
Eumerus strigatus . .
Euonymus
European earwig
European red-mite

37
36
66
35, 37. 40
50
67

Icerya purchasi
Ichneumon wasps
Importation of pests
Insects, proportion of
Insignis pine
Invertebrates

'32
78
74
7
. . . . 46, 51
7

Irig

35

Fantail

35

Ivy

35, 36, 40

Ferns

. . . . 34, 36

J

Fig
Flax, Xew Zealand

. . 34, 35, 36, 40
38

Japonica

36

Flea-beetles

58

Karaka

40

Forficula auricularia

50

Kerosene

76

Fruit lecanium scale

36

Kowhai

52

Fumigants

76

Kowhai moth

. . . . . . 52

Fungi

. . . . 14, 15

Kumara

54

Galls

42

Laee-wing

. . . . 34, 78

Galtonia

66

Ladybird beetles

78

Gladiolus

.. .-. ..72

Larch

46

Gnorimoschema pl&siosema

62

Larger narcissus fly

66

Goat-willow

64

Larva

24

Golden oak-scale

37

Laurel

. . . . 35, 36

Gonipterus scutellatus

59

Lawns

. . 64, 65

Gooseberry 7

35, 36, 37, 38, 64

Lead arsenate . . ....

76

Gorse :

32

Leaf -hoppers

.' 48

Grape louse

46

Leaf-mining flies

64

Grape phylloxera

46

Leaf -rollers

51

Leech

Page
. . . 59

Parthenogenetic
Passion vine
Pastures . . k

Page
.. ..42

. . . . 34
64, 65

Lemon

... 35 40

f.t pidosaphes ulmi . .
Lepisma saccharina
Lettuce

37

26
55

Peach 35,36,
Peach-aphis, 'black
Peach-aphis, green
Pear 34, 35,
41, 50,
Pear and cherry saw-fly
Pear and cherry slug
Pear-leaf blister mite
Pear-midge
Pelargonium
Pemphigus populi-transrersus .
Pepper-tree
Perrisia pyri
Persimmon
Phormium

38, 44, 48, 59
. . . . 44
. . . . 44
36, 37, 38, 40.
59,60,61.7(1
. . . . 59
. . . . 59
.. ..70
. . . . 60
.. .. 51
48
.. .. 35
. . . . 60
. . . . 35
34

Lcncaspis cordylinidis
l.titeaspis striota
LtMicojum

38
38
.66

Life-cycle of insects
Lime-sulphur
Loganberry

22
76
41

Long-horned beetles . .
Long-tailed mealy-bug
Lupins

64
34
.... 52

Macrosiplnim roscr
Magpie-moth
Management of garden
Manure

47
. . . . 24, 55
74
. . 74

J'hthorimcea operculella . .
Plti/lloxera vastatria;

. . . . 62
46

Mealy-bugs
Mealy-wings

. . 20, 30, 32, 34
43

1'ieris rupee
Pine-tree chermes
Plant food
Plant-lice . .
Plum 34,35,36,38,
Plum-aphis
Plutella maoulipennis
Pontania proximo,
Poplar 35.
Poplar (Tall -aphis
Porina . .
Potato
Potato sickness
Potato tuber-moth
Predaceous wasps
Privet

55
.. ..46
.. .. 12
. . . . 42
40, 44, 48, 51)
. . . . 4S
. . . . 52
.. ..60
37, 38, 48, 64
. . 42, 48
. . . . 65
34, 62, 72
72
. . . . 62
.. ..78
. . . . 38
8, 15
.. ..37
25

Mcciina maoriaUs
Merodon equestris
Metamorphosis
Micromus tasmanice
Millepedes
Mites

. . . . . . 52
66
24
. . . . 28, 34
71
... 67

Moulting
Mcuth appendages of insects
Mulberry

22
.. '.'.- '.'. 19
35 36

Mussel scale of apple
Mustard
Mvrtle ....

. . . . 30, 37

. . 44, 45, 48, 52
36

Mifzus ccrasi
Narcissus

44
66 68 7-?

Protozoa
Pulrinaria camelicola
Pupa

Narcissus flies
Natural enemies
Nectarine
Nervous systems of insects
Nicotine-sulphate

66
77
. . . . 36, 44
21
76

Puparium
Pyronota festira

Quince
Radish

. . . . 25

.. .. 58

38,40,41

Northern Spy
\orins cardlnalis
TCi/c-temera annul ata

Oak

. . .... 47
32
. . . . 24, 55

37 51

RagNvort

. . 24, 56

Oak-scale
Odontria sealandica,
Oecetic-n-s omnirorus
Oleander
Oleander-scale

37
. . . .. 57,64
56
. . 34, 35, 36, 40
40

Rape

45 48

Raspberry
Red currant
Red oil ',
Red orange-scale
Red spider

36,41,67
.. ..44
.. ..76
.. ..40

68

Olearia forsteri
Olearia gall-midge

60
.... 60

Itldzoglyphus hyaointhi
Rhododendron
Khophalosiphitm nymphcece
Rhopluilosiphum persicce
Root-knot eehvorni of tomato. .
Rose 35, 38, 40, 41,
Rose-aphis

. . . . 68
.. ..47
.. ..48
. . • . . 44
. . . . 73
47, 51, 58, 67
42 47

Olive-scale

30 35

Onion
Orange-
Orange-scale

66
35, 40, 51
40

Orchids
Orcus cli(ily~bceus
Oviparous

. . . . 36, 40
. . . . 36, 40

4.9

Rotation of crops

. . . . 75

Ovipositor

21

Round-headed borers

ftaissetia hemispherica
Kaissetia olece
San Joso scale
Scale insects

.. ..64

. . . . 36
.. .. 35
. . 32, 38
. 29

Palms
Paratetranychus pilosiis
Paris green

. . 34, 35, 36. 40
67

76

Paropsis dilatata

. 50

83

Scylla .
Seasonal liistory of insects . . .
Seed*, damage to
ticsia tipuliformis . - . . '
Sjiailot .... .. .. ,. .
Shepherd's purse
Silver-fish .

Page
. ... 66
. .. 22
65,66,71
. . . 61
. .. 66
. 44,52
26

Tortrix postvittana
Tree-lucerne

Page
.51
. . . . . 64

Trialeurodes vaporariorum
Tui ..
Tulip . .
Turnip
Turnip-fly
Turtle-scale " . .
Typhlocy'bd australis

Vallota . . . . . .
Vegetable caterpillars
Venusia rernculata . •
Vertebrates .. .-.^ ..
Violet
Viviparous

Walnut . .
Watercress
Water lilies
Wattle ..
\Yax-eye
Weta . .
White butterfly . .
White-flies

48
35
. . . . 66, 68
.. .. 45,48
'57
36
48

. . .... 66
65
. . .... 56
7
68
42

.... ..35
. . . . 46, 52

. . . . . . 48
.... 32,41
35
17
55
. . . 48

Slues

8 71

Smaller narcissus fly ....
Snails ....
Soil f u migration

. ..66

8,71
. .. 76
. .. 54
54

Sphinx convolvuli
Sphinx moth

Spiders
Spravs

8,67
75

Springtails
Spruce
Steam sterilisation
Steel-blue ladybird

. .. 66
. .. 46
. .. 74
. 36. 40
. .. 76
. 64, 68
. ... .65
. 58, 65
.. 66

78

Stomach poisons
Strawberry
Subterranean grass caterpillars
Sulphur smudge
Syrphids

Tachinids

Tetranyclius telarius
Thrips . .
'Thrush, '
Tobacco

. .. 68
. 27, 48
. ..35
54 73

Willow
Willow saw-fly
Wings of insects
Wireworms
Wistaria
Woodlice

35, 37, 38, 60, 68
60
20
65
34, 35, 36
8,70

Tomato 47,
Tomato^, root-knot eel worm
tomato 'stem-lx)rer
tortoise beetle

54, 62, 73
. ..73
. .. 62
. ..59

Woolly-aphis
Woolly-bear

. . . . 42, 47
. . . . 24. 56

14 DAY USE

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