c

State Gallege of Agriculture

At Cornell University
Ithaca, N.Y.

Library

Ornell University Library

Cc
SB 603.C4
The garden doc

ANN

tor; plants in health and

iii

Cornell University

Library

The original of this book is in
the Cornell University Library.

There are no known copyright restrictions in
the United States on the use of the text.

http://www.archive.org/details/cu31924003680802

THE GARDEN DOCTOR

PLANTS IN HEALTH
AND DISEASE

COUNTRY
PE, Se

THE
GARDEN DOCTOR

PLANTS IN HEALTH
AND DISEASE

BY

FREDERICK J. CHITTENDEN

F.L.S., V.M.H.

DIRECTOR, ROYAL HORTICULTURAL SOCIETY'S EXPERIMENTAL “GARDENS,
WISLEY

LONDON :
PUBLISHED AT THE OFFICES OF “COUNTRY
LIFE,” Lr. TAVISTOCK STREET, COVENT
GARDEN, W.C.z, & BY GEORGE NEWNES, Lrp.,
SOUTHAMPTON STREET, STRAND, W.C.2.
NEW YORK: CHARLES SCRIBNER’S SONS
MCMXX

PREFACE

Tuts little book makes no claim to originality.
It aims merely to give a short and simple account
of some of the common troubles met with in
gardens, and where they are known, methods of
meeting them that have proved effective. These
methods have been suggested by many different
workers in different lands, and I, no less than
every other garden lover, owe a debt of gratitude
to them which I take this opportunity of acknow-
ledging. The good there may be in this book is
theirs, the faults my own.

FRED. J. CHITTENDEN.

September 1920.

CONTENTS

cmap, PAGE
PREFACE . . 3 - j ‘ F 2 v

I. Taz Puant In HeantH . 5 ‘ . . 1
II. Causes or Itt-Heatta mm Puants . ‘ . 19
III Narvurse or Funeus Attacks . . , - 42
IV. Treatment or Funeus ATTacks a ‘ . 56
V. Symptoms or Funevs Attacks. ‘ é . 65
VI. Animat PEsts of THE GARDEN : . » 102
VII. Nature or Insect Atracks . . : . 106

VIII. GengraL Symptoms or Insgeot and Mire
ATTACK é z 2 - é é . 110

IX. Mersops oF DEALING WITH Insect AtTack . 116

X. INSECTICIDES, ETC. . ‘ ‘i ‘ , . 132
XI. FRIENDS oF THE GARDENER. 3 . . 136
XII. Sprayine . . ‘ ; . A : . 143
InpEX . 3 ‘ ‘é : . . 149

vii

ILLUSTRATIONS

Plants of Furrowed Duckweed

Skimmer made for clearing Duckweed .
Peach Leaf-curl . ‘

Apple attacked by Bitter-pit

Rose Leaf attacked by Black-spot

Rose Stem badly cankered .

Rose Shoot and Leaf attacked by Mildew
Rose Leaf attacked by “ Rust” Disease .

Young Apple Shoots attacked by American Blight

Apple Shoots attacked by Canker
Stereum purpureum on Stem of Apple .
Apple attacked by Scab Disease .
Wisley Trap for Turnip Flea Beetle

A Simple Mouse Trap

Club Root on Brussels Sprouts

Célfery Fly ye oe
Pew and Bean Weevils . j 7
“Winter Moths . a ‘i

oS Beetles and Wireworms
ackey Moth Caterpillars

Pears cracking . . ‘ . . .
ihe PearMidge . . . «© «6

ix

FACING PAGE

22
23
38
39
44
44
45
45
66
67
68
69
72
72
73
74
74
75
75
90
- 90
- 91

The Garden Doctor

Potatoes attacked by Wart Disease
Orange Rust Fungus on Stem of Briar.
Rose Leaf damaged by Thrips

Transverse Section of Diseased Daffodil Bulb

Daffodil Fly . F ‘ ‘ "
American Blight

Daddy-Longlegs ‘i

An Old Device for trapping Slugs
Common Cockchafer .

Black Currant Gall Mite

Thrips

Snake Millepedes a
A Grease Band in Course of Preparation
Grease Band ready for Use .

A Trap for the Caterpillars

An Ordinary Hay Band

Galls on Flowers of the Ash

The Oak Spangle Gall

Hover Fly.

Ladybird .

Lacewing Fly ‘
Spraying Apple Trees at Wisley .

FACING PAGE

94

95

95

98

99
106
106
107
110
110
111
111
126
126
127
127
132
133
136
137
137
142

Section of Apple Shoot bored by Caterpillar of the espe

Moth 3 : z :

143

THE GARDEN DOCTOR

CHAPTER I

THE PLANT IN HEALTH

No one can attain an intelligent conception of the
meaning of disease unless he appreciates the meaning
of good health. In old time, “ blight,” an expression
which covered all mysterious sicknesses, was regarded
as punishment imposed by an outraged Deity for
some transgression, wilful or unconscious, of laws
which the sufferer only imperfectly knew. “Blight”
generally is a punishment, and often a thoroughly
just punishment: the perfectly natural and in-
evitable result of the transgression, wilful or un-
conscious, of natural laws which the sufferer only
imperfectly knows. A thorough understanding of
those laws, and a rigid abstention on the part of all
from transgressing them, would do more to eliminate
disease than all the drugs of all the physicians of all
the ages. This is a general truth, and applies to our
treatment of plants as well as to ourselves. Our

1 B

Health

knowledge of those laws is imperfect, but some of
Nature’s secrets have been wrested from her, and not
all “ blight ” need now be regarded as beyond our
power to avoid.

When a living thing is in health every part of
it is performing its allotted task perfectly, and all
parts are working harmoniously. As a result, just
as with a perfectly adjusted machine, its output
reaches its highest efficiency. Let any part of the
machinery get out of adjustment and the efficiency
at once falls. So with the plant; and, except that
it is to some extent self-adjusting, a plant is very
similar to a machine: the derangement of any
one part will be likely to affect the whole. It is
important to remember that its powers of self-
adjustment are limited.

The natural aims of a plant are two: to build up
and maintain its own body, and to produce offspring.
It may, and often does, sooner or later, sacrifice its
own body to attain the second object, as in all
annuals and biennials, but the first must be gained
to some extent before the sacrifice is possible. The
designs of the cultivator are not always those of the
plant. He frequently wishes to cause the develop-
ment of some part of the plant out of all proportion
to the rest, and the plant strives to respond to his
endeavours, but not infrequently at some risk to
itself and to its powers of resisting disease. He
often selects forms which in nature, because they

2

Congenial Surroundings

are less fit to struggle for place than their fellows,
would not survive, and by isolating them removes
the need for competition. He perpetuates a form
which pleases him, but which is less efficient in
performing its functions, and which is therefore
a weaker and more delicate variety. In seeking to
attain his ends he often oversteps the bounds which
limit the plant’s powers of self-adjustment.

It must not be supposed that plants reach their
most perfect development when growing wild, or
in their native homes attain their ends with the
greatest degree of efficiency. It is, in fact, com-
paratively rare to find a plant in Nature so placed
as to perform all its functions fully. All one can say
is that a wild plant is attuned to its environment to
a greater or less extent. It has to compete with
others, and not infrequently it fails to establish itself
under the conditions that suit it best, either because
circumstances prevent it finding them, or because
other plants oust it from them. The cultivator
may often provide better environment than the
plant has when growing wild; then he will secure
well-developed plants in good health.

-~ Every species has its own best environment, and

every gardener knows that all the varieties even of

one species do not thrive alike within the same

environment ; possibly even individual plants differ

in their precise requirements. Though this is so,

and while it would be manifestly impossible to deal
3

Plants Breathe

with the likes and dislikes of even the commonest
garden plants individually, yet there are certain
facts that are true for all plants alike, and, bearing
them in mind, the cultivator can approach the
attempt to cure or prevent disease with some hope
of doing it intelligently.

A plant is a complex organism every part of
which has its own functions to perform, and its own
special requirements to enable them to be performed.
There is one function, however, which is performed
in every part of the plant body which is alive.
Every part of the plant breathes; that is, every part
of the plant takes in oxygen from the air, and gives
out carbonic-acid gas into the air. The gases pass
through the delicate walls of the youngest roots,
through special openings called lenticels on older
roots and woody stems (they can be easily seen on
smooth stems as light specks on the bark), and
through minute openings in the skin of leaves and
young stems, which can be opened or closed at need,
and which are called stomata. Provision is made
all through the plant by means of spaces between the
cells of which it is composed for the air to pass freely
to every part. Water-plants obtain oxygen from
that dissolved in the water which surrounds them ;
all others obtain it directly from the air. Breathing
is as necessary to plants as to animals; fresh air is
as necessary to a plant as toa fire. Breathing goes
on whenever the plant is active, and the more active

4

Use of Breathing

it is the more rapidly does breathing occur. It goes
on night and day, and rises with every increase in
temperature until the heat is too great for the plant
to sustain, By it the plant obtains the energy
stored up in its food, and is thus enabled to perform
all its other functions. Without it all activities cease,
and after a time death ensues. It becomes active
with the moistening of the seed; it finally ceases
only with the death of the plant. Any interference
with free breathing results in lowered efficiency
and in ill-health.

The part of the plant most likely to suffer in
cultivation is that which is underground. Few
cultivated plants are able to obtain sufficient oxygen
from water, and the soil cannot, when saturated with
water, hold enough air to supply these parts, and it
is upon this fact that the value of good drainage
depends; and to the interference with root-breathing,
the evil practices of over-watering and of standing
plants for long periods in saucers of water owe their
bad results. The breathing of the stem and leaves
is, as a rule, only likely to be interfered with when
something is deposited on the leaves which tends to
choke the openings through which the gases pass.

~ Before passing to a brief consideration of the

special functions of the various parts of the plant,

the part temperature plays in plant life may be

alluded to. The performance of every function of a

plant is more or less dependent upon temperature,
5

Heat and Plants

and goes on more rapidly at a higher than at a
lower temperature. A temperature of, say, 60° F.
would not, however, hasten the performance of any
one function to the same extent in all plants alike, nor
does the most efficient performance of the separate
functions in any one plant all occur at the one
temperature. The best temperature for a plant is
a compromise between the different temperatures
at which its several functions reach their most
efficient working, and it varies with different plants,
and with the same plant at different periods in
its life. There are, unfortunately, no observable
characters by which one can tell what range of

temperatures will best suit a given plant, and only~,

experience can decide, although indications may be
obtained by a knowledge of the distribution of the
plant and of its relationships. A higher or a lower
temperature than that which suits the plant best is
bound to produce ill effects in it. A very high
temperature (usually anything over about 140° F.)
causes death, so also does a low temperature; but
whereas most plants die at about the same tempera-
ture in the upper range, some can bear a far greater
degree of cold than others. The exact degree will
depend partly upon the condition of the plant, but
very largely upon its nature.

We turn now to the special work of the different
parts of the plant. The root has two general
functions. It absorbs the water required and certain

6

Root Work

substances used by the plant in building up its
body, and it fixes the plant in the soil.

The younger parts of the root have thin, delicate
walls through which (although no visible holes are
present in them) water and substances dissolved in
it may easily pass. The extent of surface of these
parts of the roots is increased by the outgrowth of
many cells so as to form delicate projections. These
outgrowths are called root-hairs, and though their
life is short, they are continually replaced by new
ones as the root lengthens and branches, and they
always occur within a short distance of the tips of the
roots. All the water, etc., absorbed by the plant
must find its way through the surface of the root-
hairs or of the delicate roots which produce them.
The useful water in the soil forms a film over the
surface of the particles of which the soil is composed,
and from these particles certain substances are
dissolved. In order to obtain the water the root
and root-hairs must be in close contact with the
soil particles.

Chemical analysis of plants has shown that the
following elements are universally present in them,
viz. carbon, hydrogen, oxygen, nitrogen, sulphur,
phosphorus, calcium, magnesium, potassium, iron,
chlorine, silicon, and sodium. Experiments have
shown conclusively that the first ten in this list are
essential, the others needless or merely accessory.
Except carbon, all are obtained from the soil in

7

Chemical Constituents

solution. The first six are constituents of the
living stuff itself, the remaining four each play their
several parts, potassium assisting sugar formation,
iron being essential in the formation of the green
colouring matter, and so on. If either of these
chemical elements is present in too small quantity in
a soluble form in the soil the growth of the plant is
interfered with. If certain of them are present in
too great quantity as compared with the others
either part of the plant is encouraged to develop at
the expense of the other parts, or parts are injured or
destroyed. If the soil solution is too strong, absorp-
tion of water by the plant is retarded or actually
prevented. Only when the soil solution contains
sufficient but not excessive quantities of soluble
salts combining the essential chemical elements can
water and earth-salt absorption go on normally and
the plant be supplied with the requirements for
healthy life. The rate of absorption of water and ~
earth-salts is to a large extent governed by the rate
at which each constituent of the solution is used by
the plant, or, in the case of the water, got rid of.
Ideal conditions for absorption by the root are
provided when the water supply is arranged so that
every soil particle is kept bathed in a weak solution
of all the earth-salts which the plant requires, while
the spaces between the particles are filled with air,
when the soil temperature is sufficiently high, for
the rate of absorption rises with the increase of
8

Firm Planting

temperature up to about 90° F.; and when the
delicate root-hairs are in intimate contact with the
soil particles.

The intimate contact of the root-hairs with the
soil particles effects the fixing of the plant, which
is the other function of the root. Frost, flooding,
meee soil cultivation, bad planting, such, e.g.,

“hanging plants up,” winds, burrowing animals
and the like, may break the contact or render it
difficult to effect, as may readily be seen.

The coarseness or fineness of the root-fibres and
other structural peculiarities, into which we cannot
enter here, are in the main connected with the kind
of soil, clay, sand, etc., in which the plant is most
at home. The firmness of the soil also influences
the kind of shoot-growth made, for it modifies the
water supply. The firmer the soil the more compact
the growth.

The stem, be it long or short, simple or branched,

has two main functions: to convey materials from

place to place in the plant and to produce leaves
and place them where they can make the best use _
of the light. -

A section across a stem shows, as a rule, a central
pith surrounded by a cylinder of wood ; this again
by soft inner bark or bast with probably fibrous and
green tissue outside of it, and lastly, either a thin skin
or a layer of cork. Between the wood and the soft
bast lies a very delicate ring of cells, called the

9

Stem Structure

cambium, which by its division adds to both the
wood and the soft bast and so thickens the stem.
This part of the stem is really a series of cords lying
side by side, each consisting of wood inside, cam-
bium, and soft bast. In other plants there is no ring:
instead, the bundles of wood and soft bast tissue are
scattered about, forming long cords through the stem
tissues, and no cambium is present. In any case, one
end of the cords or their branches lies in the leaves
where the veins are made by them, and the other in
the roots, where they reach the uttermost rootlets.

The wood consists of fibres for strengthening, and
long tubular vessels along which water or earth-
salts are pushed and drawn up from the root to the
leaves. All water passes up the wood.

The soft bast consists mainly of peculiar tubes
along which the food made in the leaves passes to
any part at which there is a demand for it, arising
either from its being used to form new tissues, or in
breathing, or through its storage.

There is therefore an upward passage of water
containing earth-salts, and a downward passage of
water containing manufactured food, and each has
its own proper channels. The channel for the water
and earth-salts lies toward the inner part of the stem
and the upper side of the leaves ; the channel for the
food on the outer part of the stem (just on the inner
side of the bark) and along the lower side of the leaf-
veins. Have you noticed aphides feed on the lower

10

Stem Work

surface of leaves where the food is most easily
reached ?

The second function of the stem will be more
readily appreciated after we have briefly discussed
the functions of the leaves. All leaves are produced
in buds and in age-order, the younger nearer the
apex of the stem bearing it. The stem carries
them into the light, and the spaces at which the
leaves are set may be more or less lengthened as the
stem grows in order to effect this, or the stem may
twist between the leaves for the same purpose.

The arrangement of the leaves on the stem and their _

disposal are both connected with the need for light.

The special functions of the leaf are also two:
the making of food and the getting rid of water.
Both these functions, as we shall see, involve the
passage of gases into or out of the leaf, and this is
effected through the curious pores called stomata
which are found in the skin of the leaf, mostly on its
under side. These pores are surrounded by two
guard-cells, which open when the plant is fully
supplied with water or when it is exposed to light,
and which tend to close as the water supply or the
light fails, and may close completely.

Food-making is a power which, of all living things,
green plants alone possess. The raw materials for.
it are water and earth-salts, which are obtained by
the roots, and carbonic-acid gas, which passes from
the air through the stomal openings into the leaves.

11

Food-making

(The plant, of course, produces carbonic-acid gas
inside the cells themselves in breathing, but far too
little to supply its own needs in food-making. It
therefore draws upon that produced by animals and
by fires.) The process of food-making is a very
complicated one, but the first visible product is
starch. This is made from the water and the
carbonic-avid gas, the former being split up into its
constituent oxygen and hydrogen, the latter into
carbon monoxide and oxygen. The two oxygens
are no longer wanted and pass off into the air. The
carbon monoxide and the hydrogen are caused to
combine together to form sugar, which is further
changed to starch.

To do this work of food-making power is wanted,
just as it is to do any other work. We have already
pointed out that a certain temperature is required to
enable any work to be done, but heat alone will not
supply the energy for doing this special work: the
only form of energy which can be used is derived
from sunlight or light containing similar rays. When
the rays of light fall upon a leaf they do not all pass
through it, but some are arrested by the green colour
which is so characteristic of foliage (it is present even
in purple leaves, such as those of the purple beech or
purple plum). The rays so absorbed are used by
the living stuff of the leaf as a source of power, and
only when light falls upon a green leaf can food be |
made. Anything that interferes with the falling

12

Value of Light

of light upon the leaf reduces the power at the
disposal of the leaf; even glass of ordinary kinds
has that effect.

Curiously enough, very bright light has a destruc-
tive effect upon the green colour, but the plant has
the power of protecting it from destruction by
removing the grains containing it from the direct
rays of the sun when these threaten it too severely. «
Plants which naturally grow in more or less deep
shade are able to make use of even the faint light
that reaches them, but it may be so faint that —
although they can make enough food by its aid
to sustain existence, yet they make insufficient to
enable them to flower.

The making of sugar may be looked upon as the
beginning of the food-making process, for plants,
no less than animals, require other foods. The next
step in building the more complex and valuable
foods is the addition of nitrogen to the carbon,
hydrogen, and oxygen of the sugar. The nitrogen
is derived from the soluble nitrates and salts of
ammonia absorbed with the soil-water. After this
combination is effected, sulphur from sulphates and
phosphorus from phosphates, both of which have
similarly come from the soil, must be brought into
chemical combination with the other elements before
the material is available out of which the living stuff
itself is made. The steps by which these combina-
tions are brought about, and the conditions upon

13

Loss of Water

which they depend, are too indefinitely known to
warrant any description of them in a simple account
such as this, and it must suffice to say that the iron,
potash, calcium, and magnesium which enter the
plant and are known to be essential to it, are of use
in promoting the chemical changes which result
finally in the building up of the living stuff of the
plant, and in its subsequent changes which are
expressed in what we term living activities.

The second special function of the leaf, the
passing-off of water, is necessary in order to con-
centrate the various earth-salts sufficiently to make
them useful, and to keep the plant cool.

The solution taken in from the soil is as a rule,
and in the vast majority of plants, exceedingly weak. °
In order to obtain enough earth-salts much greater
quantities are therefore taken in than are necessary
to distend the cells and to provide water, as one of
the raw materials for food-making, and the surplus
must be got rid of. —

The burning rays of a vertical sun in a cloudless
sky would soon raise the temperature of the plant-
body above what the living stuff can withstand
but for the fact that much of the heat is used in
evaporating water which passes off through the pores
in the leaf, which we have already mentioned.

Water is essential to all plant activity. The
living stuff of the plant can have no active existence
unless it is saturated and distended with water ;

14

Water Supply

nothing enters or leaves the plant unless it is dis-
solved in water ; water is the vehicle by which all
substances (except the air in the spaces between the
cells) is conveyed from place to place, and even the
oxygen and the carbonic-acid gas are brought into
contact with the living stuff dissolved in water ;
and water is one cf the necessary raw materials for
food-making.

To obtain the most light and to get rid of as much
water as is necessary or as the plant can afford, are
the problems which face every plant in the deter-
mination of its leaf structure, and many and wonder-
ful are the devices for meeting the two different ends,
the one demanding a large surface, the other often
rendering a contracted one absolutely essential.
Contrivances for getting rid of enough but not too
much water determine more than anything else the
form and habits of a plant. It is not too much to
say that it is possible to tell more about the con-
ditions under which a plant should be cultivated
(except as regards the temperature) by a con-
sideration of its foliage than by anything else, and
the most successful plantsman will be he who best
fits conditions, by choice of compost, regulation of
atmospheric moisture, and use of the water-pot and
other means of regulating soil-moisture, to suit the
water requirements of his charges. There are more
plants murdered by injudicious use of the water-
pot than by any other means, and there is no better

15

Watering

test of the efficiency of a gardener than that imposed
by the operation of watering. A gardener who\\\.
studies the structure of his plants with a view to
realising their water requirements, and has the
opportunity and gumption to regulate his treatment
accordingly, will be little troubled with plant diseases. .
This is not the place to describe the various
modifications of leaf-form devised to regulate water
supply, but it should be clearly realised that large-
leaf surface, dry air and draughts, bright light and
high temperature, increase the amount of water lost
by the foliage, and the loss can be made good only
by absorption of water by the roots. A small
amount of foliage, moist air, shade, and low tempera-
ture diminish the loss. Finally, it may be said that
the plant can, by opening or closing the pores in its
leaves, regulate the loss to a considerable extent,
and that it can within certain limits alter the
structure of its foliage to suit changed conditions,
as long as the conditions are brought about gradually,
as in the process of “‘ hardening off.” Different
plants are able to make these modifications to
different extents, and some only to a very slight
extent. z
The remaining organs of the plant, the flower,
fruit and seed, are connected with reproduction,
and broadly speaking, if the other organs are in good
working order these will do their work efficiently. ~~ ©
Flowering is usually connected with a quiescent
16

Food Storage

rather than an energetic state, and flower production
is usually greatest when the balance between water
supply and food store is in favour of the latter ; ¢.g..
slightly pot-bound plants flower more freely than
over-potted ones.

More food is usually made by a plant in health
than is necessary for its immediate needs, and this
is stored in some part of the plant either for its own
needs in the future, as the starch in the medullary
rays of the vine stem, and the sugar in the beetroot,
or to give its offspring a start in life. Such food
stores are naturally attractive to parasites, and not a
few plant pests thrive upon them to the detriment
of the plant’s future, or the strangling of its progeny
at their birth.

The final result of all the plant’s activities, and
dependent upon their due performance, is growth.
It is a complex process and ‘dependent on a sufficient
supply of manufactured food made by the foliage,
enough water to distend the cells to their full extent
and to keep them distended (and therefore, probably,
most active at night), a temperature suitable to
promote all the necessary chemical changes (varying
with each different kind of plant), a supply of oxygen
for breathing purposes, and the absence or prompt
removal of all substances detrimental to the well-
being of the plant. ca

The kind of earth-salts available has some
influence upon the kind of growth produced, and

17 Cc

Effect of Manures

upon the localisation of growth. Thus soils rich in
combined nitrogen (whether naturally or by the
addition of manures) promote the growth of foliage,
perhaps at the expense of flowers; plants growing
in soils where available potash is abundant usually
store more starch or sugar than where it is only
barely sufficient; while abundant supplies of
phosphates appear to encourage flowering, and
especially fruit and seed production. These are,
however, but examples of the power of response to
changes in their surroundings possessed by plants,
and might be multiplied almost indefinitely for each
variation in all the surroundings which we have
considered.

18

CHAPTER II
CAUSES OF ILL-HEALTH IN PLANTS

Just as a plant is in perfect health when all its organs
are perfectly attuned to its surroundings, and no one
function outpacing the others upon which it partly
depends, but all concerting in harmony for the
common good, so when anything occurs beyond the
power of the plant to adjust itself to and discord
arises, ill-health will supervene and the whole suffer.

The discord may be due to changes in the plant
itself, possibly perfectly natural and occurring in
the due sequence of its development, or it may be
due to changes in the environment. In the latter
we have to include not only the soil, water, atmo-
sphere, temperature, and light, but also its living
neighbours, and especially such as are likely to prey
upon it among animals and fungi.

The changes which occur naturally in the plant
itself are generally looked for, and are less deplored
than those which bring about disease through acting
from without. A good example is provided by those

19

Exhaustion

plants which “‘ wear themselves out ” by producing
seed; all the food made and the water absorbed
are directed to perfecting parts which are unproduc-
tive so far as the individual is concerned. The
flowers, fruit, and seeds are either not green at all
or consume a far greater quantity of food than
their small amount of green tissue enables them to
produce. In them the individual actually dies of
starvation, starving itself to give its offspring a
good start in life. Annual and biennial plants are
such, and not a few perennials delight us for a time
and are no more, for the same cause. Who has not
deplored the loss after its brilliant display of such
a mule pink as “ Napoleon III.” ? Yet it is not
doomed to die if we prevent it flowering when it
wants to, but will then give us plenteous shoots for
propagation. So too may the life of annuals be
prolonged by restricting their flower production or
removing their seed pods before they develop too
far. Indeed, in such cold regions as Central Siberia
even such confirmed ‘‘ annuals” as the common
shepherd’s purse outlive more than one growing
season.

Interesting as this phase of plant-life is, more
important to the cultivator is the set of troubles due
to external factors such as unsuitable surroundings
and attacks of living agents. A study of the subjects
briefly outlined in Chapter I. will indicate where
there are chances of the surroundings being faulty,

20

Effect of Grass on Trees

but in addition to those mentioned there, the presence
of substances detrimental to plant growth, either in
the soil or in the air, have to be dealt with, and in
a few instances in the cultivation of garden plants
we have cases where plants actually come into
competition with one another quite apart from
overcrowding through too close planting. We
may deal with these first.

One of the most frequent checks imposed upon
trees is the presence of grass about their trunks.
It is especially seen when young fruit trees are
planted in grass, is most marked when the grass
completely covers the ground, but is still seen when
several feet are kept clear around them. Experi-
ments seem to show that it is through no direct
interference with water, air, or earth-salt supply
that the marked check to growth is caused, but
rather to the production of some substance dele-
terious to the trees by the grass, or the decay of the
remains of the grass, roots, etc. The remedy is to
remove the grass, and the result of this treatment
is, so long as the poisonous effect has not been in
operation too long, rapid.

A second competitive effect is often seen in water
where water-lilies and other aquatic flowering plants
are often damaged by being smothered with the
thready green masses of “ flannel weed,” which grow
with extraordinary rapidity. This flannel weed will
grow in any exposed piece of water, but is readily

21

Flannel Weed

kept down in wells and tanks by covering them
with an opaque cover, as it depends upon light. The
ordinary methods of weeding, or rather raking out
of the stuff, are only partially successful. Fish often
eat considerable quantities of it, and if a sufficient
number can be kept in the water, they will do much
to keep it in check. If it still persists, then the
copper sulphate treatment should be applied. The
quantity of water in the pond is estimated. For
each ten thousand gallons put 24 oz. copper sulphate
(blue stone or blue vitriol) into a coarse canvas bag
and draw the bag by means of a rope across the pond
in every direction until the whole of the copper
sulphate is dissolved. The very dilute copper
sulphate solution will kill the algae (or “ flannel
weed ”’) without harming fish or water-lilies. It
may have to be used again during the season, but
in still water often keeps the algae from growing for
a long time.

The third case in which plants come into com-
petition is on lawns. Here the troubles are usually
of two types, the growth of broad-leaved weeds and
the growth of moss. The composition of mixed
herbage is always determined by two factors—the
opportunity various plants have of gaining a footing,

1 Multiply the average breadth in feet by the length in feet and
the product by the average depth in feet. This will give the
number of cubic feet contained in the tank or pond. Multiply this
result by 6} (or 6-232 to be more acourate) and tke product will be
the number of gallons the pond holds.

22

PLANTS OF FURROWED DUCKWEED (Lemna trisulca).

1. Floating on water. 2. A plant magnified, and in flower
ata. 3. A flower extracted from the slit in which it 1s laid—a,
the membranous bag. 4. A fruit. 5. A seed.

me

SKIMMER MADE FOR CLEARING DUCKWEED.

Lawns

and the nature of the existing conditions. On a
lawn we usually place the plants we desire, by using
turf containing grasses suitable for the purpose,
or by sowing a mixture of seeds free from weeds.
If the conditions are favourable to the grass all goes
well, but if they are unfavourable and bare patches
arise, weeds and moss are apt to establish themselves ;
and if the conditions are then more favourable to
the weeds or the moss, the grass will gradually be
killed out and its place taken by the more favoured
tribe.

The application of sulphate of ammonia favours
the growth of grasses more than does any other
manure. It also acts detrimentally upon broad-
leaved plants if strewn upon them, and where time
permits there is no better method of killing them
than by putting as much sulphate of ammonia on
their crowns as would cover a sixpence. Where this
cannot be done sulphate of ammonia should be dis-
tributed over the lawn at the rate of 14 cwt. to the
acre (4 oz. to the square yard, or 1 Ib. to the square
rod). It may be mixed with dry soil and spread
more readily thus than by merely throwing it on
broadcast. More should not be used and may do
harm. Spring is the best time to apply the manure.

The presence of moss is a symptom that condi-
tions are not favouring the grasses. At least three
different causes may lead to the production of this
symptom, viz. lack of drainage, sourness of soil, and

23

Moss on Lawns

poverty of soil. The remedy for lack of drainage
is obvious, and the constant presence of a super-
abundance of water in the soil often results in sour-
ness. Sourness is probably due to the production
of organic acids by the action of bacteria, which
work best in the absence of air, and of a suitable
base to combine with the acids. The cause of its
production being removed it is necessary also to
remove the acid. Soil acidity may be discovered
by asimple test. A fair sample of the soil is obtained
by taking portions from various parts of the ground,
mixing them thoroughly (best done by allowing
them to dry and crumbling them up together), and
taking a sample of the bulk. This sample is
moistened with pure water, and a piece of blue
litmus-paper is laid in close contact with the moist

soil and left for half an hour under a tumbler. If ©

at the end of that time the litmus-paper has acquired
a distinctly red tint the soil is acid. The remedy for
soil acidity is lime, and a dressing of powdered chalk
will often help to encourage the grass and oust the
moss. Use it in autumn at the rate of 1-2 tons to
the acre (4-1 1b. to the square yard, or 15-30 lbs. to
the square rod).

The third source of a mossy condition is poverty
of soil. This is always likely to arise where the
lawn is mown regularly and the clippings removed,
and such lawns benefit by an annual spring dressing
of good sifted loam, sandy loam answering the

24

Sour Soils

purpose well. This may be applied at the same
time as the sulphate of ammonia, and a dressing of
superphosphate is often of great benefit, the latter
being used at the rate of 2-4 cwts. to the acre (2 to
14 oz. to the square yard, or } to 3 lbs. to the square
rod). No definite instructions for soil treatment
to suit all places and all kinds of lawns can be given,
but treatment such as has been advised will meet
most cases.

A second sort of soil acidity has to be reckoned
with in great centres of population where acid from
chimney fumes is brought down by the rain. Lime
will not protect plants from damage by this, and only
the use of the most acid-resistant grasses like Poa
annua is likely to result in the growth of even a
moderate lawn. These fumes, and the tarry deposit
which collects on the leaves and owes its presence to
the same source, do irreparable damage.

While dealing with lawns another set of troubles
may be referred to—the difficulties met with in
growing grass under trees. Comparatively few
grasses are attuned to the dim light that reaches
them under the shade of trees—most require the
full light of the open meadow. Of these few but
one or two are fitted for the peculiar treatment
lawns necessarily undergo, Poa nemoralis being the
best of them, and choice must fall upon them for a
grassy covering in such places. Even these, however,
are apt to be killed out, for not infrequently their

25

Honeydew

leaves become covered by a sticky fluid called
honeydew, which is produced by aphides or scale
insects living upon the trees above them, and which
drops down, effectively closing all the pores on their
leaves through which the various gases should pass,
and causing their suffocation or starvation. Lime
trees, while by no means the only ones, are particu-
larly troublesome cover for shady lawns because of
this. Any remedy beyond a frequent spraying
of the grass with water would be very difficult to
apply, and entail unreasonable expense.

Honeydew often falls upon other plants from
aphides and their allies, and damages them in a
similar way, and also forms a medium for the growth
of a set of fungi called black moulds. These black
moulds are not directly destructive to the plant, are
wholly superficial, and may readily be rubbed off
the leaves or fruits on which they are found. They
are, however, very disfiguring, and worse still, they
obstruct the light so that the process of food-making
is seriously interfered with. The remedy is of course
to attack the insects which are the source of the
honeydew and to cleanse the plants by spraying or
sponging with water or soapy water.

Soil acidity is a frequent cause of ill-health in
other plants than grasses. As has already been

pointed out, it is very liable to arise when drainageis __

insufficient, but it also occurs in soils devoid of lime
and in soils to which organic manures have been
26

Test for Lime

continuously added. It is indeed well to maintain
a sufficient quantity of carbonate of lime in the soil
to counteract any tendency to sourness, and soil may
easily be tested to see whether enough is present.
To carry out the test, take samples from various
parts of the plot to the depth to which cultivation
is usually carried. Crumble them up together until
they are thoroughly mixed, and then place part of
the soil in a tumbler with ordinary tap water to
wet it thoroughly. Pour upon it a little spirits of
salts (muriatie or hydrochloric acid). If noticeable
effervescence occurs the indication is that the soil
contains sufficient lime, but if there is no effer-
vescence it is desirable to add lime. It is not at all
infrequent to find that soils with a chalky subsoil
are deficient in lime so far as their upper layers go,
so that even they may need liming. Lime is added
in a variety of ways. Chalk, powdered so as to be
distributed evenly, is best suited to light soils, air-
slaked lime to heavier ; but where soil pests are to be
killed powdered quicklime, distributed at the rate
of half a bushel to the square rod in autumn and
immediately forked in, is best. Gypsum, marl, or
erushed shells are all useful mild forms of lime best
used on light and sandy loams. Gas lime of the old
type is now rarely procurable, and if used entails
the lying idle of the soil for a longer or shorter time.
The presence of lime in the soil is detrimental
to most rhododendrons, heaths, and the like, and

27

Weeds of Sour Soils

where these are intended to be grown it should not
be added.

Soils which are sour often develop a growth of
moss upon them very quickly in moist weather, and
certain weeds grow well which are absent, or almost
so, from soils containing a sufficient supply of lime.
Among these weeds sheep-sorrel (Rumex Acetosella)
and spurrey (Spergula arvensis) or dodder, as it is
called in some places, but quite distinct from the true
dodder, are the commonest, and liming the ground
does much to keep these weeds in check. Lack of
drainage is often similarly indicated by weeds, the
common borse-tail (Hquisetum arvense), called mare’s-
tail in some places, and Coltsfoot (Tussilago Farfara)
being common examples of such stagnant water
indicators. With these again efficient drainage does
much to check their spread.

Sour soil checks the growth of many plants and
encourages the growth of pests of various sorts, at
the same time laying the plants open to the attack
of the pests to an extent unknown on soils in better
heart. The acids may render it more difficult for
roots to absorb the necessary water ; their presence
may actually poison the plants, while the presence
of water in the soil where air should be causes the
suffocation of roots, and therefore a cessation of the
water supply.

This is not the place to point out how drainage
should be effected, but we may refer to one or two

28

Drainage

causes which militate against good drainage even
when it is thought to have been efficiently provided.
Drains in the open ground often become filled with
tree roots or broken in their course so that the
channel becomes filled with earth and choked. The
air supply to the roots of plants in pots is not in-
frequently interfered with by the use of dirty pots,
of pots much too large for the plants in them, by
worms carrying earth into the drainage, and by
standing plants over the week-end with water about
half-way up their pots so that they shall lack nothing.
The use of fancy pots in which to stand the ordinary
flower-pots often leads to the same trouble, which
usually manifests itself by the tips of the leaves
becoming brown. Glazed pots render watering
much more difficult than ordinary flower-pots, and
novices often come to grief in using them, as did the
artistic (?) individual who painted the flower-pots
with a bright green paint and so filled up all the
pores through which air was wont to pass.

Plants in ill-drained and sour soil often indicate
the condition by the unhealthy yellowish tint of
their foliage. Pallor is almost always a symptom
of ill-health, and if accompanied by stunted growth
and by brown tips to the leaves, will usually be
found to be due to interference with root activity
through ill-drainage. Some other causes leading
to interference with root-action produce similar
symptoms, but that is the most common.

29

Acid Water

Some pests, such as the troublesome leather-
jacket, the grub of the daddy-longlegs, or crane-fly,
are more prevalent in wet than in properly-drained
soils.

In manufacturing districts water standing before
use for watering and syringing plants not infrequently
absorbs poisonous fumes of sulphurous acid and
chlorine from the air, and plants on which it is used
naturally suffer. Some good may be done by placing
lime in the tanks to neutralise these substances. The
same fumes often do damage to the foliage by enter-
ing the pores of the leaves with the oxygen and
carbonic-acid gas or by being dissolved in the drops
of water which exude from the tips or teeth of many
leaves when the air is moist. The cells with which
the poisons come in contact are killed, and brown
spots occur in the leaves or along the margins. At
times arsenical fumes escape from smelting works
and do much damage. Similar damage was not
infrequent when the old flue-system of heating was
in vogue and fumes from the flue escaped into the
houses, and at the present time sufficient care is not
always taken to ensure that fumes from the stoke-
hole are effectively excluded from the house. Gas
and fumes from gas lamps are equally detrimental.
We have had cases recently brought to our notice
of similar poisoning by fumes from cresoted wood
and the like.

When these causes are operative it will be found

30

Burning

that many different plants are suffering from the
spotting, though the spots are not all of the same
shade of yellow or brown, whereas a fungus attack
will be confined to one or at most a few kinds of
plants in it, as with that of most animal attacks
except perhaps red spider, when the pests themselves
will be evident to the careful observer. This will
serve to distinguish the source of this trouble from
that of insect or fungus attack in most cases, but
not from the trouble known as burning or scalding.
The escape of coal-gas or acetylene from leaks in
underground pipes not infrequently leads to the
death of roots of trees and shrubs in the vicinity.
Burning or scalding is characterised by the
presence of white, yellow, or brown spots on the
foliage (only occasionally at the edges) and is most
frequent on leaves of rather thin texture. It
occurs also on grapes. It is often attributable to
defective glass (i.e. glass of uneven thickness, or
containing bubbles) concentrating the sun’s heat on
certain spots, and plants placed in these spots will
suffer. Similar results follow even a short time of
water shortage in some delicate-leaved plants such
as Primulas and Begonias, especially when the air as
well as the soil is dry, or lack of ventilation with
vines, etc., or syringing with a falling temperature
instead of with a rising one, which is particularly
detrimental to orchids and leads to the black-
spotting of the foliage or pseudo-bulbs. Exactly
31

Value of Potash

how this scalding arises is not very clear, but it
is probably due sometimes to a great local rise of
temperature leading to the too rapid withdrawal of
water from the cells, and at others to a rapid fall
in temperature perhaps bringing about a similar
result, and in any case leading to the death of cells
in circumscribed areas in the leaf. The preventive
must be found by a consideration of all the circum-
stances and the removal of the cause, adjusting
matters so as to maintain a proper degree of moisture
in the air in relation to the temperature of the house
and the amount of light the plants are receiving.
This is, of course, difficult to achieve for every plant
when many kinds of plants are grown in one house,
and it then becomes a question whether attempts
should be made to cultivate any others than the
more accommodating ones, or in the alternative to
restrict the inmates of the houses to some special
favourites with similar requirements.

Returning now to the effect of the chemical
constitution of the soil on health, we find that an
excess of any or a deficiency of the ordinary earth-
salts produces more or less definite symptoms.
We have already pointed out the more obvious parts
played in plant nutrition by the principal chemical
elements, and the result of a deficiency of any one of
them is readily seen. It only remains to say that
deficiency in potash supply lays many plants open
more readily to fungus attack, and that deficiency

32

Avoid Excess

of phosphates is often recognisable by a purplish
tinge in the foliage of grasses, especially of barley
and the like.

An excess of nitrogen leads to a lush, sappy
growth which falls ready victim to fungi and is much
more liable to damage by frost than more sturdy
tissue. Such growth is characterised by a deep
green colour, large watery foliage, and often long
internodes, which are not, however, thin. It often
follows the too liberal use of organic manures or
nitrate of soda and sulphate of ammonia. Soils
which grow chickweed and fat-hen (goose-foot,
Chenopodium album) vigorously are usually suffi-
ciently supplied with nitrogen.

Excess of lime is characterised by yellowing of the
foliage, which may be of rather small size, and may
be entirely or only partially devoid of green colouring
matter. The growth is usually sturdy and the
internodes short. The lack of green colour of course
checks food-making more or less completely, and the
result is disastrous to the plant. It may be cured
by the application of sulphate of iron to the soil at
the rate of 2 oz. or so to the square yard. Roses
and laurels frequently show this disease, which is
termed chlorosis, when growing in chalky soils.

A curious cause of infertility, not marked by any
very characteristic symptom in the plants except
general tardiness in growth, is found when the
amount of magnesia present is in excess of that of

33 D

Liquid Manuring

lime. This can be discovered only by careful
chemical analysis, and is remedied by redressing the
balance by the addition of lime.

Of the evil resulting from the presence of various
poisonous metals in the soil we need not write
except to warn against the addition of too much
borax (which has been recommended as an antidote
for flies and which does little harm when only small
quantities are used), and against the possible danger
of the too free use of arsenical poisons, which has
been reported to have resulted in considerable harm
in some parts of America.

Before dismissing this matter the use of too strong
solutions of fertilisers as liquid manure should be
mentioned. One ounce of a fertiliser dissolved in
a gallon of water is amply strong enough, and half
an ounce is usually better. If the solution of earth-
salts in the soil becomes stronger than usual the
plants have difficulty in absorbing water, and may
actually wilt on account of it, and harm rather than
good results from the application. Acting on the
fallacious reasoning that if a little does good, more
will do better, amateurs not infrequently cause
considerable damage by using too much fertiliser
in an excess of zeal and a laudable desire to excel.
Plants with delicate foliage suffer most, spots
similar to those produced by burning appearing on
the leaves, but even more robust plants are apt to
drop many of their leaves. The difficulty of absorb-

34

*“Drawn’’ Plants

ing the water from the strong solution acts exactly as
an actual lack of water does, and produces precisely
the same symptoms. If through inadvertence too
much of a fertiliser has been used, the best thing to
do is to water freely ; if the plant is in a pot, stand
the pot in a considerable volume of water for a time
so as to wash the excess out, taking care that all
excess of water is drained away when the pot is re-
moved from the vessel in which it has been standing.

Excess of water combined with a rather high
temperature leads, just as excess of nitrogen does, to
the production of sappy unprofitable growth, less
dark green, however, than nitrogen-forced growth.
When these two conditions combine with deficiency
of light, or when light is deficient and only a moderate
supply of water and heat are available, a diseased
condition known as etiolation is produced.

In extreme cases, such as can be seen in the stems
of a potato allowed to grow in darkness, no green
colour at all is developed, the foliage fails to broaden,
and the stems become greatly elongated, sappy, and
lacking in woody fibre. When less marked the plants
show all these symptoms to a slighter extent and
are said to be “drawn.” The “ drawing” is seen
-in window plants on one side, and has the result of
turning the foliage so that it can get the whole of the
light available. This kind of “drawing” can be
avoided by frequent turning of the pots so that all
sides of the plant are equally illuminated in turn.

35

Overcrowding

Overcrowding, too close planting or seed-sowing,
standing plants too far from the glass, allowing their
more vigorous neighbours to overshadow them,
shading them and forgetting to remove the shade,
are all common ways of causing etiolation. The
checking of food-making in such plants need not
again be referred to, but it may be worth while to
point out the especial danger of permitting the
condition to overtake young seedlings which have
only the slender store of food laid up for them in the
seed to fall back upon. They may be completely
ruined by it, and in any case their delicate tissues
will be laid open to attack by damping-off fungi.

Etiolation may also be induced in greenhouses
by keeping the temperature too high in winter and
urging growth when the light is naturally dim and
of but short duration. It is a wise rule that delays
seed-sowing until the “ turn of the year ’” when the
light begins to increase. Etiolated growth is almost,
and sometimes quite, useless to the plant; it may be
an actual expense, and is always a menace, as it more
readily succumbs to adversity. It is desirable in
some garden plants which are blanched before use,
but must only be induced in these after they have
been grown under conditions which have ensured
the storage of ample food to supply the etiolated
growth.

Even when light is sufficient, foliage formed in
a moist atmosphere by plants well supplied with soil

36

Warted Foliage

moisture and growing rapidly in a high temperature
is thin and papery and readily open to fungus attack.
A peculiar effect of these conditions is seen in leaves
of vines, tomatoes, and sundry other plants, where
some of the cells on the lower surface of the leaves
attain an extraordinary size through the amount of
water they contain, so that warty growths are formed
upon them. These growths not infrequently dry up
when the atmosphere becomes dry, and form brown
or almost black lumps on the leaves, which are often
attributed to fungi or insects. Attention to a proper
balance of light, air, heat, and moisture will avoid
all these dangers to the health of plants, and it must
be manifest that at times the cultivator, in his efforts
to obtain greater returns, gambles on the chance of
a plant adapting itself sufficiently to adverse con-
ditions to avoid serious damage, and if it does not
and he loses, he has only himself to blame.
Shanking of grapes is another trouble connected
with the water-supply. At certain times in the life
of a plant a greater demand for water has to be met,
and can be met only when the roots are in good
condition. We have seen that waterlogging of the
soil and other conditions may lead to the death of
roots, and it is when this has occurred that shanking
is most frequent. When the berries have enlarged
more water is called for, and if it cannot be had the
berries and the stalks that support them shrivel or
‘“‘shank.’’ An opposite result, the splitting of the
37

Splitting of Fruits

berries, occurs when water is more than sufficient,
and while it is difficult to regulate the amount the
vine shall absorb it is not so difficult to regulate the
amount it shall lose. This may be done by (1)
maintaining a drier atmosphere to encourage the
loss of water, and (2) leaving more leaves on the
laterals than is usually done.

Splitting of other fruits, such as tomatoes and
apples, occasionally occurs, especially after the plants
have been subjected to dry conditions for a time,
and then to copious supplies of water. It may be
obviated by maintaining uniform conditions, and
rendered much less likely by providing available
potash. The use of much organic manure often
results in splitting, especially in tomatoes, for it
makes the soil more moist, and the nitrogen con-
tained encourages “‘ soft” growth.

Bleeding in plants, being the loss of sap from cut
ends of stems or from wounds, robs plants of much
of the sugar and other foods which they contain.
It occurs when roots are active, foliage for getting
rid of water vapour either absent or very sparse,
and wounds leave an open passage for the flow.
Pruning in spring after the rise of the sap is likely
to prove detrimental and to weaken plants, and if
it must be done the ends of the pruned shoots should
be closed by means of “‘ styptic.”” Removing shoots
in summer (unless almost all the foliage is removed)
is not followed by bleeding, since the remaining leaves

38

PusvcH LEAr-coRL.

APPLE ATTACKED BY BITTER-PIT.

; Bitter-pit
suffice to get rid of the available water without loss
of sugar, etc.

Enough has been said to show that some of the
chief troubles met with in cultivation are due to im-
proper relations between water available at the root
and water vapour given off, and certain mysterious
diseases of plants, e.g. the bitter-pit of apples and
pears, characterised by the presence of brown spots
of dead cells in the flesh of the fruit, usually some
little way beneath the skin, are probably traceable
to the same source. Attention to this important
point should be the aim of all who attempt to
cultivate plants, and almost all cultural operations,
from the preparation of the soil to methods of
grafting and budding, have a more or less direct
relation to it.

Not only do plants suffer directly through in-
attention to the maintenance of proper conditions,
but the weakened plant is more liable to attack by
fungi and bacteria, and even, probably, at times by
insects. Every gardener recognises that really good
cultivation (1.e. the provision of the conditions which
secure good health) renders attack by mildew, e.g.
on peas, far less likely to occur, while protection
from cold winds or sudden chills almost certainly
secures peaches and the like from the “curl ”’
disease. It might indeed be said that the best
preventive of disease is the maintenance of good
health.

39

Variegation

Brief reference must be made to one or two
diseases which are to be regarded at present, possibly
because little is actually known about them, as
constitutional, unavoidable (unless by rejection of
the plants likely to exhibit them), and incurable.

Variegation is to be regarded as a disease, for
it is due to absence of green colour from parts of
foliage and stems, and this results in a check to
food-making and a lessened vigour of growth, but
it is often regarded as desirable, and is preserved.
It is a transmissible disease also at times, for if, e.g.,
the variegated greenhouse Abutilon be grafted on
a green seedling, shoots from below the graft will
often be variegated.

The mottling of leaves (without the complete
suppression of green colour in the lighter portions)
forming the characteristic symptom of the “‘ mosaic ”
disease as it is called, seen in tobacco, tomatoes,
beans, sometimes in Pelargoniums, and probably also
in figs, is similarly transmissible and, though possibly
of bacterial origin, seems possibly constitutional and
more or less independent of cultural conditions. It,
too, reduces the food-making efficiency of the foliage.

The leaf-curl disease of potatoes is sometimes
apparently constitutional. Six diseases of potato
are characterised by leaf-curl or leaf-roll, and of
these two have not been traced to parasitic origin.
One called “curly dwarf” is characterised by
shortened internodes, brittle stems, small curled

40

Potato Leaf-curl

leaves, and small yield. The other, which is intensi-
fied by climatic conditions, is marked by the upward
inward rolling of the usually small discoloured
leaves, shorter, more erect haulms, small flowers and
berries and small yield of tubers which do not decay
when planted. In both cases tubers from affected
plants produce diseased offspring. Leaf-curl some-
what similar to the first but with less dwarfing is
constitutional in certain races of tomato, and occurs
in beets, though in the latter it may be of parasitic
origin.

The nettle-leaf disease of black currants, in which
the foliage is narrower and more divided than is
normally the case, and the yield small or none, has
not so far been certainly traced to any other than
“ constitutional” causes. Red currants and goose-
berries are sometimes similarly affected.

The doubling of flowers, which is generally a
constitutional character, may also be looked upon
as a diseased condition, since it generally reduces or
destroys the power of the plant to set seed. It is
often regarded as an added beauty and preserved in
the garden, and is of course in no way detrimental
to the well-being of the individual although it is of
the race. For some reason not at all clear double-
flowered plants are at times more delicate than the
corresponding single-flowered type, and the degree
of development of the doubling is dependent toa
large extent on the available food substances.

41

CHAPTER III
THE NATURE OF FUNGUS ATTACKS

Piants find enemies ready to prey upon them both
in the vegetable and in the animal kingdom. Among
the former fungi and bacteria are the most numerous
and important, although a few colourless flowering
plants such as dodder, broomrape, and toothwort
occasionally find their way into the garden, and prey
upon the garden plants. The enemies among the
latter are dealt with in later chapters.

The principal characteristics of fungi are : (1) they
are not green, i.e. they contain none of the green
colouring matter possessed by ordinary plants ;
(2) their bodies consist usually of slender branching
threads called a mycelium, but may be reduced to
much smaller proportions, indeed to a minute cell
less than a thousandth of an inch in diameter ;
(3) they are propagated by minute pieces, called
spores, pinched off the mycelium or formed inside
special cases.

Bacteria are, broadly speaking, similar to the

42

Fungi

fungi, but generally increase by splitting in two at
maturity.

The absence of green colouring matter enforces
life either as parasites preying upon living plants or
animals, or as saprophytes, that is, feeders upon
decaying animal or vegetable matter. The latter
mode of life, interesting as it is, and important as it
is from an economic point of view, does not concern
us here, nor do the fungi and bacteria parasitic
upon animals. There are many, however, which
subsist upon plants and do more or less harm to
them.

Each of these parasitic fungi is, as a rule, to which
there are several exceptions, restricted to a small
range of “hosts,” as the plants upon which they prey
are called. That is to say, for example, a mildew
attacking roses will not also attack peas or goose-
berries. The exceptions are generally fungi which
attack plants already in ill-health, and some of
them are capable of living on decaying matter as
well.

The spores are so minute that they are readily
carried from place to place by the wind, or on the
feet of birds, or by insects, and they are, no doubt,
distributed widely by these agencies. Diseased
plants themselves may carry them from one garden
to another, or from a garden to an exhibition, where
some may be left upon a neighbouring exhibit.
(How often have we seen “ rusted ” chrysanthemum

43

Spore Distribution

publicly exhibited. It would be a good thing if
judges rigidly disqualified such diseased plants.)
Refuse and manure heaps may harbour them, or
packages which have been in contact with diseased
plants may spread the spores. Seed (in the
gardener’s, less often in the botanist’s, sense) may
contain them ; or the fungus itself, or its spores may
adhere to the seeds, and so on. Even particles of
soil, as, e.g., from a “club ’”’-stricken cabbage-patch,
may spread the fungus to other and hitherto healthy
gardens.

Perhaps to follow the history of a familiar fungus
is the best way of gaining a clear idea of its way of
life. The rose mildew is perhaps as familiar as any,
at any rate to country dwellers. The mealy white
covering which betokens the attack on shoots and
leaves, and later the felted mass of mycelium which
encircles the young shoots or forms wide patches
upon them, are far too common for the pleasure of
the gardener. This felt is so conspicuous because
the mycelium is formed wholly outside the plant
(the case only in the mildews), merely sending
minute suckers into its host to absorb its sap. This
robbery results in the shrivelling of the cells attacked
in consequence of the loss, and the leaves fail to
expand properly, so that food-making is interfered
with. Some cells may actually be killed outright,
and brown patches result. The mycelium has
grown from a spore which germinated where it fell

44

“Cad MNVO ATGVA WHS asoy “LOdG MOWIG AC GANOWLY Ava] Aso

WVLLV AVA GNV LOOHY ASOY

isa, Au UNV AVeltp asOyy

Rose Mildew

upon a leaf or shoot, when moisture, temperature,
and air-supply were suitable. It threw out a
minute thread from which, if it has reached a leaf
which the fungus is capable of attacking, suckers
are soon thrust out into the leaf-tissues in search
of food.

Feeding on the sap it absorbs, the fungus gradu-
ally and quickly spreads all round the spot first
attacked and throws up a number of short upright
threads from the tips of which spores are pinched
off in great numbers. These give the mealy appear-
ance already alluded to. The spores are easily
carried to other spots, and if conditions are favour-
able spread the disease.

These summer spores are produced in great
‘numbers as the parasite grows, but each lives
only a short time. Later in the season, when the
mycelium has formed a felt, another form of
spore is produced inside cases with resistant walls,
and these remain over winter, burst in spring, and
liberate the spores to renew the disease another
season. The felted mycelium may also remain alive
and form a centre of infection for another year.

The fungus is the cause of the disease: the host
suffers from actual loss of food of which the fungus
robs it, and more still from the crippling of the
foliage which prevents it from performing its
functions of food-making, etc., to the fullest extent,
But the host has, under certain circumstances, the

45

Disease Resistance

power of resisting the attack. Careful observation
will show that

(1) Old leaves are very rarely attacked.

(2) Some varieties are almost or quite immune
from attack though their neighbours readily
fall victims.

(3) A variety may be attacked in one garden and
escape in another.

Possibly the thick cuticle of the older leaves
preserves them from penetration by the fungus, but
what exactly renders one variety immune and
another prone to attack is not yet clear. Certainly
the glossy-leaved Wichuraiana hybrids are “ cleaner ”’
than many hybrid teas, but it is probably not merely
a mechanical obstruction that preserves them.
Plants in a draught, or which have been subjected
to drought, or which are growing in a close, ill-
ventilated spot, are usually the first to be attacked.
Is it because some substance is formed in them under
these conditions which attracts the fungus ? or is it
because some substance is not produced then which
under better conditions prevents the fungus attack ?
Is it because the fungus spores themselves require
to be subjected to a low temperature before they will
germinate ? or is it a combination of any or all of
these ?

It is a remarkable, and probably significant thing,
that in the moist warm districts of the tropics
mildews are unknown, as they are, so far as I know,

46

Peach Curl

in stoves in this country. It is certain, tov, that
conditions which keep roses growing without a
check render attacks of mildew less likely.

A remarkable instance of the dependence of
fungus attack upon external conditions, unfavour-
able to the host but favourable to the parasite, is
afforded by the leaf-curl disease of the peach,
practically unknown when the plants are grown
under glass or in sheltered situations, frequent and
disastrous in plants exposed to cold winds and other
retarding influences. Damping-off in seedlings,
again, one might be tempted, but for the manner
in which the trouble spreads, to attribute solely to
close seeding and close, damp conditions, yet a
fungus is always involved too.

We have thus more than one cause contributing
to the development of the disease—the fungus itself,
the constitution of the host-plant, and the nature
of the environment which influences either the host
or the fungus or both.

The mycelium of the parasite is usually not
external asit isin the mildews. It generally burrows
about inside its host in its search for food, creeping
between the cells and sending suckers into them, or
passing through them. It may produce a poison
which actually kills the cells it comes in contact with
(even some little distance ahead of the mycelium),
or grow without doing more harm than arises from
robbing the plant of some of its sap and diverting

47

Disease Symptoms

to its own ends what was intended for the nourish-
ment of its host. Curiously contorted growths are
often produced through the check to the development
of local parts induced by the parasite, or through
a curious effect such as is seen in cabbage roots
attacked by the club-root organism, where much
more extensive growths than usual are induced.
These dead spots, contortions, and swellings afford
symptoms by which diseases may be recognised, and
will be referred to again.

When the mycelium of the parasite is internal,
as a rule a number of threads are thrust out of the
host to form spores for the distribution of the fungus,
or fruits containing the spores are produced on the
surface of the host. The spore-bearing threads or
fruits are usually massed in sufficient numbers, and
have some characteristic colour, which enables a
gardener, with the aid of a pocket-lens such as all
good gardeners carry, to use them for the recognition
of a disease.

To make out the structure of the spores them-
selves, and to identify the fungus with certainty,
requires the aid of a compound microscope and
considerable training, and are usually impossible
for the gardener. These things are necessary to the
proper understanding of the disease, but many
common attacks may be recognised readily without
this kind of examination. .

Some fungus attacks are confined wholly or

48

Sclerotia

almost wholly to the parts of the plant below ground,
such, for example, as wart disease of potatoes,
club-root of cabbages, and the like, and may become
evident only when the plant is lifted. On the other
hand, destruction or damage to the absorbing roots
may occur and wilting of foliage follow. The spores
of the fungi concerned are present in the soil about
infected plants, and are carried from place to place
not only on or in infected plants, but with the soil
itself. Little imagination is required to picture the
trouble likely to arise from conveying such soil on
plants during transplanting, on tools, boots, carts,
and the like, from infected to clean situations ; the
wind-borne dust may carry the spores too.

Certain fungi form masses of mycelium which
rest through ungenial seasons. Pieces as large as
peas or larger, generally black, occur inside the stem
of Dahlias or potatoes when attacked by the ‘‘Sclero-
tium disease.”” They are black outside and solid,
rather like wax to cut, and will withstand drying
and other conditions unsuitable for growth. Such
masses are called sclerotia, and the term “ Sclerotium
disease” is derived from their name. “ Fire”’ in
tulips is due to one of them. Curious sclerotia are
formed by the fungus which attacks the roots of
anemones and sends up brown cups in spring where
one looked for a brilliant display of blossom. The
whole root is permeated by the fungus, and the
sclerotium assumes the form of the root which the

49 E

Fungi in Winter

fungus has killed. ‘“ Mummy” apples and plums
are produced when these fruits are attacked by the
fungi which cause “brown rot,” the whole flesh
being filled by the mycelium, and they form resting
sclerotia. The ordinary mycelium itself may cease
to grow but still remain alive for some time as in
mushroom spawn such as is sold for making mush-
room beds. Myriads of spores are produced by the
mushroom on the gills of the edible fruit, but gardeners
have to depend upon the white thread-like mycelium
of the fungus for purposes of propagation. We have
many instances of this ‘‘ perennial mycelium ”
among fungi causing plant diseases. The rust of
mint, the smuts of Scillas and of Carnations,
are examples. Once attacked these plants are
affected year after year and annually produce a
crop of spores. In these cases their utility or
beauty are injured but their existence not materially
threatened. It is otherwise with the perennial
mycelium of certain fungi which attack trees, such as
Stereum purpureum, which produces silver-leaf, or
Nectria ditissima, which is associated with “‘ canker ”’
of fruit trees.

No means of reaching the mycelium of a fungus
inside a plant are known. Nothing at present
known which can be injected or made to pass into a
plant will kill the fungus without at the same time
damaging the plant itself. In the treatment of
plant-diseases induced by fungus attack the most

50

Forestall Disease

important thing to attend to is, therefore, the
prevention of attack. Not only is “ prevention
better than cure’’; it is often the only way to
avoid death.

Diseases due to fungi and bacteria are generally
characterised by the formation of spots of various
colours on the affected parts of the plant, these spots
being either masses of spores or fungus fruits, or
groups of dead or damaged cells; or by locally
increased growth ; or by the destruction of parts of
the plants ; in all cases accompanied by the causal
organism, either immediately or in the near neigh-
bourhood. The attack is dependent upon

(1) The presence of the fungus or its spores ;

(2) The plant being of a variety liable and in a
condition suitable to attack ;

(3) The conditions of moisture, air, and warmth,
etc., being suitable for the germination of
the spores and the growth of the fungus.

The attack starts in one or a few places and
progresses more or less rapidly according to the
nature and condition of the plant and its surround-
ings. The disease is very “catching,” and not only
the diseased plant but its immediate surroundings
are likely to be a source of infection to others if the
disease is allowed to continue long.

The sudden death of a plant without previous
symptoms of ill-health is not likely to point to fungus
attack asacause. Fungus attacks may appear to be

51

Disease Symptoms

sudden as, for instance, in the case of the too well-
known potato-blight, where a whole field will seem
to be smitten and dead within a few days. It is
true the fungus spreads rapidly and works quickly
when the conditions which induce the develop-
ment of thunderstorms prevail, but it has been
growing on the lower leaves of the plants earlier,
and has not been noticed because it has been
hidden.

Perhaps a word of caution in interpreting
symptoms should be given. When a fungus is
found growing on a dead leaf or a dead spot on the
leaf, it is not a certain sign that the fungus is the
cause of the death of the leaf or of the part of it.
The proof of the fungus being the cause is not a very
easy matter to establish. The spores of the fungus
in question must be obtained free from all mixture
with other spores, or indeed with other organisms ;
they must germinate upon and attack an otherwise
healthy plant kept from chance infection by any
other organism of any kind whatever ; this attack
must produce the same symptoms as were present in
the original attack; and finally the fungus must
fruit and prove its identity with that which was used
to infect.

Only when the fruits and spores of a fungus are
obtained can its identity be established.

We have already alluded to the fact that not all
the varieties of any one kind of plant are equally

52

Immunity

open to infection by a parasite which attacks one
variety of it. For example, the spores of a certain
mildew which attacks grasses will not attack a
grass ‘‘ A ”’ if they have been taken from mildew on
a grass ‘“‘C,” although spores from mildew on grass
“A” will readily attack the leaves of other plants
of the same variety. They will, however, attack
grass “‘B,” and spores produced by the mildew
growing on grass ‘‘B’”’ from the spores obtained
from grass “C” will attack grass “A.” This fact
seems to show that one and the same fungus may
behave differently according to the source from which
itis obtained, and it has been found possible to train
a fungus which usually lives on dead plants to
attack living ones! Further, one stage of a fungus
may grow on a living plant, and another slightly
different stage, only on the dead remains of the
plant. A fungus may enter a plant (generally
through a wound) and grow but fail to fruit until the
plant it has attacked is dead—such are the fungi
that produce silver leaf in plums and “ coral-spot ”’
on the dead shoots of currants.

A further remarkable phenomenon shared with
certain animal parasites is afforded by some of the
rust fungi. These fungi form a distinct group and
in their most highly developed forms produce a
variety of different spores during their life-history.
The early stage when present produces numerous
dust-like spores in minute circular cups with turned-

53

Alternate Hosts

back edges on the surface of living leaves. These
spores germinate, and later on produce spores of a
totally different kind, and frequently will not attack
the same kind of plant as that upon which they were
produced. Thus the spores produced by the fungus
Coleosporium Senecionis on the needles of the Scots
fir, germinate and attack, not that, but the groundsel
or the Cineraria and produce totally different
symptoms; Cronartium ribicolum grows in its cup
stage on Pinus Strobus, but forms its later spores on
the black currant; Puccinia Pringsheimiana has
its early cup stage on the gooseberry, its later on
the sedge; Puccinia Pruni lives first on the anemones,
later on the plum; and so on. The latest spores
formed on these second hosts usually rest, and after
their rest produce the cup-forming stage on the
first-mentioned host only, but an intermediate form
generally occurs produced on the second host which
attacks that host only. The best-known instance
is probably the red rust of wheat. In spring the
fungus, Puccinia graminis, forms whitish cups
(aecidia) on the leaves of Barberry. The yellowish
spores (aecidiospores) attack the wheat, and the
mycelium in summer forms reddish groups of spores
(uredospores) in small patches on the wheat leaves.
The uredospores germinate immediately and attack
other areas on the wheat leaves, so spreading the
infection. Towards autumn the mycelium which
has hitherto produced uredospores forms another
54

Rusts

kind of spore altogether, of a deep chestnut colour
and of different form (teleutospores), incapable of
immediate germination. The teleutospores remain
on the dead straw through the winter and then
germinate, forming there a few spores only which
cannot attack wheat but grow only on the Barberry,
recommencing the life-cycle.

These and other phenomena make the study of
diseases of plants produced by fungi very interesting,
but at the same time very difficult, and complicate
methods of control. For instance, the destruction
of all the black currants within a radius of two miles
of a plantation of Pinus Strobus would doubtless
protect that valuable tree from the blister-rust that
has proved so fatal to it where it has occurred, but
so many interests would be involved that such
measures are almost impracticable.

55

CHAPTER IV
TREATMENT OF FUNGUS ATTACKS

Meruops of dealing with fungus attacks fall mainly
into three groups according to the end they have
in view. Hither they aim at

(a) The protection of the plant against attack ; or

(b) Rendering conditions unsuitable forthe growth

and spread of the fungus; or

(c) The removal of the source of infection.

We have already dealt with the principal safe-
guard against disease in our first chapter, and need
only briefly mention the necessity for the mainten-
ance of proper cultural conditions and of adequate
and properly balanced supplies of earth-salts, water,
air, light, and heat. We may put the remaining
methods in numbered paragraphs to facilitate re-
ference, but this important recommendation applies
to all. In addition we have :

1. The selection of varieties resistant to or
immune from attack. This is possible in compara-
tively few cases at present, but research will show

56

Pruning

that such varieties already exist, or are attainable
in many more. :

2. Removal of dead foliage, dead shoots, and dead
plants from the neighbourhood of living ones.
These dead parts often harbour pests or permit an
entrance into the living parts by way of the dead.
The wood-pile and the rubbish heap should not be
near the garden.

3. Pruning away the diseased parts completely
as soon as seen, and immediate destruction of them
by burning.

4. Complete removal and immediate destruction
of diseased plants and of the soil about them by
burning. By no means let them reach the rubbish
heap. Even feeding pigs with diseased parts is apt
to be dangerous.

Weeds such as groundsel, sowthistle, shepherd’s
purse, charlock, chickweed, briars, and the wild
parents of our cultivated trees often harbour fungus
pests, and should be watched and promptly dealt
with.

5. Pruning and otherwise wounding plants in
cultural operations in such a way that the wounds
readily heal over. Protection of all wounds by
painting them over with lead paint, Stockholm or
gas tar, or a 24 per cent solution of lysol. This
painting does not assist healing but forms a barrier
to the entrance of fungi and bacteria.

6. Steeping seed and tubers suspected or known

57

Spraying

to be infected with fungus diseases or with fungus
spores, with the object of killing them. The princi-
pal substances used are hot water, copper sulphate,
formalin, and hydrogen peroxide. The hot water
and copper sulphate methods are used almost
entirely in treating farm seeds, and we need not
consider them further. Formalin is used in treating
both seeds and tubers, hydrogen peroxide in treating
seeds.

(a) Formalin Treatment.— A solution of 1 part
of formalin (=40 per cent solution of formaldehyde)
is made in 200-300 parts of water. The seeds or
tubers are steeped in this solution for two hours.

(b) Hydrogen Peroxide Treatment.—The seed is
steeped to two hours in the full strength hydrogen
peroxide (20 vols.) and rinsed in clean water. The
half strength (10 vols.) may be used. It is usually
convenient to dry the seed before sowing.

7. Dusting or spraying plants with a poisonous
substance so that spores, falling on the plant and
commencing to germinate, will come in contact with
it and perish. Sulphur and copper compounds are
generally most effective. The former are used
against mildews, as they tend to destroy the external
mycelium which these fungi form.

All sprays, whether dust or liquid, should be applied
in a state of very minute subdivision, and when the
sun is not bright ; an endeavour should be made to
cover all parts of the plant completely.

58

Sprays

(a) Sulphur-dusting.— Flowers of sulphur are
dusted over the affected parts, or those it is desired
to protect, by means of powder bellows specially
constructed for the purpose, or of a flour-dredger.

(0) Sulphur-fumigation Sulphur is placed in a
specially constructed vessel and heated so as to be
vaporised, but not burned ; the vapour is condensed
on the foliage, etc., and every part becomes covered
with a thin film of sulphur. A crude method of
effecting this has been in vogue, the sulphur being
heated on a hot iron plate, but there is great danger
of it bursting into flame, and the gas formed by burn-
ing sulphur is fatal to living plants.

Another method of applying sulphur is that of
making a paste of it in milk and painting the hot-
water pipes. The heat of the pipes probably causes
the sulphur to be very slowly oxidised and the
poisonous gas to be produced in sufficient quantities
to check fungi effectively.

(c) Liver of Sulphur, or potassium sulphide.—
Liver of sulphur is dissolved in water at the rate of
1 oz. to 3 gallons (or 1 oz. to 4 gallons, when tender
plants have to be sprayed). The solid material
should be kept from the air or it speedily deteriorates,
and care should be taken to obtain only the soluble
forms. Itis a useful fungicide, but stains white-lead
paint black.

(d) Copper Compounds. — Liquids containing
copper are used, for the most part, for spraying

59

Fungicides

plants open to attack by fungi which live inside the
plant, and enter through the pores in the leaves.
They are used for the purposes (1) of killing the
fruiting threads of the fungi as they emerge into the
air to form spores, and (2) of preventing the germina-
tion of spores which fall upon the leaf.

Care must be used in spraying with them when
parts of plants which are eaten are to be dealt with ;
e.g. spraying broad beans attacked by rust with a
copper fungicide would be perfectly safe, as only the
shelled immature seeds are to be eaten, but spraying
dwarf beans when the pods are formed will be
inadvisable.

Three mixtures containing copper are used for
the summer spraying of foliage, and one for winter
spraying of dormant trees only. They are respect-
ively Bordeaux mixture, soda- Bordeaux or Bur-
gundy mixture, ammoniacal copper carbonate, and
copper sulphate solution.

Great care must be exercised in preparing these
fungicides (which are better made at home), but if
the following directions are followed there need be
no difficulty.

Bordeaux Mixture-—Put 6 lbs. copper sulphate
(of 98 per cent purity) (called also blue stone or blue
vitriol), broken small or powdered, into a loosely
woven canvas bag and hang it the night before the
fungicide is to be used in a wooden tub containing
about 20 gallons of water. [An iron or galvanized

60

Fungicides
vessel must not be used.] Into another vessel put
4 Ibs. of good quicklime (unslaked lime) and slake
it by adding water, gradually at first until the
lime crumbles, then more quickly so as to form
a milk. Next morning, when the milk of lime is
cold [both liquids must be cold], strain it through
a coarse cloth so as to remove all lumps, into
the copper sulphate solution, stirring well mean-
while. When nearly all the milk of lime is used
allow the mixture to settle a little, then test the
clear liquid from the top by adding a drop to a
drop of potassium ferrocyanide on a white plate.
If no red colour is produced the mixture is fit for
use, but if a red colour is formed, more milk of lime
must be added until the clear liquid gives no red
colour with potassium ferrocyanide. When no red
colour is produced by this test, it shows that all the
copper is combined and the risk of burning the
foliage is reduced to a minimum. The mixture
should be of a blue colour if properly prepared, and
the fine powder to which the colour is due should
be slow in settling out. Make up to 40 gallons with
water, and make afresh whenever it is wanted.

This is the most generally useful and most tried

fungicide, and is in wide use in all civilised countries.

Soda-Bordeaux or Burgundy Mixture—Dissolve

10 Ibs. of copper sulphate in 25 gallons of water in

the way recommended above. Dissolve 114 lbs.

of washing soda in another 25 gallons. When both
61

Rotation

are cold mix thoroughly just before using. To test
this mixture use litmus-paper. If red litmus is
turned blue by it, add more copper sulphate; if
blue litmus is turned red, add more soda solution.
It should have no effect upon litmus-paper.

This is rather easier to make, and seems to be
almost as effective as Bordeaux mixture when used
for the same purposes, although it has not yet been
used to any great extent in this country.

Ammoniacal Copper Carbonate-——Make 5 oz. of
copper carbonate into a paste with a little water,
add strong ammonia (‘880) until the copper car-
bonate is just dissolved so as to form a deep blue
solution (about 3 pints will be required) ; dilute this
to 45 gallons with water. The stock solution may
be kept in a tightly stoppered bottle. This may be
used where Bordeaux mixture is likely to cause
defoliation, as with peaches against shot-hole.

Copper Sulphate Solution—One pound of copper
sulphate (98 per cent) is dissolved in 25 gallons of
water in a wooden vessel.

This solution must be used only in winter, while
the trees are dormant.

(e) Potassium permanganate diluted to a rose-
red colour is useful against some rust fungi such
as rose rust, hollyhock rust, carnation and Saxifrage
rust.

8. Rotation of crops and breaking up areas
occupied by one kind of crop. Modern methods of

62

Insects and Disease

growing one kind of crop over large areas have made
the spread of plant pests much more easy than it
formerly was, and something in the way of breaking
up these areas by interposing other crops will impose
a check to their spread. In the same way changing
the ground occupied by one crop in succeeding years
will render the attack of pests which lurk in the soil
more difficult.

9. Destruction of “hosts” of garden enemies. In
paragraph 4 above we advocated the destruction
of diseased weeds and the like, but it is as import-
ant to remove this chance of propagating disease-
producing fungi. Where possible the alternate host
of the rust fungi (where there is one) should be
destroyed. Hedge plants should differ from the
cultivated crops as much as possible.

10. The fruits of the large fungi which attack
timber and ornamental trees should be removed as
soon as they appear, so as to prevent the formation
and spread of the spores.

11. Certain insects, such as woolly aphis, are
concerned in the spread of certain plant diseases
and should be destroyed.

12. An acid condition of the soil encourages the
growth of certain fungi such as club-root, and should
be remedied by the application of quicklime at the
rate of 3-4 tons to the acre (3-1 bushel to the square
rod) spread over and forked in. It is, however,
better to avoid the need for this drastic dressing by

63

Legislation

smaller dressings calculated to avoid its necessity
(see Chapter IT.).

An opposite state of affairs encourages a few
bacterial diseases such as iris rhizome rot, and here
the admixture of superphosphate of lime at the rate
of 14-2 oz. to the square yard will be beneficial.

13. Of recent years legislation has been aimed
at the control of certain plant diseases, but while of
some value when carefully considered and efficiently
and intelligently administered, too much must not
be hoped from it. Legal enactments regarding
plant diseases are apt to leave too many loopholes
through which the fungus may escape and spread
for any great dependence to be placed upon it.
Nothing short of cessation of all commerce and
intercommunication is likely to stop the wide-
spreading of disease, and even that would fail to
stop its spread over narrower areas. Loyal observ-
ance of the enactments, together with personal
observation, intelligent cultivation, and prompt
application of remedial measures, are all requisite.

14. We close this chapter with a reiteration of
the advice to maintain good health by attention to
hygienic requirements, i.e. good treatment. Avoid
damp, close quarters; avoid draughts; avoid
acidity of soil; avoid over-manuring.

64

CHAPTER V
SYMPTOMS OF FUNGUS ATTACKS

AOER PsEUDOPLATANUS (Sycamore).

Foliage.—Black blotches on leaf-tissue caused
by Rhytisma. Collect and burn fallen leaves (2).1

ALMOND.

Stem.—Gummy excretion arising from crack
in bark of trunk or branches. Cut out and
burn affected parts, painting wounds (5).

Foliage.—Swollen, red, and blistered-looking
leaves, caused by attack of Exoascus deformans
= Peach Curl disease. Keep free from draughts.
Remove as soon as seen (3); spray with
Bordeaux or Burgundy mixture in February (7).

Roundish holes in foliage with a brown edge ;
or brown spots which subsequently drop out,
caused by Cercospora circumscissa. Spray
foliage and soil with Bordeaux or Burgundy
mixture (7).

1 Figures in thick type refer to a paragraph in Chapter IV.
where the remedial measure is described.

65 F

Symptoms

ANEMONE.

Rhizome.—Large hard, blackish masses of
mycelium replacing rhizomes, white within and
waxy to cut; producing brown cup-shaped
fruits in spring. Sclerotinia tuberosa. Dig up
and burn when fruits are seen.

Foliage.—Cluster cups (species of Aecidium,
often forms of Puccinia), forming spots on stalk
and blade. Affected plants are often taller
than normal.

ANTIRRHINUM.

Stem and Foliage—Pale brown or almost
white roundish or elliptical spots with minute
black dots upon them. Septoria antirrhini.
Spray with potassium sulphide or Bordeaux
mixture (7).

APPLE.

Root.—Large globular swellings about the
size of a golf ball (larger or smaller), generally
with a corrugated surface. Crown gall, due to
Bacillus tumefaciens. Not a serious disease in
this country. Cut off and burn affected roots
when planting.

Stem.—Areas eaten out, as it were, down to
the wood, the edges of the wound showing
attempts to heal which have failed ; in winter
having the round bright red fruits of the fungus
upon the dead healing tissue, in spring the
brownish mounds of fungus mycelium. Canker,

66

Youna APPLE SHOOTS ATTACKED BY AMERICAN BLIGHT.

APPLE SHOOTS ATTACKED BY CANKER.

Symptoms

due to Nectria ditissima. Cut out cankered
spots and paint wounds (5); attend well to
drainage and destroy woolly aphis (p. 122).
Other fungi produce canker ; treat in same way.

Young branches cracked, and with olive-
green areas upon them. Scab (see fruit, below).

Young branches cracked, twigs and spurs
dying, and bearing small grey mounds of fungus
mycelium and spores. Brown rot (see fruit,
below).

Foliage. — Dark branching mycelium on
leaves, followed by dead spots. Scab (see fruit,
below).

Rounded brown spots with a dark margin
and bearing minute black dots on upper surface.
Leaf-spot. Cladosporium herbarum. Attend to
health of tree ; spray with Bordeaux mixture (7).
Sphaeropsis malorum also forms similar spots
(and cankers on stem), and is treated similarly.

The whole leaf covered with a white powdery
mildew which also involves the shoot. The
mycelium subsequently forms a felted mat on
the shoot, which becomes very weak and often
dies. Conspicuous, owing to grey colour in
winter. Prune off and burn as soon as seen,
below the point of attack (3). Some varieties
are much more prone to attack than others,
eg. “ Bismarck,’ “‘ Lord Grosvenor,” ‘Irish
Peach.’ Caused by Podosphaera leucotricha.

67

Symptoms

Flower.—Pistil turns black as though affected
by frost, and a gummy exudation occurs about
base of styles. A bacterial disease for which
no cure is known ; probably carried by insects.

Whole flower turns brown and dies; flower
stalk generally shrivels and is covered by a
microscopic grey mould. Brown rot, see fruit
below. (Must not be confused with attack of
Apple Psylla, which produces somewhat similar
symptoms, but the flat green or yellowish insect
may be found in that attack embedded in a
gummy secretion; nor with Apple - blossom
weevil (p. 125).)

Fruit.—Dark green roundish spots on surface
of fruit (at first covered by the white cuticle
which the fungus lifts up and ruptures), which
finally become scurfy and surrounded by an
olive-green ring. In hard-fleshed apples like
“‘Cox’s Orange Pippin,” when the attack is
early, flesh of fruit often cracks badly as well.
Both shoot and leaf are attacked. Scab caused
by Fusicladium dendriticum (the final stage of
this fungus is called Venturia inaequalis and
occurs on fallen leaves). Prune out affected
shoots in winter (3), burn affected apples, spray
in winter with copper sulphate solution (7) and
just before buds burst and again after petals
have dropped, and also, if necessary, about the
end of June with Bordeaux mixture (7).

68

Stereum purpureum ON STEM OF AFPLE.

This is the fungus that causes silver-leaf disease.

APPLE ATTACKED BY ScaAB Disk ask

(Fusicludium deudviticum).

Symptoms

The fruit begins to decay prematurely, and
small grey heaps of fungus spores arranged
in “fairy rings” occur on the decaying spot.
Attack generally begins at a wound made
by an insect. The apple finally becomes a
“mummy,” and remains hanging on the tree
through winter. The shoots and flowers are
also attacked. Brown rot caused by Sclerotinia
fructigena (Monilia fructigena). Destroy
affected fruit by fire; prune and spray as for
** scab.”

Small brown circular spots on fruit at first
minute, gradually but slowly enlarging; at
first only skin deep. Probably caused by a
fungus ; no remedial measure known.

ARABIS.

White shining swollen convex patches on
the leaves as though sprinkled with whitewash
brush. White rust caused by Cystopus can-
didus.

Powdery greyish- white patches, on pale
finally dead brown spots. Rot mould caused
by Peronospora parasitica.

Spraying is hardly called for with this plant,
but affected foliage should be removed and
burned to destroy the resting spores of these
two disfiguring fungi.

Aster (MicHarLMas Daisy).
Foliage-—The whole plant covered with
69

Symptoms

powdery white mildew; leaves more or
less striated. Mildew caused by LHrysiphe
cichoracearum. Spraying with liver of sul-
phur (7).

AZALEA INDIOA.

Buds and Foliage.——Terminal bud or leaves
near tip of stem become swollen to many times
their normal size, pink, and subsequently
covered with a white bloom. Remove the
galls, which are caused by the fungus Hzo-
basidium japonicum, and burn before the white
bloom (the spores) is developed (3).

A similar fungus forms galls on Rhododen-
dron ferrugineum and other species (p. 95).

Bran, Broap.

Foliage. — Reddish-brown spots, showing
heaps of chestnut spores upon them under the
lens, on foliage. Rust caused by Uromyces
Fabae. Not as a rule serious early enough to
warrant spraying, but Bordeaux mixture or
potassium permanganate (7) may be used if
it is thought necessary. Burn rusted stems
instead of putting them on rubbish heap.

Brean, Dwarf AND RUNNER.

Foliage and Fruit. — Reddish round or
roundish depressed spots on fruit, brown
rounded spots on foliage and stems; in all
cases distinctly margined. Spot disease due
to Colletotrichum Lindemuthianum. Spray with

70

Symptoms
Bordeaux mixture (7). Burn affected fruits.
The seed from diseased fruits is apt to contain
the fungus.
BEET.

Foliage. — Small reddish-brown spots, on
which heaps of chestnut spores are to be seen
with a lens, scattered over the leaf surface.
Rust due to Uromyces Betae. Most prevalent
when soil is deficient in potash. Rarely worth
spraying for.

BERBERIS.

Foliage.—The yellow cups of one stage of
the rust of wheat, Puccinia graminis, occurs on
spots on the under surface of the leaves of some
species of Berberis. On the upper surface
of the leaf minute yellowish ‘ pycnidia”
occur.

Borecoue. See Cabbage.
Broccour. See Cabbage.
Brussets Sprouts. See Cabbage.
Buiuace. See Plum.

CABBAGE.

Seedlings —The stem becomes thin and
dies at about ground level, and the seedling
topples over. More prevalent under glass than
in the open. Thin seeding and early trans-
planting. Soil sterilisation. Caused by
Pythium De Baryanum. A minute fungus
called Olpidium Brassicae also attacks young

71

Symptoms
cabbages in damp, ill-drained places. Brown
spots are evident on the lower part of the stem,
which dies and decays.

Root.—Rootlets swollen in a spindle shape
much larger than normal; whole plant often
sickly-looking ; root subsequently rots and sets
free spores of the fungus, Plasmodiophora
Brassicae, to infect succeeding crops of same
family. Keep down weeds belonging to cabbage
family (9) ; practise rotation of crops (8); lime
the soil thoroughly (12). This is club-root
and should be distinguished from cabbage gall
weevil, which produces little lumps on the
stems, each containing a small grub.

Stem.—One-sided heads, or failure to form
heads, together with a dark ring seen in the
stem when cut across; leaves, except veins,
yellow (at margins at first); veins brown or
black. Slugs and caterpillars spread the cause
of this disease, a bacterium, Pseudomonas
campestris. Practise rotation (8); remove
affected leaves and destroy affected plants by
fire (3, 4). Seed should not be saved from
infected plants. [Black rot.]

Foliage.—White rust and rot mould; see
Arabis. Destroy affected parts (3, 4); spray
(young plants only) with Bordeaux mixture
or liver of sulphur (7); keep down weeds
(9).

72

‘WisLEY’ TRAP FOR 1HE TURNIP FLEA BEETLE.

6
/

ZZ

A SimpLE MovusE-TRAP FOR USE IN THE GARDEN.

1, Shows the tin buried in the soil. 2. The water in the
tin. 8. At the point shown by the arrow a hole is made in
the side of the tin to prevent the latter becoming full of
water. 4. Show a lump of grease fastened to the tilt on
the cross wire. 5, The cross wire, 6. The tilt fastened to
the latter, with small wire on the top of the tin. A hole
must be punched in the tin, or it will become full of water.

SENOUS SIAssMug, NO LOOY aATD

Symptoms

Pale green, later dry whitish or brown spots
caused by Mycosphaerella brassicicola. Same
measures as for white rust.

CALOEOLARIA.

Sudden wilting of plant. Cause doubtful,
but of fungus origin, probably a species of
Phytophthora which enters from the soil. Re-
move and destroy affected plants (4); practise
rotation (8); sterilise soil in which plant is
propagated ; lime soil.

CALLISTEPHUS HORTENSIS (CHINA ASTER).

Sudden wilting of plant due to Phytophthora.

Measures as with Calceolaria wilt.
CAMELLIA.

Foliage——Rounded or irregular blotches,
silvery white, with a distinct margin. Blotch
with minute black dots. Pestalozzia Guepini.
Remove and burn diseased leaves; sponge
with Bordeaux mixture.

CaRNATION.

Stem.—Yellow spot on deformed side of
stem, due to Fusarium sp. (? dianthi). Destroy
portions affected (3); practise rotation (8) ;
sterilise soil.

Foliage.—Rusty heaps of spores ; when these
fall, leaving light yellow spots. Rust. Uvromy-
ces caryophyllinus. Maintain dry atmosphere ;
destroy affected parts (3) ; spray with Bordeaux
mixture or liver of sulphur (7). Roundish

73

Symptoms
bright brown, then whitish spots (also on stem),
with dark fungus tufts arranged in concentric
circles. In bad cases most of leaf involved.
Black-mould or fairy-ring disease due to
Heterosporium echinulatum. Treatment as for —
rust. Select resistant varieties.

Spots yellowish, later with a rose or dull
violet margin; brownish-black dots upon the
spot. Leaf-spot due to Septoria Dianthi.
Treatment as for rust.

Grey or white powdery covering over foliage.
Mildew. Ozdium sp. Sprinkle with flowers of
sulphur, and maintain a dry atmosphere while
giving sufficient water in soil.

Flower.—Masses of violet-brown dust re-
placing pollen, so that centre of flower is
smutty. Ustilago violacea. Smut. Plant is in-
fected. while very young and is perennially
affected. Destroy (4).

CAULIFLOWER. See Cabbage.
CrLERIAO. See Celery.
CELERY.

Foliage—Dark dull green to brown or
yellowish-brown spots on foliage, densely covered
with black dots. Leaf-spot due to Septoria
Petroselint var. Apii. Destroy affected parts
by fire (3, 4); spray from May onwards with
Bordeaux mixture (7); use seed free from
infection (sterilise by hydrogen peroxide (6)).

74

CELERY FLy.
1. Celery fly. 2. Grub. 3. Chrysalis.

PEA AND BEAN WEEVILS.

land 2. Situnes crinitus, natural size and magnified,
3 and 4. Sitones lineatus, natural size and magnified,

WINTER Motus,
Male and two females.

CLick BEETLES AND WIREWORMS,

land 2. Agriotes lineatus. 3and4. A, obseurus. 5 and 6,
A, sputator, 7 and 8 Show wireworms natural size. 9.
Wireworm magnified, 10 and 11. Chrysalis.

Symptoms
CHERRY.

Root.—Large globular swellings on root=
Crown gall; see Apple.

Siem.—Gummy exudations through wounds
in stem or bark of twigs. Remove and burn
diseased branches, painting over all large
wounds.

Foliage-—Small round brown spots which
fall out, leaving a hole with a brown margin.
Shot-hole due to Cercospora circumscissa. Spray
with Bordeaux mixture (including soil surface).

Leaves wither, but remain hanging dead
on tree through winter. Collect and burn dead
foliage. Spray with Bordeaux mixture (7).

Leaves silvery or ashen. Silver leaf, see Plum.

Flower —Withering and browning of flowers
prematurely, and rotting of young fruits due to
Monilia fructigena. See treatment for Apple
brown-rot.

CHIONODOXA.

Flower —Brownish-violet masses of spores
in place of pollen. Smut, due to Ustilago
Vaillantii. Plants are attacked in the seedling
stage and never recover. Destroy them (4).
The same fungus attacks Scilla.

CHRYSANTHEMUM.

Foliage.—Greyish-white growth on leaves
and flower buds, the younger leaves being
deformed. Mildew due to Oidium chrysan-

~ 75

Symptoms

themi. Dust with flowers of sulphur or spray
with liver of sulphur (7). Spots appearing
brown on upper side of the leaf, and bearing on
lower side groups of chocolate-brown spores.
Rust. Puccinia chrysanthemi. Select resistant
varieties (1); propagate only from healthy stock;
spray with liver of sulphur as a preventive (7).

Dark brown rounded spots with a distinct
margin, on upper side of leaves, showing
minute black dots. Leaf-spot due to Septoria
chrysanthemi. Burn affected parts (3); spray
with Bordeaux mixture or liver of sulphur (7).

CINERARIA.

Foliage.—Greyish-white growth on leaves.
Mildew, due to Oidiuwm sp. Dust with sulphur
or spray with liver of sulphur (7).

Bright orange-yellow waxy patches on under
side of leaf, rarely visible above. Rust due
to Coleosporium Senecionis. Keep away from
related weeds such as groundsel and ragwort.
The alternate host is the Scots Pine.

CLEMATIS.

Stem.—Sudden wilting and dying of part or
whole of shoot. Due to the fungus Ascochyta
clematidina. Remove all dead or dying foliage
and shoots and spray with Bordeaux mixture
if spotted foliage be seen.

Foliage.—Greyish-white growth on leaves
and flowers. Mildew, due to Oidium sp. Dust

76

Symptoms

with flowers of sulphur or spray with liver of
sulphur (7).
CRATAEGUS.

Foliage—Leaves (and sometimes fruits)
swollen and bearing orange spots upon which
tufts of cup-like growths, at first flask-shaped,
later cylindrical, containing yellow spores,
occur. Rust due to Gymnosporangium clavarii-
forme, which has Juniper as alternate host.

Greyish-white growth on leaves and shoots,
which are somewhat dwarfed. Mildew due to
Podosphaera Oxyacanthae.

Yellow spots on upper surface of leaves, due
to Pleospora Oxyacanthae. These are not suffi-
ciently serious to call for remedy.

CRrEss.

Stem.—The lower part of stem at ground-
level dies and the seedlings topple over. Thin
seeding, ventilation and soil sterilisation are
the best preventive measures. Caused by
Pythium De Baryanum.

CUCUMBER.

Stem.—The lower part becomes “‘ cankered ”
and the upper part wilts. Mycosphaerella
citrullina. Destroy plants and avoid use of
soil again for cucumbers or melons.

Foliage—Whitish growths on leaf surface.
Mildew due to Erysiphe cichoracearum. Dust
with flowers of sulphur (7).

77

Symptoms

Small round dirty-white margined spots, or
larger grey spots in leaves. Leaf-spot, due to
Cercospora Melonis. Ventilate houses so as to
get “hard” foliage ; spray with liver of sulphur
or Bordeaux mixture (7).

Fruit—Dark depressed spots on rind of
fruit, later becoming black and cracking, and
sometimes with gummy exudation; fre-
quently large. Flesh of fruit below spot
golden or tawny. Scab, due to Cladosporium
Scabies.

Circular brown dry spots on rind. Due to
Gloeosporium orbiculare.

A bacterial disease sometimes causes rot of
fruit (and of foliage). The bacteria are easily
carried by insects.

Spraying is rarely effective with these diseases.
Clean cultivation, destruction of affected parts,
and good ventilation are the best preventives.

CURRANT.

Stem.—Shoots die back and bear bright
coral-red fruits of the fungus Nectria cinna-
barina upon them. The fungus enters through
dead wood ; prune out all such.

DadLiA.

Stem.—Death of lower part of stem, which
bears a grey mould, and subsequently develops
resting bodies of fungus mycelium as large as
peas or larger, often within the stem. Sclero-

78

Symptoms

tium disease caused by Sclerotinia Sclerotiorum,
for which there is no cure: burn affected
plants.

Damson. See Plum.
DELPHINIUM.

Foliage —Whitish growth on leaves, which
may become somewhat deformed. Mildew due
to Erysiphe polygoni. Dust with flowers of
sulphur or spray with liver of sulphur (7).
Many weeds are attacked by this fungus.

Diantuus. See Carnation and Sweet William.
Erica.

Fic.

Foliage.—Leaves and terminal part of shoot
covered with whitish powdery growth. Mildew
due to Oidiwm sp. Dust with flowers of sulphur.

Stem.—Cracks in bark and wood which fail
to heal, gradually girdling stem, which is finally
killed. Canker due to Libertella ulcerata. Cut
canker spots completely out, and paint these
and other wounds. Disinfect knife.

Fruit.—vVelvety grey patches at apex of
fruit, the tissues rotting and being reduced to
a pulpy mass. Grey-mould due to Botrytis
cinerea. Burn infected fruit.

Bitter rot due to Gloeosporium fructigenum
sometimes attacks figs; treatment, see Apple
brown rot.

A “mosaic ”’ disease of the foliage in which

79

Symptoms
light yellowish patches appear in the leaves
is probably of bacterial origin but awaits inves-
tigation.

GoosEBERRY.

Stem.—Shoots die, the foliage withering ;
tufts of grey fungus spores appear on dead or
dying parts. Die back due to Botrytis sp.
Prune out. Keep bushes in healthy growth by
manuring.

Stem, Foliage, and Fruit.—Greyish white
powdery mildew on stem, foliage, and fruit,
later turning dark brown, and bearing minute
deep brown globular fruits; forming a brown
felt on stem generally near tip. Growth
stunted. American Gooseberry mildew —
Sphaerotheca Mors-uvae. Cut off all tips of
shoots of affected plantation in early autumn,
and burnthem. Pick and burn affected berries.
Spray with liver of sulphur (half summer
strength for tender varieties).

Foliage.—Greyish powdery growth on leaves,
which are usually only slightly affected, gener-
ally not attacking stems or fruit. Not forming
a felt nor becoming dark brown. European
Gooseberry mildew—WMicrosphaera Grossulariae.
Spray with soda-Bordeaux mixture (7).

Yellow spots on one side of leaf, yellow-
bordered red spot on other, bearing longish
cups with white fringed margin filled with

80

Symptoms
orange spores. Gooseberry rust — Puccinia
Pringsheimiana, having as its alternate host
sedges which should be kept down in neighbour-
hood of gooseberries.

Grape. See Vine.
HawrtHorn. See Crataegus.
HELLEBORUS.

Foliage —Dark blotches somewhat rounded
in form, marked with indistinct rings. Leaf-
blotch due to Coniothyriwm concentricum. Pick
off diseased leaves and spray remainder with
liver of sulphur (7).

HoLLyHOocK.

Foliage.—Slightly discoloured spots on upper
surface, small, at first red-brown, later darker,
raised spots below. Rust due to Puccinia
malvacearum. No alternate host. Raise fresh
stock every year. Destroy seedlings found at-
tacked (the disease is apt to be conveyed in the
seed), and spray with potassium permanganate.

HYAcINTH.

Foliage and Bulb.—Veins of leaves and bulb
yellow, due to presence of a yellow bacterium,
Bacterium Hyacinth. Burn affected bulbs.

IRIs.

Rhizome.—The rhizome and lower part of
leaves become soft and rot away, the foliage
brown. Due toa bacterium which is encouraged
by lime in the soil. Treat soil with super-

81 ce

Symptoms
phosphate of lime after removing decaying
portions. Most prevalent when plants have
been subject to frost, or other severe check.

Foliage.—Large or small dark spots with a
yellowish or brown border, the dark portions
being velvety with the spores of the fungus
Heterosporium gracile. Remove all dead and
dying leaves thoroughly in autumn, and treat
the soil surface liberally with slaked lime.

Bulb.—Black crust-like patches on outer
bulb scales of Iris reticulata and its allies formed
by the fungus Mystrosporium adustum. Soak
bulbs in formalin (6). Plant such bulbs apart
from healthy ones.

JUNIPER. _

Stem.—Long woody swellings with fissured
bark through which the fungus emerges in soft
orange club-shaped masses, often forked and
variously curved. Juniper-rust due to Gym-
nosporangium clavariiforme and G. juniperinum.
The former has for its alternate host the leaves
and fruits of Crataegus (qg.v.); the latter the
Mountain Ash. The galls may be cut out and
burned.

Kouu-rasi. See Cabbage.
Larou.

Stem.—Wounds in the stem which exude
resin, and which fail to heal in spite of repeated
attempts. Larch canker due to the attack of

82

Symptoms

Peziza Willkommii. Plant larch in suitable
positions, well drained and not subject to spring
frosts. Avoid planting very large breadths of
larch only. Some species of Lariz, eg. L.
leptolepis, are more resistant than the common
larch, DL. europaea.

Latuyrus. See Sweet Pea.

LAUREL.

Foliage and Young Shoot.—Greyish-white
mould on the foliage, especially young foliage.
Mildew due to Sphaerotheca pannosa. Dust
plants with flowers of sulphur or spray with
liver of sulphur (7).

LAVATERA TRIMESTRIS.

Stem and Foliage.—Yellowish-brown rounded
spots on leaves, long spots on stems with a
darker margin. Due to Colletotrichum mal-
vacearum. Destroy affected plants as soon as
seen, and spray remainder with Bordeaux
mixture or liver of sulphur (7). The disease is
liable to be carried in the seed. The same
fungus attacks and kills hollyhocks in America.

LETTUCE.

Drop disease. The whole plant withers.
Attacked by fungus (Botrytis sp.) at base of
stem. Measures, see below.

Foliage-—Yellowish spots on foliage, with
white velvety fungus upon them on under side.
Leaf subsequently rots. Rot mould due to

83

Symptoms
Bremia Lactucae. Allow ample space ; remove
completely and burn affected plants and all old
leaves from beds, etc. Sowthistle and some
other weeds are also liable to attack by this
fungus.

Liny.

Foliage and Stem.—Brown spots on leaves
and buds which, with the stem, subsequently
die and dry up, while the flowers are distorted.
Due to Botrytis cinerea. Lime (mortar rubble
or chalk) should be mixed with the soil for
those lilies that do not dislike lime, especially in
the upper three or four inches, and the plants
grown in airy places not exposed to strong cold
draughts or late frosts. Dusting the bulbs with
sulphur is reported to have been beneficial.

LYoENIS.

Foliage.—Yellow blotches on foliage bearing
groups of chestnut spores often in concentric
rings. Rust due to Puccinia lychnidearum.
Not usually serious enough to spray for.

Flower.—Pollen replaced by purplish-violet
fungus spores which escape and discolour the
middle of the flower. Smut due to Ustilago
violacea. Destroy the plant, as the fungus is
perennial from the seedling stage.

Matva.

Various species are attacked by Hollyhock

rust. See Hollyhock.

84

Symptoms
MELon.

Stem.—Canker, see Cucumber.

Foliage. — Leaf-spot due to Cercospora
Melonis and a bacterial disease (which also
affects the fruit). See Cucumber.

MIGNONETTE.

Foliage. — Dusky brown indeterminate
patches on leaves, under lens appearing velvety.
Due to Cercospora Resedae. Most common in
damp soil lacking lime. Spray with Bordeaux
mixture or liver of sulphur (7).

Mint.

Foliage.—Leaves become yellowish and sickly-
looking, and bear on lower side (and often on
rhizomes, too), cup-shaped receptacles contain-
ing spores in spring, followed in summer by
small patches of chestnut-brown spores. Rust
due to Puccinia Menthae. Perennial in tissues,
therefore destroy affected plant completely.
Spray remainder with potassium perman-

ganate.
MuLuern. See Verbascum.
Mustarp.
Stem.—Damping off. See Cress.
NARCISSUS.

Foliage.—Dies prematurely near tip. Leaf
spot due to Ramularia Vallisumbrae. Destroy
diseased tissue. Jf occurring in second season
spray with Bordeaux mixture (7).

85

Symptoms

NrotTaRiIne. See Peach.
NYMPHAEA.

Foliage.—Holes with decaying tissues around
them. Ramularia nymphaearum. Remove
diseased leaves, and maintain stream of slowly
running water.

Oak.

Stem.—Several bracket-like fungus fruits
appear on stems of oak, when the fungi them-
selves are growing in and causing the decay of
the wood. These fruits should be cut away
and burned as soon as seen.

Foliage—Leaves and young shoots covered
with powdery white fungus growth. Mildew
due to Oidiwm sp. No remedy can be effec-
tively applied.

ONION.

Foliage.—Greyish-lilac tufts on foliage, some-
times entirely covering it. Onion mould, Pero-
nospora Schleident. Sow onions in autumn;
avoid damp sites; spray with Bordeaux mixture
(7); destroy all dead foliage by fire (resting spores
are found in diseased leaves).

Bulb.—Minute black hard bodies about the
neck of the bulb, the tissues of which are
softened and decay gradually spreads, due to
Mucor subtilissimus. Avoid using nitrate of
soda or other manure tending to sappy growth ;
dry off bulbs before storing.

86

Symptoms
Prony.

Foliage.—Leaves become spotted with brown
or turn wholly brown, or base of stalk becomes
brown and leaf flags; spots covered with grey
fungus, due to Botrytis Paeoniae. Small black,
hard, resting bodies about size of mustard seed
form on lower part of stalk or in soil. Remove
all diseased foliage; spray with Bordeaux
mixture or soda-Bordeaux (7).

Pans.

Foliage—Black spots are frequently de-
veloped on foliage of palms of various kinds due
to fungi (more than one species being involved).
The destruction of dead leaves and the removalof
affected parts are the best modes of treatment.

Pansy. See Viola.
Pars Ley (see also Parsnip).

Foliage Small brown spots on foliage on
which minute black dots occur, due to Septoria
Petroselini, possibly identical with the fungus
which attacks celery (qg.v.). Not generally
troublesome ; but if it should prove so, spray
with liver of sulphur (7).

Parsnip. :

Foliage—White mouldy patches on under
side of leaf, which turns brown in patches.
Due to Plasmopara nivea. The fungus also
attacks the root and forms rusty patches upon
it. If outbreak spreads, spraying with Bordeaux

87

Symptoms
mixture may be resorted to (7). Burn diseased
tissues, which may contain resting spores.

Pea (Culinary).

Root.—Chestnut brown patches on root
which subsequently dies, foliage turns yellow,
and buds drop or shrivel up. Due to Thielavia
basicola. See that drainage is thoroughly
efficient. Manure with potash manures.

Stem.—Brown stripes or streaks in stem,
brown (at first water-soaked) spots in leaves.
Bacterial disease encouraged by hot conditions
and spread by diseased seeds. No cure known.
Diseased seeds have water-soaked (when young)
or brown areas in the cotyledons.

Lower part of stem shows brownish ring
when cut, foliage wilts and turns yellow, due
to a species of Fusarium (F. vasinfectum 2).
Avoid planting on same ground next season.
Burn diseased plants.

Foliage.—Whitish powdery patches on foliage
due to mildew, Erysiphe polygoni. Most abund-
ant on late peas. See that soil is moist, and
avoid hot, dry places ; sow late peas in trenches.

Yellow spots on foliage, later followed by
greyish tufts of a fungus, due to Botrytis cinerea.
Most common in wet places,

Pods.—Round yellowish spots with a brown
margin, sometimes also on leaves. The centre
of the spot is occupied by brown fungus fruits.

88

Symptoms
Due to Ascochyia Pisi. Spray with Bordeaux
mixture or soda-Bordeaux.
PEACH AND NECTARINE.

Gumming, leaf-curl, and shot -hole, see
Almond. Silver-leaf, see Plum.

Foliage—Small yellowish spots on upper
surface, chestnut-brown heaps of spores below
freely scattered over leaf. Rust due to Puccinia
Pruni. Spray with Bordeaux mixture.

Fruit.—Whitish depressed spots on mature
fruit, surrounded by a blackened margin, due
to Gloeosporium fructigenum. Spray with liver
of sulphur or Bordeaux mixture. Burn affected
fruit.

Small round, at first greenish, then brownish
or olive spots on ripe fruit; the spots finally
run together and form a brown crust ; the fruit
cracks and decays. Scab due to Cladosporium
carpophilum. Spray before ripening of fruit
with Bordeaux mixture.

Greyish powdery growth over leaf and fruit,
often affecting considerable area of fruit surface.
Mildew. Dust with flowers of sulphur or spray
with liver of sulphur.

N.B.—Ammoniacal copper carbonate may
be used in all cases where Bordeaux mixture is
recommended for spraying peaches or nectarines
with less likelihood of damage to foliage.
See No. 7 (p. 62).

89

Symptoms
PEar.

Foliage. — Leaves distorted with blisters,
hollow below, the interior of the hollow being
whitish. Due to Hzoascus bullatus (not to be
confused with pear-leaf blister mite (p. 114)).
Spray with Bordeaux mixture (7).

Fruit.—See Apple. Scab in the case of the
pear is due to Venturia pirina (= Fusicladium
pirinum). Treatment as for apple scab.

[Note.—Foliage, especially of soft shoots,
turns suddenly brown, although hitherto in
apparently vigorous health ; black sticky fluid
exudes from bark. Fire-blight, an American
disease, for which watch should be kept, due
to Bacillus amylovorus. Carried by insects.
Burn all infected shoots and disinfect knife
used in pruning, before and after each
cut.]

PELARGONIUM.

Stem becomes blackened and decays ; leaves
turn yellow; pale spots, sometimes flesh-
coloured, appear on blackened portion of stem.
Stem-rot described by Dr. Cooke as due to
Fusarium Pelargonii. Destroy plants.

[Grey mould (Botrytis cinerea) often appears
on dying foliage and shoots of Pelargoniums.
A drier atmosphere and less close conditions
should be maintained, and all decaying leaves,
etc., burned.]

90

A Tent oF Lackey Motu CaTERPILLARS.

These do considerable damage to Apple and Plum Trees.

PEARS CRACKING DUE TO PEAR ScaB Funcus.

THE PEAR MIDGE AT VARIOUS STAGES.

1. Fully-developed fly. 2. Grub taken from a fruit. 3. Deformed fruit.
4, Grubs inside the fruit. 5. A perfect fruit.

Symptoms
PERIWINKLE. See Vinca.
Puasrouus. See Bean, Dwarf, and Runner.
PINE.

Foliage and Shoots.—White cups, torn at the
mouth, filled with orange spores scattered on
foliage, those on young shoots larger, crowded
and with torn, spreading mouth. Blister rust
due to Coleosporium Senecionis, having its
alternate host on groundsel and on Cineraria
(q.v.).

A somewhat similar rust on Pinus Strobus
(Weymouth Pine) (and attacking also other
pines with their needles in groups of fives) has
as its alternate host the black currant. It has
proved very destructive to the Weymouth Pine,
and where attempts are made to grow this
species the black currant should be exterminated.
Due to Cronartium ribicolum.

Pum.

Root.—Crown gall. See Apple.

Stem.—Shoots bear small black fruits of the
fungus embedded in the bark; later they die.
The wood is discoloured. Cut out and burn
all dead and dying shoots and branches. Due
to Cytospora sp. Also attacks cherries and
other kinds of fruit trees.

Foliage.— Leaf becomes pallid and shiny
as though varnished. Upper skin easily
separates from leaf-tissues below it. Branch

91

Symptoms

fails to fruit and finally dies. Wood becomes
discoloured, starting at a wound. Silver-leaf,
due to Stereum purpureum, which fruits only on
the wood which it has killed. Cut out and burn
all affected branches below the point at which
the wood is discoloured. Keep all dead wood
out of trees. Paint over all wounds (p. 57).
The fungus enters only by wounds. Attacks
various trees, especially “‘ stone fruits.”

Under side of leaf sprinkled with chestnut
brown heaps of spores, darker in the later
stages; whole leaf yellowish. Rust due to
Puccinia Pruni, which has as alternate host
Anemone coronaria (see Anemone). Remove
anemones from neighbourhood of plums. Spray
with Bordeaux mixture in June and July
(7).

Fruit—yYoung fruits grow very rapidly,
globose at first, but becoming elongated and
curved, up to two inches long by end of June ;
yellowish or reddish at first but becoming grey,
then black, finally falling. Probably spraying
with Bordeaux mixture (7) as soon as petals
fall would check the disease, which is called
“pocket plums ”’ and is due to Exoascus Pruni.

For brown rot see Apple. The attack on the
stem is more frequent than in the apple, and
particular attention should be paid to pruning
out the branches and spurs which show the

92

Symptoms
greyish-brown hard resting bodies of the fungus
through cracks in the bark, especially in spring.

Poityantrsus. See Primrose.
PopLaR.

Various spot-forming fungi occur on poplar
leaves, e.g. Septoria Populi (small round whitish
spots with greyish margin edged with brown),
Marssonia Populi.

Two rusts, Melampsora aecidioides and M.
populina, occur on poplar leaves, the former
forming yellowish groups of spores closely
scattered over the lower surface, the latter
brown ones or later blackish ones covered by
a crust, also on the lower surface.

Blisters on leaves, convex above, concave and
golden yellow below, attacking also catkins of
poplar and aspen. Due to Taphrina aurea.

Poraro.

Tuber.—Brown discoloration just beneath
skin. Blight. Phytophthora infestans, see
foliage.

Oval or round scurfy spots on skin. Brown
scab due to bacterium, Actinomyces chromo-
genus. Steep seed tubers in formalin, 1 part
to 200 water, for 2 hrs. before sprouting.

Deep scabs, dark green at first, generally
most numerous near “nose” end. Canker due
to Spongospora subterranea. Avoid planting on
same soil in next season.

93

Symptoms

Wart-like outgrowths, white, green or
blackish. Wart disease due to Synchytrium
endobioticum. Plant only immune varieties.
Notify Ministry of Agriculture.

Decay in store, brown depressed patches
with patches of white fungus thereon. Winter
rot, due to Fusarium Solani. Ventilate clamp
thoroughly.

Never plant diseased tubers.

Stem.— Wilts and turns black at base,
especially in vascular bundles. Bacillus solana-
cearum. Do not use tubers for seed. Remove
plant completely.

Foliage.—Black spots rapidly extending in
damp summer weather. Grey below. Blight
due to Phytophthora infestans. Spray before
outbreak with Bordeaux or Burgundy mix-
ture (7).

PRIMROSE.

Foliage with yellowish patches on upper and
under side, bearing tufts of fungus threads, due
to Ramularia Primulae. Spray with Bordeaux
mixture.

PRIMULA.

Few fungi attack species of Primula in this
country, but P. megaseaefolia is often attacked
by a fungus which produces brown spots on the
leaves. Spray with potassium sulphide or
Bordeaux mixture.

94

“ASVASI( LAVAA AM AANOVELV SHOLVLOG

Cop 7 OK] te soy)
Poway NO SOONG p bsOTT SONVUO

LU At NVA]

Symptoms

RaDIsH.

Subject to same fungus attacks as Cabbage

(p. 71).
RASPBERRY.

Stem.—Pallid patches on bark bearing min-
ute black fungus fruits, due to Ascochyta sp.,
ete. Remove diseased canes. Spray in August
with Bordeaux mixture.

Foliage. — Small yellow’ spots thickly
sprinkled over lower surface, followed by
tufts of dark spores, due to the rust fungus
Phragmidium Rubi-Idaei. More common on
wild than on cultivated plants. Cut out old
canes as soon as they have fruited, and keep
stools free of dead leaves and rubbish.

RHODODENDRON.

Foliage.—Swellings the size of a pea to that
of a marble, at first yellowish-green, later rosy
with a whitish bloom. Due to HExobasidium
Rhododendri, and occurring on Rhododendron
ferrugineum, R. hirsutum, and R. Wilsoni.
Pick off and burn the galls.

ROSE.

Root.—Large globular swelling due to the
Crown-gall organism Bacterium tumefaciens.
Cut away and burn.

Stem.—Cracks in bark through which corru-
gated tissue-growths protrude, on which small
black fungus fruits develop. The spots at first

95

Symptoms

show a purplish discoloration of the bark
about a wound. Canker due to Coniothyrium
Fuckelianum. Cut out and burn affected stems.
Spray plants with Bordeaux mixture (7), and
paint over all wounds (5).

Dead areas appear around buds or on long
strong shoots due to Botrytis cinerea attack (see
Gooseberry).

Bright orange patches of spores appear on
the stem in spring—rust, see below.

Foliage.—Dusty white patches on leaves
and near tips of young growths. Foliage is
crumpled and fails to expand. White felted
patches on stems in winter. Mildew, due to
Sphaerotheca pannosa. Dust plants with flowers
of sulphur, or spray with liver of sulphur (7).
Prune away all trace of the fungus in spring (3).

Black roundish blotches on upper surface
of leaves, with branching threads radiating
from them. Leaves fall after turning yellow
prematurely. Destroy fallen foliage (2). Spray
from May onwards with Bordeaux mixture
(7). Yellow spots closely scattered over lower
surface of leaves, followed by brown and black
spots. Foliage sometimes falls early. Rust
due to Phragmidium subcorticium. Collect and
burn fallen leaves. Spray with potassium
permanganate (7).

Irregular pale brown spots extending rapidly

96

Symptoms
over leaf and bearing threads of greyish fungus
on lower surface. Leaf withers and drops, and
whole plant dies. Most frequent under glass.
Destroy all fallen foliage (2) and spray at first
onset of disease with Bordeaux mixture (7).
Rot due to Peronospora sparsa.

SALsIFY.

Foliage—White spots scattered over whole
of leaf surface, due to Cystopus Tragopogonis.
Destroy affected plants and spray remainder
with Bordeaux mixture or liver of sulphur (7).

SAXIFRAGE.

Foliage. — Chestnut - brown spots scattered
over leaf-surface, the leaf becoming yellow or
brown eventually. Attacking Sazxifraga longi-
folia and other allied species. Rust due to
Puccinia. Dip foliage in a rose-red solution of
potassium permanganate or spray with it (7).

Scrua.

Foliage—Scattered brown spots. Rust due
to Uromyces Scillarum. Remove foliage and
spray healthy plants with Bordeaux mixture.

Flower.—Smut due to Ustilago Vaillantii.
See Chionodoxa.

SEAKALE.

Root.—Black specks in section of root,
followed by rot due to a bacterial attack.

Swellings on root, similar to those produced
by Plasmodiophora Brassicae on cabbage

97 H

Symptoms

(q.v.). In both diseases destroy plants, and
plant next year on another site.
SEMPERVIVUM.

Foliage.— Covered with yellowish - brown
spots. Rust due to Endophyllum Sempervivi.
No cure known; burn.

SENECIO PULCHER.
Foliage.—Rust, see Cineraria.
SNOWDROP.

Whole plant covered with grey mould and
rotting. Due to Botrytis Galanthina. Remove
bodily and burn, taking care to distribute the
spores as little as possible.

SPINACH.

Foliage—Rounded or irregular pale yellow
spots, dotted after a while with tufts of black
fungus threads, the fruits of Heterosporium
variabile. Spray with liver of sulphur (7).

Greyish dense velvety patches covering
considerable areas on the foliage, which finally
dies and becomes rotten. Burn affected parts
so that they do not harbour the resting spores
of the fungus, Peronospora effusa. Spraying
with liver of sulphur may check the spread of
the fungus (7).

Sroox.
Seedlings.—Damping off, see Cress.
STRAWBERRY.
Foliage.—Brown or reddish circular spots,
98

“NOTLDOAAINT WUOMWIS OL FO SHAVAT
@IVOS AHSIIA AVAG GNV GamNOTMOsId PNIMOHS GhLigq Wdodrv(, AISVaAsId AO NOILIIR ASUPASNVUT,

Wika

; A
; NC ata"

THE DAFFODIL FLY IN VARIOUS STAGES.

Symptoms
later with a dead-white centre, bearing numerous
spores which germinate at once, and later in
autumn others which mature only in spring,
due to Sphaerella Fragariae. In autumn cut
off all foliage, allow to dry somewhat, then burn
(assist if necessary with a little paraffin).

Leaves curl and become covered with
powdery white growth, often spreading to the
fruit. Mildew due to Sphaerotheca Humuli.
Spray with liver of sulphur or dust with
flowers of sulphur at the first onset of the
attack. Most prevalent in draughty places.

Fruit—Otten attacked by Botrytis cinerea
when in damp, ill-ventilated spots, causing
fruit to rot, and to bear a felt of greyish fungus

fruits.
Swzet Pua.
Same diseases and treatment as Culinary
Pea (q.v.).
Tomato.

Root.—Killed by Phytophthora cryptogaea.
Plant wilts. Treatment, see Calceolaria.

Stem.—Brown stripes on stem. Stripe dis-
ease due to Bacillus sp.? Cut out diseased
stems and burn.

Foliage—Yellow spots, felted beneath, due
to Cladosporium fulvum. Ventilate freely,
Spray with Bordeaux mixture (7).

Black spots. Blight. See Potato.

99

Symptoms
TuLr.

Foliage and Flower Stem.—Yellow or brownish
spots scattered over the foliage, which may be
malformed and crumpled in consequence.
Flowers also spotted and, if weather be damp,
quickly rotting, and covered with grey mould.
Black resting bodies among scale leaves at
neck of bulb or in soil. “‘ Fire” or tulip disease
due to Botrytis parasitica. Remove badly
diseased plants and destroy. Collect and burn
diseased foliage. Do not plant in infected
beds, and protect from cold winds and spring
frosts.

Turnie. Club-root. See Cabbage.
VERBASCUM.

Foliage —White powdery growth on surface
of leaves. Mildew due to Oidiwm sp. Dust
with flowers of sulphur.

Vinca.

Foliage.—Dark chestnut heaped-up spots on
surface of leaves, which are usually narrowed
and yellower than normal. Rust due to
Puccinia Vincae. Dig up and destroy affected
plants, as fungus is perennial in the tissues.

VINE.

Foliage —Puckered and covered with whitish
powder, subsequently spotted. Fruit whitish,
afterwards marked with darker spots. Mildew,
due to Otdium Tuckeri. Apply flowers of sul-

100

Symptoms
phur (7). Attend to ventilation and avoid
draughts.

Fruit—Brown spots later bearing grey mould.
Botrytis cinerea. Keep air in slight motion so as
to avoid drops of water on the berries. Remove
any cracked fruits.

Brown spot with a definite outline, covered
with tiny raised fruits. Anthracnose due to
Gloeosporium rufomaculans. Burn affected
berries and spray rods with Bordeaux mixture
just before vine starts in spring.

VIOLA.

Stem and Leaves.—Yellow spots bearing at
first cup-shaped receptacles full of fungus
spores, later brown spores of rust fungus
Puccinia Violae. Destroy diseased plants.
Spray remainder with potassium perman-
ganate (7).

WALLFLOWER.

Root.—Club-root. See Cabbage.

Foliage and Stem.—Upper part of shoot and
frequently whole seedling covered with greyish-
white mould, the fruiting threads of Perono-
spora parasitica. Destroy affected plants and
spray seedlings with Bordeaux mixture (7).
White rust (see Cabbage) sometimes attacks
wallflowers.

101

CHAPTER VI
ANIMAL PESTS OF THE GARDEN

THE animal pests of plants, unlike the fungi, which
for the most part restrict themselves to one or a few
hosts, are frequently somewhat general in their
attacks. This statement must not be taken to
apply too widely or it may be misleading. For
example, certain scale insects and aphides, and even
caterpillars and their kin, have a very limited range
of food-plants, but it is true to the extent that
some groups of pests are better dealt with all together
than by repeating their names, etc., time after
time under their host plants. Again, several
divisions of the animal kingdom include pests of
cultivated plants, whereas, besides fungi, few pests
occur in other branches of the vegetable kingdom.
It is not surprising to find this is so, since all animals
depend directly or indirectly upon plants for food.
Of the larger animals—the animals that in
colloquial language are “animals” —with warm
blood and a covering of hair, the weasel, stoat,
102

Mice, Rabbits

shrews, bats, and one or two others which are
carnivorous, are to be regarded as friends of the
garden, while mice, rats, rabbits and hares, and
sometimes the squirrel, are distinctly harmful. Of
all the ‘‘ mice,” perhaps the short-tailed field mouse
is the worst, but other mice and voles commit serious
depredations at times, especially among bulbs and
seeds, either fresh-sown or left to ripen. The
efforts made to destroy owls and kestrels often lead
to an inordinate increase in these troublesome
creatures, which will often gnaw the bark of trees in
hard weather and expose the wood below to drying
up. Trapping (the brick trap or figure-of-four trap
or a break-back trap are best) is the only means open
to the gardener, though sometimes the strewing of
chopped-up furze about choice plants will protect
them, and of all baits probably a small piece of fat
bacon or a piece of tallow are the most effective.
Where rabbits or hares are troublesome, trapping
again must be resorted to, but the protection of the
garden by a wire fence with at least nine inches below
ground, put up before anything is planted, and the
whole ground thoroughly scoured to destroy rabbits
and hares, is the wisest course. For some reason
the choicest apples in a plantation are nearly always
the ones to suffer attack upon their bark by these
gnawing animals, Cox’s Orange Pippin, for instance,
coming in for marked attention, while others around
are neglected. If trees are barked in this way it is

103

Moles, Birds

well to cover the wounded part with a plaster of
clay and cow dung to prevent the drying out of the
wood and to encourage the bark to grow and cover
the wound as quickly as possible.

The mole is an insect feeder, and if it were not for
its habit of tunnelling and of making unsightly
mounds would be regarded as a friend, but when it
burrows along under a row of newly germinated
beans and throws its unsightly casts up on what
should be a smooth lawn, this too cannot but be
regarded as a pest in the garden and must be trapped
accordingly.

We have said nothing of the use of poison placed
where the animals are likely to pick it up, for animals
so killed may be eaten by others which would like-
wise suffer, but the use of virus for killing rats is not
open to this objection, and is a valuable aid for
ridding a garden of these pests for a time, but the
treatment needs repetition at intervals.

Comparatively few birds do any great damage in
the garden, and even some of the most troublesome
do some good at times. Exception must perhaps
be made of the jay [whose depredations among peas
(aided by the hawfinch) are scarcely counterbalanced
by the beauty of its plumage] and of the cheerful
piping bullfinch, We may check his liking for
buds, and hinder the tits from damaging them too,
by a timely application of a lime-sulphur or lime-
spray, and bushes may be protected by lacing black

104

Seed Protection

thread here and there about them or by protecting
them within a fine-meshed wire cage. Black thread
stretched two or three inches above the rows of
peas and other seeds forms as efficient a protection
against birds as the wire cages made for the purpose,
and sparrows may be hindered by the same means
from destroying crocuses in town gardens. Netting
must also be resorted to to protect fruit from black-
birds and thrushes where they are protected, and
from starlings, birds far too valuable to destroy.
Seeds such as peas and beans are best protected from
mice and birds by damping them with water and
then sprinkling red lead over them. Linnets and
chaffinches are often troublesome where seed is
being saved, and may also need to be excluded by
means of nets or pieces of curtain tied over the
seeding plants. Rooks rarely come actually into
the garden, but walnuts may suffer from their power-
ful beaks, and possibly jackdaws also may help to
destroy them. Waterfowl and water plants rarely
both succeed in the same habitat, and sparrows
especially are a nuisance in town gardens, where
they use the leaves of water lilies (which suffer
severely from their sharp claws) as platforms from
which to drink.

Fish are extremely useful in the ornamental
water. Not only do they keep down the plant-eating
insects, but many, like the roach and carp, feed upon
the troublesome flannel weed.

105

CHAPTER VII
THE NATURE OF INSECT ATTACKS

THE greater part of the damage done to garden
plants is the work of insects, and few plants are
immune from their attacks.

The number of different species of insects is
immense, and the diversity of their food is only
exceeded by the diversity of their forms. Different
as they are in size and appearance, however, they
have certain characteristics in common, viz. the
body and its appendages jointed ; the body separable
into three distinct parts, head, thorax, and abdomen;
six legs (and in addition in caterpillars, etc., some
sucker feet) ; in the mature state two or four wings
(rarely none) ; breathe through holes in the sides of
the body, not through the mouth; have “ feelers”
or antennae attached to the head (these are organs
of touch and hearing, and probably also of scent) ;
and usually progress from egg to perfect insect
through a remarkable series of changes easily seen
in the history of the moth, where the egg hatches

106

AMERICAN BLIGHT IN VARIOUS STAGES. —|— SIGNIFIES NaTuRAL SIzE.
1. The Fly. 2. The Insect. 38. Showing its effect upon a fruit-tree shoot.

DADDY-LONG-LEGS OR CRANE FLy.
1, Male Daddy-long-legs. 2. Female Daddy-long-legs. 3. Eggs. 4. Grub. 5. Chrysalis.

qq aio NY

“SDNTS ONLI VIL WOOF Aol

Insect Characteristics

out into a caterpillar which feeds by biting leaves,
moults half-a-dozen times or so, finally becoming a
chrysalis without legs or wings, almost quiescent,
and doing no feeding, which in its turn becomes a
moth which crawls out of the chrysalis case, dries
its wings, feeds by sucking the nectar of flowers
through a long tubular mouth, and which lays eggs
(if a female) before it dies, usually on or near the
caterpillar’s food plant. This progression is less
readily seen in such insects as greenflies, where,
although it exists, the changes are less profound
and the insect is active in all its stages.

Reference has just been made to the different
modes of feeding seen in the adult moth as con-
trasted with the caterpillar. The former obtains
its food by sucking, the latter by biting. This
distinction is very important, and serves to divide
two great groups of insects from one another so far
as their work in the garden goes, viz. those which
bite, and those which pierce the tissues of plants
and suck the sap. The latter thus obtain their food
from the interior of the plant, and i is impossible to
poison their food without at the same time killing the
plant ; the former eat both inner and outer parts of
the plant, and it is possible to cover the food with a
poison which will not find its way into the plant,
but which will be swallowed, and will kill any insect
that bites the plant. This method of attack cannot
of course be followed in dealing with those insects

107

Mode of Feeding

that burrow into the tissues like the grubs of the
chrysanthemum leaf-miner, or the caterpillars of the
goat-moth or leopard-moth which feed on the wood
of trees. Nor is it possible to reach the insects that
feed underground by means of poisons applied to
their food. Nevertheless, this distinction between
insects made by their manner of feeding is of
enormous importance, and the latter is one of the
first things to ascertain regarding any pest with
which we may have to deal. The following Table
shows the principal biting and piercing and sucking
insects affecting plants.

Insects Feeding by Biting or
Gnawing

Caterpillars of all butterflies and
moths.

Larvae (usually caterpillar-like)
of all sawflies.

Grubs of beetles and the mature
beetles themselves.

Grubs of two-winged flies like
the onion, carrot, and celery
flies, and the daddy-longlegs.

Wasps and ants.

Thrips.

Earwigs, cockroaches, crickets.

Insects Feeding by Piercing
and Sucking

Greenflies and other aphides in
all stages.

Scale insects in all stages. «

Plant bugs, including the cuckoo-
spit insect in all stages.

Two-winged flies generally in
mature stage.

The second most generally significant thing in

the life of the insect is the fact that it breathes
through several holes (called spiracles) ranged along
the sides of the body, and communicating with tubes
which convey the air throughout the body. It is

108

Life~histories

therefore possible to suffocate insects by covering
these holes, a matter to which we shall again refer.
These holes may be easily seen in many caterpillars,
as their positions are frequently marked by different
coloured spots on the sides of the joints.

The third important thing to know is the life-
history : to discover at what stage the insect is
capable of doing damage, and at what period in its
life it is most open to the application of methods of
repression. For example, it is easier to cut out the
ege-bracelets of the lackey-moth during pruning in
winter than to destroy all the caterpillars by spray-
ing in spring ; it is easier to kill all the caterpillars
by waiting until they have entered their tents at
dusk and then cutting them out than to wait until
they are larger grown and attempt to deal with
them by hand-picking ; it is easier to deal with the
grown caterpillar than to collect the chrysalides, or
to capture the moths. To gain the knowledge neces-
sary for effective dealing with individual pests
entails the most careful and detailed examination
into the habits and life-stories of the pests, and this
is still in progress in connection with many of them.
Such detailed accounts would take far more space
than is available in the present little book, but it is
hoped that the plan adopted will prove useful in
indicating not only general methods, but special
methods in particular cases.

109

CHAPTER VIII

THE GENERAL SYMPTOMS OF INSECT
AND MITE ATTACK

THE presence of insects is generally easy to detect,
and where the damage done is suspected to be of
insect origin search should be made diligently to
discover their presence.

The common symptoms of insect attacks are :

I. Symeroms PRODUCED BY Bitrina INSEcTS

1. Clean-cut holes in the tissues: caterpillars,
larvae of sawflies, grubs, beetles, cockroaches,
crickets.

[N.B.—Other causes for such holes are:

(a) Attacks of slugs or snails, when usually there
will be slimy tracks on or near the damaged
areas, and of woodlice.

(b) The results of attack of shot-hole fungi, when
the hole is usually surrounded by a brown
corky line.

110

COMMON CoCKCHAFER,

1, Cockchafer. 2. Grub. 3. Chrysalis.

Biack CURRANT GALL MITE.

1. Black Currant Gall Mite (magnified 400 times). 2. Twig of Black Currant
with healthy buds. 38. Twig of Black Currant with infested buds.

THRIPS.

land 2. Immature Thrips. 3 and 4. Mature Thrips.
8 and 9. Other Species of Thrips.

SNAKE MILLEPEDES.

1. Julus londinensis, i) 2and 3, Blanjulus yuttulatus (nat. size
and mag.). 4. Ju/us terrestris. 5. Teller. 6 and 7. Poly-
desmus complanatus (nat, size and mag.)

Insect Injury

(c) The result of damage to the bud by the beak

of a bird or similar injury.]

2. Scalloped edges to leaves: weevils, especially
pea and bean weevils,

3. Borings in stems: caterpillars of goat-moth,
wood leopard, clearwing moth in apple or currant ;
shot-hole borer beetle, bark beetles, etc. ; pith moth
(apple, etc.) ; raspberry moth.

4. Blisters in foliage: caterpillars of blister-
moths on apple, blackberry, etc.; celery fly,
parsnip fly, chrysanthemum or marguerite fly,
etc.

5. Destruction of buds: carnation fly; swede and
cabbage midge, causing “ blindness ”’ in all kinds of
cabbage, cauliflower, and swede plants ; bud moth
(apple, etc.)._

6. Destruction of roots: cabbage-root maggot,
wireworm, leather-jacket, chafers, including cock-
chafer, rose chafer, garden chafer, pea and bean
weevil grubs ; caterpillars of ghost moth.

7. Destruction of lower part of stem so that plant
topples over: pests mentioned under No. 6, with
addition of onion maggot and surface grubs (cater-
pillars of various brown night-flying moths, which
hide in soil by day).

8. Tunnelling in roots: wireworm, grub of
carrot fly.

9. Tunnelling in fruit: caterpillar of codling
moth (apple), larvae of sawfly (apples, etc.), currant

111

Insect Injury

moth, grape moth; raspberry beetle grub (rasp-
berry, blackberry, loganberry).

10. Holing fruit: caterpillar of winter and other
moths (apple, pear, etc.); tomato moth; garden
chafers ; wireworm, ground beetles (strawberries)
[N.B.—tThe last are also attacked by slugs, mille-
pedes, and birds], wasps, ants, earwigs.

11. Parts of flowers devoured: garden chafers,
rose chafer, raspberry beetles (raspberries, etc., and
strawberries), mustard beetle, apple blossom weevil ;
earwigs.

12. Bark gnawed or buds eaten out: raspberry
or vine weevil.

13. Upper or lower surface of leaf destroyed, and
leaf skeletonised or only one surface left: sawfly
larvae, e.g. pear and cherry, rose, spiraea.

14. Leaf rolled on itself, or two or more leaves
fastened together by silky threads: various cater-
pillars, especially of minute moths; larvae of saw-
flies, e.g. rose ; leaf curling midge of pear.

[N.B.—The rolling ig sometimes done by larvae,

sometimes it occurs as the result of egg-
laying ; the object in either case is to pro-
vide a shelter for the larvae and chrysalides. |

15. Tents of numerous silky threads: cater-
pillars of lackey (various colours, in stripes), lesser
ermine moth (cream with black spots) ; etc.

16. Borings into seed (especially peas and beans)
by beetles.

112

Insect Injury

II. Symproms PRODUCED By SucKkrina INSECTS

17. Minute holes accompanied by puckering of
the leaves, but without insects present at the time :
bugs have punctured the young leaves and stem in
the bud.

18. Curling and often discoloration of the leaf,
accompanied by the presence of greenfly (aphides),
or their cast skins—caused by the greenflies of apple
and plum (some species), cherry, etc.

19. Spittle-like spots on foliage of various kinds,
and on young shoots : the bug known as the cuckoo-
spit.

20. Drops of a sticky consistence among flower-
buds and young leaves of apple (Apple Psylla) and
pear (Pear Psylla).

21. Honeydew on leaves: greenflies or scale
insects. [Bees often visit plants for this honeydew,
and ants do the same, obtaining it straight from the
insects. Whenever ants are seen to be busy on plants
search should be made for greenflies or scale insects. ]

22. Black fungus growth on leaves: Fumago sp.
grows on honeydew, and is a sign of the presence of
greenflies or occasionally of scale insects.

23. Flowers develop in a one-sided way, e.g.
chrysanthemums, buds grow only on one side;
apples, and occasionally pears, show roughened
warts: they have been punctured by bugs during
their development.

113 I

Galls

24. Woody plants show curving of shoots, e.g. in
apples, currants, and gooseberries, usually accom-
panied by a discoloration of the bark: early aphis
attack.

25. Woody plants show stunted growth and
general unthriftiness: they should be closely
examined for scale insects on the bark.

26. Palms, ferns, and aspidistras, etc., show
discolored spots on the leaves or leaf-stalks : search
should be made near the ‘“‘crown”’ and mid-ribs for
scale insects.

III. Gaus, THAT 18s, ENLARGED GROWTHS,
PRODUCED

27. The attacks of insects and other animals of
many different types result in enlarged growths
which take on extraordinarily different forms accord-
ing to the kind of insect and the kind of plant. The
galls upon the oak illustrate this in a remarkable
_. way, and perhaps no more remarkable story is to
be found among the annals of insect life than that
of the gall insects of the oak. This is not the place
to do more than refer to the fact that oak-apples,
artichoke galls, marble galls, spangle galls, currant
galls, and many others, all of which may be found)
in practically any oak coppice, are the result of
insects of various kinds laying eggs in the oak, the
grubs which hatch from them being found in the
galls and feeding upon their tissues.

114

Galls

[NV.B.—Similar enlarged growths formed by fungi
have already been referred to, e.g. azalea
gall, club-root, wart disease of potato, leaf-
curl of peach, crown gall. In these no
insect is to be found.]

The principal galls calling for mention as needing
attention in the garden are big-bud in black currants
(due to a mite; the big-bud of hazel is similar but
distinct) ; leaf-blister galls of pear leaves ; rose galls
(Robin’s pincushion, and the round swellings on
rose leaves) ; weevil galls on cabbages and turnips
(usually near “collar” of plant, but not under-
ground like club-root, a much more serious pest) ;
woolly aphis galls on apple, etc.; aphis galls on
poplar leaf-stalks ; Phylloxera galls on vine roots.

IV. Orner Symproms

28. Tiny flecks of whitish colour over the whole
or a great part of the surface of leaves and flowers :
thrips (often called thunder bugs).

29. Similar discoloration or brown or reddish or
even fiery red markings, with a fine web on lower
surface : red spider (a mite—not an insect).

30. The presence of excrement or the remains of
partially devoured tissues; e.g. bulb mites leave a
dust-like mass in the bulbs they destroy. The mites
themselves are like grains of sand in this debris.

115

CHAPTER IX

METHODS OF DEALING WITH INSECT ATTACK

GENERAL

I. Thorough Cultivation.— Deep digging and con-
stant hoeing not only in themselves tend to the
healthy growth and development of the plant, but
result in exposing many noxious insects to the
observation of birds, and in disturbing them so
that their depredations are lessened, and in some
cases, as with the wireworm in the pupal stage, they
are actually destroyed. Closely connected with this
is—

II. Timely Application of Manures, such as
nitrate of soda, to bring the plants through a period
of attack and enable them to overcome to some
extent its effects. Special applications of I. and II.
are found in connection with the grubs of chafers
which feed on roots of almost all sorts, wireworms,
leather-jackets, and Bibio (or St. Mark’s flies), and
caterpillars of the garden swift moth. And of II. in
attacks of the turnip flea beetle and pea and bean

116

Cleanliness

weevil, both of which feed on young plants, in the
first case of all kinds of plants belonging to the
cabbage family, including wallflowers and stocks,
and also on mignonette, etc., and in the second
especially on the two plants mentioned.

III. Cleanliness—The prompt removal of all
refuse and its proper disposal either by composting,
burial, or burning are great aids. This applies to
all parts of the garden, and to trees as well as to
herbaceous plants. Woody parts should be burned,
soft parts, unless diseased, composted or used as
green manure.

Hedge bottoms and banks, rough grass, and so on,
should also be attended to, for in such places as these
many pests hibernate; e.g. turnip flea beetles, weevils,
and the like, as well as woodlice, slugs, and other
pests not insects. Stones, bricks, and such plants
as thrift used as edgings to beds are frequently
harbours for pests and as such need particular
attention, and under stones the jelly-like eggs of
slugs and snails are frequently to be found.

Crevices in walls of greenhouses and upon which
trees are trained often serve as hiding-places for
various pests. They should be reduced to a mini-
mum by pointing, and where necessary painted or
whitewashed at intervals.

All loose bark should be removed from vines
during the winter. .

Walls and fences around gardens often form

117

Egg Destruction

winter shelters for the angular slate-coloured pupae
of the cabbage butterflies. They should be searched
out and destroyed.

A special method of cleansing should be adopted
with fruit trees and bushes, and with ornamental
trees which are not too large to deal with. Moss,
lichen, and loose bark all afford lurking places for
insect pests, and may be removed by spraying with
caustic soda (1 lb. to 10 gallons of water) between
November 30 and February 15. This must be done
only in the dormant season, and only on trees and
shrubs that drop their leaves completely in autumn.

IV. Destruction of Eggs.—There is a widespread
belief, sometimes fostered by advertisement, that
caustic winter washing destroys insect eggs. This
belief is erroneous. No wash that can be safely
applied will destroy insect eggs. When the eggs are
about to hatch a proportion of the young may be
destroyed, and hence late use of this spray (mid-
February) is likely to be productive of more good
than early, but that is all. The spraying also
loosens many scales under which eggs of scale in-
sects were lying, and these are liable to be destroyed.

Hand-picking of eggs where they are laid in
masses can be adopted with advantage.

The eggs of the lackey moth are laid as bracelets
round twigs of fruit and rose trees, and may be
pruned out during winter; the cocoons of the
vapourer moth and of the gold tail, and the egg

118

Egs Destruction

masses of the March moth, and a few others, and
also at times of the lesser ermine (but these are as
it were glued over and more difficult to see) may
be similarly dealt with. The large cabbage white
butterfly also lays its yellow eggs in groups, and the
destruction of these will go far to keep this pest in
check.

The gooseberry and currant sawfly lays its eggs
in April in slits along the leaf-veins of its food plants,
and again in June. Search for these will avert the
disaster a severe attack of this pest brings in its
train. See also under III. for eggs of slugs and
snails.

While winter pruning is in progress close observa-
tion should be kept upon the trees to discover eggs
and hibernating stages of pests. The younger
shoots may be covered with the shining black
oblong eggs of one or other of the species of aphis,
or the apple spurs and young twigs will bear the
drab elliptical eggs of Apple Psylla, or the green (later
orange) eggs of the winter moth tucked singly into
crevices, as well as those of the insects enumerated
above. Various small caterpillars may also be dis-
covered and plans laid for their destruction as soon
as circumstances permit of measures being taken.

V. Prevention of Hgg-laying—In certain cases
measures may be taken to prevent egg-laying (see
also trapping). The use of substances obnoxious to
insects may drive them to other gardens or districts.

119

Prevention of Egg-laying

The most frequently used of these substances is
paraffin. It is used in three ways. (1) As an
emulsion for spraying chrysanthemums, marguerites,
and celery against the marguerite and celery flies
respectively. The emulsion must be used at
summer strength and applied from March onwards
to the former and May onwards to the latter plants.
(2) For damping sand or sawdust to sprinkle along
the rows of seedling cabbages, cauliflowers, and
similar plants, and onions, to deter the respective
flies [cabbage root fly (see below) and onion fly]
from visiting the plants, beginning in May or
earlier in very early districts, and repeating at
ten-day intervals. (3) For the same purpose
where the onion fly is concerned, strings carrying at
intervals pieces of rag may be stretched above the
onion bed and the rags damped by dipping in a jar
of paraffin once every fortnight from early May
onwards. The same measure might be tried with
the carnation fly, and possibly the narcissus fly.
Naphthalene (often called “ carbon ’’) is used to
sprinkle on clothes to prevent the clothes moth
from laying its eggs, and camphor has the same
effect. Crude naphthalene is the basis of several
proprietary articles that are used to drive insects
from plants and are known as soil-fumigants and
recommended as means of guarding plants from the
attacks of wireworms, etc. When camphor again
becomes lower in price camphor water sprayed or
120

Prevention of Egg-laying

sprinkled over cabbages when the white butterflies
are on the wing will check egg-laying by them.
Meanwhile pyridene compounds might be used on
any but those soon to be eaten.

When cabbages or cauliflowers have been planted
tarred felt or cardboard discs may be placed round
the stem and pressed close to the ground. These
do not prevent egg-laying, but do prevent the fly
from laying its eggs near to the cabbage stem, and
so ensure that the grub dies before it reaches its
food plant.

VI. Prevention or Postponement of Egg-hatching.
—A coating over eggs may postpone if it does not
altogether prevent their hatching until the food
plant has grown so much that,the harm the insects
will do is greatly diminished. Aphis and Psylla
eggs on fruit trees may be so treated by means of
lime washing or spraying with lime-sulphur.

Spraying with caustic wash or strong paraffin
emulsion is an aid to preventing the hatching of
the eggs of scale insects, since the shelter the scale
provides is often removed by this winter spraying.

VII. Poisoning or Suffocation of Insects in the
Active Stage by Spraying.—The chief ends of spraying
against insect attack lie in the direction of poisoning
biting insects by the food they eat, or all insects
through their skins, or by suffocating them by
covering their breathing pores.

Where biting insects are alone concerned the

121

Poisoning Insects

best sprayis lead arsenate(1 lb. to 20 gallons of water).
This may be used for all biting insects, including
caterpillars, larvae of sawflies, and beetles, so long
as the parts to be sprayed are not to be eaten.
It is safe to use on trees bearing young fruit, and on
young cabbages and turnips that have not developed
the edible parts, but not on old ones, or on fruits
that are well developed. It is of course useless to
spray against insects that feed upon parts of plants
which the spray cannot reach. It is the best spray
to use against all caterpillars that feed upon fruit
trees and roses in early spring, including the winter
and allied moths, cigar-case bearers, etc., and all the
leaf-eating and bark-gnawing weevils and the
raspberry and loganberry beetle; and is useful
against the turnip-flea beetle feeding on the seedling
cabbages, ete.

Where gooseberries are to be picked green lead
arsenate is not safe to use, but hellebore powder
may be dusted on the bushes attacked by goose-
berry sawflies, or mixed with water and sprayed on.

It should be clearly understood that this spraying
should be done at the season at which the pest
aimed at begins its feeding ; that the insects them-
selves need not be covered with the poison but
their food must ; that trees or plants in bloom should
not be sprayed with lead arsenate, since bees may be
killed.

Where codling moth attacks apples, spraying

122

Spraying

should be done with the lead arsenate within three
weeks of the fall of the petals so as to catch the
caterpillar before it enters the fruit.

For sucking insects sprays containing nicotine are
the most effective. They kill through the skin, and
young caterpillars and even the raspberry beetle may
also be killed by it. Where both aphis or Psylla
and caterpillars are attacking fruit trees in spring
this is therefore the best spray to use, and it is most
effective if applied just before flowering in the case
of apples, just after with pears, cherries, and plums.
The attacks of Capsid bugs upon apples are only to
be dealt with effectively by means of a nicotine
wash applied when the active green bugs are piercing
the young fruits in May, the results of their work
being conspicuous in autumn in the shape of rough
warts on the surface. The same should be used
where bugs are attacking flower buds, etc.

Paraffin emulsion and quassia and soft soap are
also useful sprays against aphides, and recently a
very efficient spray containing saponin instead of
soft soap has been devised. All of these kill by
suffocating the insects hit. They do not poison the
food, and it is useless to use them unless the insects
are present and in a position to be wetted thoroughly
with the spray.

VIII. Suffocation by Dipping.—Where plants in
pots attacked by aphis or scale have to be dealt with,
and especially where they are attacked by mites, asin

123

Hand-picking
the case of Cyclamen, Begonia, Gloxinia, and the
like, dipping is an excellent treatment. The foliage
alone is dipped in a solution made by dissolving
in 1} gallon of warm water a handful of soft soap into
which flowers of sulphur have been well kneaded.

IX. Hand-picking.— Where cabbages approaching
maturity are attacked by caterpillars, or where the
attacks of the gooseberry sawfly or the magpie moth
caterpillars on gooseberries and currants have been
neglected until the fruit is nearly ready for use, hand-
picking is the only safe method to adopt. Surface
grubs (caterpillars that hide under ground and
feed on plants at night) are often best dealt with in
this way too. Early in the season, just after the
caterpillars of the cabbage white butterfly and the
gooseberry sawfly hatch out, they feed in companies
and may be collected and destroyed with little
trouble. Several fruit-tree-feeding caterpillars form
webs to which they retire at night or in damp
weather, and these may readily be cut out from the
trees when the caterpillars are at home and the whole
colony destroyed. Leaf-rolling caterpillars may also
be dealt with best by hand-picking. Slugs and
snails are best dealt with by visiting their haunts
at night armed with a powerful light and a pair of
scissors, or a hat-pin, and a pail containing some salt
water or paraffin.

Brushes may be obtained wherewith to remove
the hordes of greenflies that locate themselves upon

124

Hand-picking
tender shoots, although spraying is generally prefer-
able.

A modified form of hand-picking is used with
mealy-bugs, which are touched by a brush wet with
methylated spirit, and woolly aphis upon apple tree
are treated in the same way.

None of these methods are capable of use on a
large scale, nor is the commonly employed method of
pinching between finger and thumb the blisters made
by the grubs of the celery fly, and the marguerite or
chrysanthemum fly, effective as it is on a small
scale. Where only a few plants have to be dealt
with these methods are not to be despised. Hand-
picking too is the only method to adopt when roots
of plants in pots are attacked by wireworms or
weevil grubs (Otiorrhynchus).

A combination of the dipping method and hand-
picking has often to be adopted where scale-insects
attack plants. The scales often cling so closely to
the stalks and leaves of palms, orchids, and so on,
that their removal with a blunt stick and the spong-
ing of the foliage with the soft-soap-sulphur dip
referred to on p. 134 is desirable.

The collection of the grey angular chrysalides of
the white cabbage butterfly from their winter quarters
under the rails of fences, window ledges, and so on,
would be a material help in checking the ravages of
this pest upon our vegetables.

Wormy apples too should be collected before the

125

Collecting Pests

sawfly or the codling moth caterpillar, as the case
may be, leave them for their winter quarters. Pigs
make excellent collectors. Pears are often caused
to drop prematurely by the pear midge, the grubs of
which, hatched from eggs laid in the flower, live and
feed in the young pear to the number of about forty.
By mid-May the pear attacked has greatly increased
in size and often begins to turn black. All such
should be collected and destroyed before the grubs
fall out to the earth to hibernate.

Both apples and currants are attacked at times
by the caterpillars of clearwing moths that
bore into the shoots and cause them to wither.
These shoots should be removed as soon as the
damage is apparent and burned with the culprit
inside.

X. Shaking.—A few beetles are better collected
by shaking the attacked plants over a sheet spread
beneath than by any other method. The weevils
(Ottorrhynchus sp.) that attack fern-fronds, and leaves
and shoots of vines at night and other plants growing
under glass, are best dealt with so, and nothing is so
effective when these same weevils feed upon raspberry
canes. When the dead unopened blossoms in the
trusses of the apple betray the presence of the apple
blossom weevil this method too should be used, but
in this case it will be effective in the daytime, while
in the other cases after dark is the best time, since the
weevils concerned generally hide in the daytime,

126

“UAWSAT IPMS [Be
ad Ayperaads quq

ATUL STAIR pad
‘asa wood

IWJ{NAIIZ-AOY WOT, Paurryqo aq
Spasn ary AVI asvedh- pany

AdV:

au d

NV!

7
t

if

asvauy

“APL sayour g quoqe
doded yooud-asvais Suorys JO opLur aq pyWoYys spuxq asatlL,

‘NOILVUYIIUG fO ASUAOO NI GNVA-ASVAUD) V

OVAL OLE} TOY

PUY poos w stelop SELL

NV WO AsSve ELL Wa OW
oH ANVEHRAV]] AUVNTERTO NY AL SV NOOS SV SUVITI

‘AML ol
WoW ,SL Laoay «

Trapping

often in the soil, where their eggs are laid and where
their larvae feed.

XI. The chrysalides of many sawflies, such as
those attacking the apple, pear, cherry, gooseberry,
rose, and Solomon’s seal, are formed about two inches
beneath the surface of the soil and remain there
throughout the winter. They may be destroyed by
skimming off the top two inches or so and burning
it during winter or burying it deeply. Sawflies
rarely travel far, and this prevents the persistent
return of the attack which so frequently occurs.

XII. Trapping —The females of the winter moth,
mottled umber and March moth, are practically
wingless, and they have therefore to walk up apple,
pear, and plum trees in order to deposit their eggs
near the tips of the shoots. The tying of a band of
paper about 5 inches deep around the stem of the
tree at a height of.about 3 feet from the ground, and
keeping upon it a ring of sticky grease from the
beginning of October to the end of March, will effect
the capture of the majority of these moths, which
will die on the “ fly-paper”’ so made. Haybands
similarly tied in late August round the trunks of
trees attacked by codling moth will afford shelter
for the caterpillars, which leave fallen fruits and seek
a crevice in the bark to hibernate. But lead
arsenate spraying in May is better (see p. 132).

Where slugs are prevalent cabbage or lettuce
leaves laid on the soil surface near their haunts will

127

Trapping

lead to the capture of many. They should be
examined daily.

Millepedes and soil insects like wireworms are
best trapped. Pieces of potato or carrot are buried
about an inch below the soil, the place being marked
with a stick. The traps are examined daily and the
captives killed. Potatoes halved and hollowed out,
placed with the hollow side down on soil near the
haunts of woodlice, will capture these troublesome
pests. The traps need daily attention, and as with
all these pests, hot water or water with paraffin
floating upon it will prove the best thing to kill the
captives with.

Earwigs often eat the petals of flowers. They
shelter during the day, and inverted flower-pots
stuffed with hay and elevated on stakes or lengths of
old bean stems laid near the infested plants will
act as excellent traps for them.

One or two ground beetles (as well as millepedes
and thrushes) eat holes in strawberries as they
ripen. ‘They are best destroyed by trapping in
basins or smooth tins sunk up to the rim in the
surrounding earth and baited with a piece of “‘lights.”’
These captures will be made mostly at night.

Many moths are attracted by a light, and this
is sometimes made use of to capture pests. The
results are not, however, altogether satisfactory.
Poison baits too may sometimes be employed where
it is certain that domestic animals, including bees,

128

Boring Insects

will not be likely to be injured. For surface grubs,
cockroaches, and the Otiorrhynchus weevils heaps of
clover dipped in lead arsenate may be placed on the
soil near the plants attacked. For two-winged flies
like the onion fly and for ants, syrup to which arsenic
has been added will prove attractive and deadly.

Trees in a weakly condition often form attractive
traps for bark beetles (Scolytus) and boring insects
such as the shot-hole borer (Xyleborus). If they are
cut down when the pests are at work and promptly
burned the pests will be destroyed.

Bread treated with phosphorus paste is useful not
only against mice and rats but against cockroaches,
two or three species of which often do a great deal of
damage to plants growing under glass. Even more
effective is an ingenious trap where bran is the bait
and an enclosed water reservoir the death-trap.

XIII. Direct Action—Where large boring cater-
pillars like the goat moth in willow, ash, elm, or
chestnut, and the wood-leopard in apples, pears, and
other trees are at work, the most effective method of
treatment is to thrust a sharp-pointed piece of wire
into the burrows where fresh sawdust is to be seen.
If it comes out wet its work is done.

XIV. Fumigation.—Where insects are feeding in
enclosed spaces, or where they can be enclosed, the
most effective treatment is to fumigate. The effect
of smoke from a tobacco-pipe upon greenflies is well
known to all, and nicotine preparations are put upon

129 K

Fumigation

the market by various firms for fumigation purposes
at the present day. Greenflies, white flies, and scale
insects in greenhouses are best dealt with by this
means.

Fumigation with hydrocyanic acid is even more
effective, but its use in careless hands or in green-
houses attached to dwelling-houses is fraught with
danger to human life. All cracks should be closed
for any form of fumigation, and the air of the house
and the foliage of the plants should be dry. The
process should be carried out after dark, and the
house should be ventilated well before it is entered.
This is absolutely essential where hydrocyanic-acid
gas is used, for the fumes in even small quantities
are deadly to human life. The materials wanted for
the process are potassium cyanide, sulphuric acid,
water and a saucer. The sulphuric acid is diluted
and placed in the saucer. The potassium cyanide is
dropped into the acid after the door of the house has
been securely fastened, and the ventilators are
opened for at least two hours before any one is
permitted to enter the house. -The quantities
required are, for every 1000 cubic feet in a green-
house, 1 oz. potassium cyanide, 1} oz. sulphuric acid,
and 3 oz. water.

Soil fumigation has recently received more
attention than hitherto, and many soil fumigants
are on the market. Their frequent effect is to drive
soil insects to seek ‘‘ fresh woods and pastures new.”

130

Soil Fumigation

Carbon bisulphide is one of the most effective soil
fumigants. Holes are bored to the depth of about
6 or 8 inches, one to each square yard, and into each
a teaspoonful of carbon bisulphide is poured, the
hole being covered up immediately. The liquid is
very inflammable and explosive, exceedingly evil-
smelling, and rather expensive, but its fumes, while
practically innocuous to the roots of plants, are
deadly to all animals. Even mice and wasps may be
killed by their means, as well as wireworms, leather-
jackets, and the ground forms of aphides, such as
the woolly aphis and the aphis of the lettuce and of
Primula roots, Phylloxera on vines (but drowning
is often effective for that ; the roots are submerged
for three weeks), and so on.

131

CHAPTER X
INSECTICIDES, ETC.

For Biting Insects

For biting insects lead arsenate has now superseded
Paris Green, London Purple, and so on, since its use
is not likely to result in burning of foliage. It should
be purchased in the paste form, as that is far easier
to mix with water.

Lzap ARSENATE

1 Ib. paste.
20-25 gallons water.

HELLEBORE POWDER

Hellebore powder is the powdered root of Verat-
rum album. It loses its poisonous properties on
exposure to air for some time, and is therefore
valuable where edible parts of plants need to be
sprayed against biting insects. Dust on dry while
dew is on the plants, or mix with water at the rate
of 1 oz. to 1 gallon.

132

GALLS ON FLOWERS OF THE ASH.

VEG IONVAS M¥Q AAD

Insecticides
For Sucking Insects

Nicotine Soap WasH

3 oz. nicotine (95 per cent).
4 lb. soft soap.
40 gallons of water.

Dissolve the soft soap in hot water, cool, and add
the nicotine, stirring thoroughly. Dilute to 40
gallons.

PaRAFFIN EMULSION

24 pints paraffin (good lighting oil).
4 Ib. soft soap.
10 gallons water.

Dissolve the soft soap in hot water. When
dissolved pour in the paraffin with constant stirring.
Then with the aid of a bundle of birch twigs, or
better still, with a garden syringe, churn the mixture
backwards and forwards until the oil is broken up
so finely that the drops do not separate out on
standing. This will take 15 to 20 minutes. Dilute
with water to make 10 gallons.

This solution may be usedinsummer. A stronger
solution for use in winter is made in the same way,
the proportions being :

1 gallon paraffin.
14 Ib. soft soap.
10 gallons water.

133

Insecticides

Quass1a AND Sort Soap

1 Ib. quassia chips.
1 Ib. soft soap.
20 gallons of water.

Steep the quassia chips in 10 gallons of water for
twenty-four hours. Dissolve 1 Ib. soft soap in
10 gallons of water. Strain the water from the
quassia chips into the soap solution. Use im-
mediately.

Limz-SuLPHURB

This is best purchased ready-made, and used
according to the instructions given for summer

spraying.

For Mites
Sort-Soap-SuLPHUR Drie

Take a handful of soft soap and knead into it
flowers of sulphur, so that all parts are permeated
with it. Dissolve the mixture in 4 gallon of warm
water.

LiIvER oF SULPHUR

1 oz. potassium sulphide (liver of sulphur). 7

3 gallons water.
Dissolve the liver of sulphur in the water.
For spraying against red spider.
134

Insecticides

Limz-SvLPHur-Satt-Sopa
3 lb. quicklime.

3 lb. flowers of sulphur.

3 Ib. salt.

1 Ib. caustic soda.

10 gallons water.

Make the sulphur into a paste, thin and pour
over the lime; allow to boil with its own heat; stir
and add caustic soda and salt. Bring up to 10
gallons with water.

For spraying pears against the pear-leaf blister
mite; used in November while trees are dormant
only.

For Cleansing Trees ; used in Winter
Caustic WasH
1 Ib. caustic soda.
10 gallons water.

Dissolve the soda in the water.

Lime-SULPHUR

See notes above—but used at winter strength.

LIME-WASH FOR TREES

Purchase quick-, stone or builder’s lime and slake
it by adding water gradually in a tub until the lime
falls to pieces. Add more water to make a milk,
and spray on as soon as possible, covering trunk and
branches as thoroughly as possible.

135

CHAPTER XI
FRIENDS OF THE GARDENER

Tue insect pests of the garden have themselves
many enemies, and although it is probable, and in-
deed inevitable, that some of the methods advocated
for dealing with these pests will themselves result
in the destruction of friends as well as foes where
the two exist side by side, yet all possible care should
be taken to preserve these friends as far as possible.
Among them, birds occupy a high place of useful-
ness. Most birds when feeding their nestlings catch
numerous insects. Some at other times feed entirely
upon seeds and parts of plants, and it then comes
for consideration on which side the balance lies.
Is it to the benefit or to the detriment of the garden
products? We have dealt with this question in
another chapter, and pass on now to consider insect
friends. They may be divided into those that hunt
and devour insects, and those that parasitise them.
Of the former the best known are probably the
ladybirds. Ladybirds are beetles, and pass through

136

Hover Fry.
Grub 2 days old, devouring
a green fly much larger than
itself (magnified 4 times).

Hover Fiy (slightly The full-grown grub cap-
magnified). pares, Sagtecn fly on a pea
oO er and-—

lifting it clear of the leaf— extends its body in a rigid The hover fly just
attitude and sucks the juices emerged trom its chrysalis,
of its prey. the broken skin of which

is seen above.
John J. Ward, F.ELS,

MALE AND FEMALE LADYBIRDS LARVAE OF LADYBIRD BEETLE
FEASTING ON GREEN FLIES. DEVOURING GREEN FLIES (magnified).
Note the shrunken skins of their victims.

none e *

THE LACE-WING FLy. Larvae oF LAackE-WInG FLY FEEDING
ON AN APHIS (natural size),

Johu J, Ward, PFS.

Insect Friends
four well-marked stages—egg, active larva, pupa,
and perfect insect. In the second and fourth the
food of ladybirds consists of greenflies and scale
insects. Where ladybirds are abundant greenflies
rarely do very serious harm. The larvae are slate-
coloured with black spots, the pupae are found on
the foliage, and can hardly be mistaken for anything
else if larvae and ladybird are known; the yellow
eggs standing on end are conspicuous on the leaves
in spring and summer; the winter is passed in the
perfect stage.

The larvae of the lacewing fly also devour green-
flies. The curious eggs fixed to leaves by trans-
parent threads a quarter of an inch long are well
known objects which often excite curiosity. The
flies themselves with green bodies, golden eyes,
and large gauzy wings also attract attention, while
the repulsive odour they exude when touched render
them almost immune from destruction.

Hover flies are well known to all from their habit
of hovering over flowers. Most of them feed on
pollen, but their rather slug-like brown or green
larvae feed, as a rule, on greenflies.

Earwigs, ants, and wasps devour many insects,
but their good services on this side have to be
balanced against damage done to plants or fruits
on the other. The solitary wasps are, however,
wholly friendly in their habits, and their nests in
hollow sticks and the like should be preserved—

137

Ground Beetles

they are full of caterpillars or flies destined for the
food of the young. Ants rarely do direct harm to
plants, though they eat into apples, etc., damaged
by birds. They preserve greenflies, however, and
carry them, when their food supplies begin to fail,
to other plants, while their nests are a nuisance on
lawns and fields.

The numerous population of the soil contains
many friends. Insects provided with long legs and
(or) powerful. wings, large eyes, and conspicuous
jaws, are unlikely to feed mainly on plants. They
are equipped with the implements of the hunter,
and the soil abounds in such. They are mainly
beetle larvae and the perfect beetles which develop
from them. The larvae of these beetles often meet
an untimely death, because they are often straw-
coloured, have a hard skin and six legs, and are
therefore mistaken for wireworms. They are,
however, quite easily distinguished, if only by their
active movements. Their jaws are much more
conspicuous, they are of stouter, flatter build, and
generally have brown markings on the body as well
as the head. The active black or violet beetles are
often very abundant, and are familiar to all. One
or two species have been referred to as attacking
ripe strawberries, but this is the only damage
traceable to them. The devil’s coach-horse, or cock-
tail beetle, is another friend, and it and its black
larva are common in town and country.

138

Parasitic Insects

Parasites —In addition to the insects that hunt
garden pests, there are many others that feed inside
them or in their eggs. These parasites belong to
various families of insects, but the most familiar are
the ichneumons. They are easily recognised by the
abdomen being attached to the body by a thin stalk,
by the long egg-laying apparatus projecting from
the end of the body, by which they penetrate the
body of their prey, and by their long quivering
antennae. The variety of these ichneumons is very
great, for most caterpillars are subject to the attacks
of one or more species of ichneumon, and generally
each species of parasite is confined to one species of
host, while many of the parasites are themselves
subject to the attack of other parasites.

The eggs of the parasite are laid either in the egg
of the host or in the body of the larva. The grubs
that hatch from these eggs may pass their whole
life in the egg of their host, finding sufficient susten-
ance to secure full development therein ; others feed
in the body of the larvae until that is full-grown
without damaging any vital part. Some emerge
from it while still in the larval stage, others not
until it has assumed the chrysalis stage. The
masses of cocoons of one ichneumon are familiar to
every grower of cabbages. The caterpillars of the
cabbage-white butterfly are parasitised by it, and
when they are full-fed the parasites eat their way
out through the skin, spin cocoons, and become

139

Parasitic Insects

chrysalides therein, to emerge in due course and
parasitise other white butterflies. These masses of
cocoons are often destroyed in ignorance. They
should be preserved.

But for natural checks to their increase, we might
look to these parasites to do all necessary for the
control of pests. Unfortunately in the artificial
conditions of our gardens their work is not entirely
successful ; this partly because parasitised cater-
pillars become sluggish and fall easy victims to birds,
and the parasites are themselves often destroyed by
parasites.

Not only are caterpillars liable to be parasitised,
but all other pests. The brown skins, somewhat
distended, of greenflies are by no means infrequent
on the underside of the foliage they frequent. Close
examination reveals a minute hole in the skin, show-
ing where the parasite has emerged and left the
skin otherwise intact. Others still remain intact,
the parasites in them. Other insects may similarly
be attacked, while sometimes fungi are parasitic
upon pests and bacterial or fungus diseases attack
them. The caterpillar of the garden swift moth, for
instance, is often found in a ‘“‘mummy”’ condition,
with the fruit of the fungus which has invaded all
the tissues of the caterpillar and formed the mummy
projecting from its body.

Another parasite of insects frequently attracts
attention since it is found on leaves, especially in

140

Garden Friends

warm, damp weather. This is a long white worm
looking like a piece of cotton thread endowed with
rather sluggish life. It is a worm that lives in the
intestines of insects, and is absolutely harmless to
human beings.

Reference has already been made to beneficial
birds, and among other creatures, not insects, the
lizards, frogs, and toads which frequent our gardens
must be mentioned. The gardener has no better
friends. Spiders, too, are wholly beneficial, so are
centipedes,! although they often fall victims to the
gardener’s zeal for destroying pests. Worms, except
on lawns and in flower-pots, must be reckoned the
friends of the garden, and they have enemies, too, in
the garden besides the birds, slow-worms, moles,
and so on, in the curious worm-eating shell-bearing
slugs (Testacella), and in greenhouses the exotic
worm Bipaliwm kewense, frequently found among
the crocks of flower-pots.

This seems the proper place to mention the beetle-
mites (Oribatidae), which live in crevices of bark
of fruit trees, sometimes in great numbers. Because
their hard reddish bodies are frequent in canker
wounds, they are looked upon as a cause of canker,
whereas they feed upon fungus spores and lichens,
and are therefore friendly. The same may be said
of the tiny orange grubs of minute two-winged flies

1 Centipedes have only one pair of legs to every joint, the harmful
millepedes have two pairs to each joint.

141

Garden Friends

(Cecidomyidae) that are found on foliage attacked
by rust and other fungi. They feed upon the
rust spores and help to hold the fungus in
check.

It is perhaps rarely that anything can be done to
increase the number of these friends, but their lives
may at least be preserved from wanton destruction
to the general benefit of all plant-growers.

142

SPRAYING APPLE TREES AT WISLEY WITH LEAD ARSENATE,

The spraying is done before the flowers open, and again after the petals fall.

Spraying

a rule, useless against fungi, and vice versa. Bearing
in mind what has been said regarding the nature of
fungus attacks and insect attacks, it should be clear
that the time for spraying against fungi is often just
before an imminent attack, e.g. in the case of potato
blight (due to Phytophthora infestans) about July 10,
while for insects the time is the first onset of the
attack.

The best form for a spray is generally that of a
fine mist ; only rarely is it necessary or desirable
to apply a spray material so as to “‘ wash ”’ the plant
treated. Special machines have been devised for
the purpose of producing this type of spray. Its
formation depends mainly upon delivering the liquid
to be sprayed under sufficient pressure (generally
80 to 100 lb. to the square inch) through a suitable
nozzle which can be directed towards the thing
sprayed, and the direction of which can be easily
changed. A strong pump is therefore necessary,
and it is convenient if the material to be used can
be carried about in such a way as to be directly
available for the pump.

For large areas large machines and powerful
pumps are required, but for ordinary gardens the
machines of the knapsack type are most convenient.
Knapsack spraying machines are of two kinds, the
continuous pumping and the pneumatic. In the
former the pump is worked during the whole time
the sprayer isin operation; in the pneumatic, air is

144

Spraying
pumped in so as to get a pressure of 100-120 lb. to
the square inch upon the liquid in the container
before spraying is commenced. Both types of
machine are good, but with the pneumatic type
there is some danger of attempting to spray with
too little pressure, and there is also the need for
testing occasionally to ascertain that the machine
is sufficiently strong to withstand the necessary
pressure.

In any case the container should hold from three
to three and a half gallons of spray, and the machine
when charged should weigh about 40 lb. The
container may be made of copper unless lime-
sulphur is used, when it must be made of some
other metal not liable to be attacked by this com-
pound. It should be of a form to fit comfortably
upon the back, and have broad shoulder-straps of
such a length that the loaded machine will ride easily.
If of the continuous pumping type the pump handle
should come conveniently to the hand. In both
types all parts at all likely to get out of order should
be easily reached for adjustment ; the valves are
best of metal and the washers of leather. Leather
is generally preferable to rubber, for the latter is
more apt to perish. A supply of washers and spare
wearing parts should always be near at hand.

Means should be provided for ensuring that the
spray fluid is kept in a state of agitation during
spraying. This is less important when the machine

145 L

Spraying

is used and emptied immediately after being filled,
but if this is not done such heavy substances as
lead arsenate and Bordeaux mixture, where the
effective material is not in solution, but in a state of
suspension in water, are likely to settle and the
spray will then be delivered at unequal strengths,
and the work will be to a large extent ineffective.

The pump must be sufficiently powerful to give
the necessary pressure, and when spraying com-
mences several strokes of the pump should be given
before the tap leading to the delivery nozzle is
turned on.

The delivery nozzle is connected to the pump
by a length of flexible pipe which must be strong
and properly clamped on. By its means the nozzle
can be turned in various directions and all parts
of the plant covered in turn. The nozzle itself is
carried on the end of a metal tube and is one of the
most important parts of the machine. There are
many patterns, and the exit holes are of many types
and sizes according to the work the machine is
intended to do, delivering either a coarse spray
suitable for lime-washing or a very fine one suitable
for Bordeaux spraying. The fine type is most
generally useful. It must be easily cleaned, for some
of the substances used with it contain fine particles
which may sometimes clog it. As a further method
of preventing this it is necessary that the machine
should be supplied with a strainer, to prevent any

146

Spraying
large particles getting into it and finding their way
to the nozzle,

Where large trees have to be sprayed long lances
may be used to carry the nozzles’ to the desired
height.

Having filled the container and adjusted it upon
the back, secured the necessary pressure, turned on
the tap so that the mist-like spray is directed
towards the plant, see that all parts of it are covered,
the lower leaf-surface as well as the upper, continue
spraying just so long as is necessary to effect this,
then immediately cease.

Spray with the wind, but choose, asfar as possible,
calm weather for the operation. If rain, especially
heavy rain, falls after spraying for fungi and biting
insects the operation must be repeated. When
spraying with caustic soda (which must never be
used on leaves) protect the hands with leather
gloves. Spraying is best done in dull weather or in
the evening, not in bright sunshine.

Always cleanse the spraying machine and nozzle
after use and put away dry.

Unless provided with a special nozzle a syringe
is a very poor substitute for a spraying machine. It
cannot deliver the spray in a sufficiently fine state
to do efficient work.

Where powders such as flowers of sulphur have
to be distributed, powder bellows should be used go
as to get an even distribution. Little has been said

147 L2

Spraying

concerning dry spraying in this little book, for this
method of applying insecticides and fungicides is as
yet only in the experimental stage, and the results
secured from it are, while encouraging, not yet
sufficiently certain in most cases to warrant its
recommendation generally.

When spraying has to be done, see that suitable
materials are chosen, do it at the right time, do it
carefully, and do it thoroughly.

148

INDEX

Acer Pseudoplaitanus, black
blotches, 65

Acetylene, escape of, 31

Acidity, soil, 24, 26, 28

Actinomyces chromogenus, 93

Aims of plants, 2

Almond, gummy excretion, 65

Ammoniacal copper carbon-
ate, 62

Anemone coronaria, 92; sclero-
tia in roots of, 49, 66;
Puccinia pruni on, 54, 66,
92

Antirrhinum, spots on, 66

Ants, 108, 112, 129, 137

Aphides, 10, 26, 63, 67, 108, 113

Apples, 66-69 ; bitter-pitin, 39;
““mummy,”’ 50, 69; crown
gall, 66; canker, 50, 67

Arabis, rust, 69

Ascochyta clematidina, 16;
Pisi, 88, 94

Aspidistras, 114

Asters, mildew, 70; China, 73

Azalea indica, 70

Bacillus amylovorus, 90; sola-
nacearum, 94; tumefaciens,
66

Bacterium Hyacinthi, 81; twme-
faciens, 95

Barberry, Puccinia graminis on,

54,
Bark gnawed, 112
Beans, Broad, rust, 70; Dwarf
and Runner, spot, 70
Beet, rust, 71

Beetles, 108, 110, 111, 116,
126, 129, 136; mites, 141

Bibio, 116

Big-bud, 115

Bipalium kewense, 141

Birds, 103, 104, 110, 112, 136

Biting insects, symptoms pro-
duced by, 110

Bitter-pit, 39

Black moulds, 26

Bleeding, 38

Blisters in foliage, 111

Bordeaux mixture, 60

Borings, 111

Botrytis cinerea, 79, 84, 88, 90,
95, 99, 101; B. Paeoniae,
87; B. Galanthina, 98; B.
parasitica, 100

Breathing necessary to plants, 4

Bremia Lactucae, 83

Broomrape, 42

Buds, destruction of, 111

Burgundy mixture, 61

Burning, 31

Butterfly, cabbage, 118, 119,
124, 128

Cabbage, 71, 72; root maggot,
lil

Calceolaria, wilting of, 73

Callistephus hortensis, 73

Camellia, blotches on, 73

Camphor, 120

Canker, 50

Carbon bisulphide, 130

Carnations, 73-74; rust, 62,
73; smut, 50, 74; fly, 111

149

Index

Caterpillars, 108-135

Caustic wash, 135

Cecidomyidae, 141

Celery, 74; fly, 111, 125

Oercospora circumscissa, 65,
75; C. Melonis, 77, 84;
C. Resedae, 85

Chalk, powdered, for light soils,
27

Chemical constituents, 7, 32

Chenopodium album, 33

Cherry, 74, 75

Chickweed, 33

Chionodoxa, 75

Chlorosis, 33

Chrysanthemum, 75, 76, 111;
fly, 111, 125

Cineraria, 76

Oladosporium herbarum, 67;
C. Scabies, 78; C. carpo-
pene, 89; C. fuluum,
9

Clematis, 76

“Club,” 44, 48, 49, 63, 72

Coal-gas, escape of, 31

Cockchafers, 111, 116

Cockroaches, 108, 110, 129

Coleosportum Senecionis, 54,
76, 91

Colletotrichum — Lindemuthia-
num, 70; CO. malvacearum,

Coltsfoot, 28

Coniothyrium concentricum, 81;
C. Fuckelianum, 95

a as compounds, 59, 62

“ Coral-spot,” 53

Crane fly, 30

Crataegus, 77

Cress, 77

Criekets, 108, 110

Cronartium ribicolum, 54, 91

Cuckoo spit, 108, 113

Cucumber, 77

Curl, 39, 40, 47

Currants, ‘‘ coral-spot ’’ on, 53,
78; Black, spores on, 64,
55, 91; big-bud in, 115

Cystopus candidus, 69; C.
Tragopogonis, 97

Daddy-longlegs, 30, 108

Dablias and ‘‘ Sclerotium,”’ 69,
78

Dead parts, removal of, 57

Delphinium, 79

Dipping, suffocation by, 123

Dodder, 28, 42

Doubling, 41

Drainage, value of, 5, 26, 28,
29

“* Drawn.”’ plants, 35
Dusting, Sulphur-, 59

Earth-salts, 8, 10, 11, 17, 32,
34

Earwigs, 108, 112, 128, 137

Eggs, destruction of insect, 118;
prevention of egg-laying,
119, 121

Endophyllum Sempervivi, 98

Environment, best, 3

Hquisetum arvense, 28

Erica, 79

Erysiphe cichoracearum, 70, 77;
E. polygoni, 79, 88

Etiolation, causes of, 36

Excess of lime, 33; of water,
35; of fertilisers, 35

Exhaustion, plant, 20

Exoascus deformans, 65; E.
bullatus, 90; EH. Pruni,
92

Exobasidium japonicum,
E. Rhododendri, 95

Fat-hen, 33

Ferns, 114

Fig, 79

Firm planting, 9

Firs, Scots, fungus on needles,
54

Fish and flannel weed, 22; in
ornamental water, 105

Flannel weed, 21, 22, 105

Mlow ors: parts of, devoured,

Food making, 11, 17, 26, 36

Food storage, 17

Formalin treatment, 58

Frogs, 141

70;

150

Fruit, splitting of, 38; tun-
nelling in, 111; holing,
112

Fruit trees, “ canker’ of, 50

Fumigation, 59, 129

Fusarium, 73, 88; F. Pelar-
gonii, 90; F. Solani, 94

Fusicladium dendriticum, 68

Galls, 114

Gas lamps, fumes from, 30

Glazed pots, 29

Gloeosporium orbiculare, 78;
G. fructigenum, 79, 89; G.
rufomaculans, 101

Goat moth, 111

Gooseberry, hosts on, 54 ; mil-
dew, 80; picked green,
122

Goose-foot, 33

Grapes, burning, 31

Grass, effect of, on trees, 21

Grease bands, 127

Greenfly, 108, 113, 124

Ground beetles, 128, 138

Gymnosporangium clavarit-
forme, 77, 82; G. juni-
perinum, 82

Hand-picking, 124

Hares, 103

Heaths and lime, 27

Hellebore powder, 122, 132

Helleborus, 81

Heterosporium echinulatum, 74;
H. gracile, 82; H. varia-
bile, 98

Hollyhock rust, 62, 81

Honeydew, 26, 113

Horsetail, 28

Hover fly, 137

Hyacinth, 81 |

Hydrocyanic acid, 130

Hydrogen Peroxide treatment,
58 :

Ichneumons, 139
Infertility, curious cause of,

Insecticides, 132-135

Index

Insects, characteristics of, 106-
109; symptoms of, 110-
115; methods of dealing
with, 121

Iris rhizome rot, 63, 81

Juniper, 82

Lacewing fly, 137

Ladybirds, 136

Larch canker, 82

Laurel, 83

Lavatera trimestris, 83

Lawns, bare patches, 23 ; moss
and weeds, 23, 24

Lead arsenate, 121, 122, 127,
129, 132

Leaf-curl, 39, 40, 47, 112

ie jackets, 30, 111, 116,
31

Leaves, functions of, 11

Lettuce, 83

Libertella ulcerata, 79

Light, value of, 12, 36

Lily, 84

Lime, test for, 27; excess of, 33

Lime-sulphur, 134

Lime-sulphur-salt-soda, 135

Lime trees and honeydew, 26

Liquid manuring, 34

Liver of sulphur, 59, 134

Lizards, 141

London Purple, 132

Lychnis, 84

Lysol, 57

Malva, 84

Manufacturing districts, stand-
ing water in, 30

Manuring, liquid, 34

Mare’s-tail, 28

Marssonia Populi, 93

Mealy-bug, 125

Melampsora aecidioides, 93

Melon leaf spot, 84

Mice, 129, 131

Microsphaera Grossulariae, 80

Midge, swede and cabbage, 111

Mignonette, 85

Mildew, 39, 44-47, 53, 58

151

Index

Millepedes, 112, 128

Mint, rust of, 50, 85

Moles, 104, 141

Monilia fructigena, 69, 75

** Mosaic ’’ disease, 40

Moss on lawns, 23, 24

Moths, 111, 112; lackey, eggs
of, 118; codling attacking
apples, 122

Mottling, 40

Mucor subtilissimus, 86

Mycosphaerella brassicicola, 72 ;
M. cttrullina, 77

Mystrosporium adustum, 82

Naphthalene, 120

Napoleon III., mule pink, 20

Narcissus, 85

Nectarine, 89

Nectria ditissima, 50, 67; N.
cinnabarina, 78

Nettlo-leaf, 41

Nicotine sprays, 123 ; prepara-
tions, 129, 133

Nymphaea, 85

Oak, 86

Oidium chrysanthemr, 15
Olipidium Brassicae, 71
Onion, 86; maggot, 111
Orchids, syringing, 31
Otiorrhynchus, 125, 126, 129
Overcrowding, 36

Palms, 87, 114

Paraffin, 120, 121, 123, 128, 133

Parasitic insects, 139

Paris Green, 132

Parsley, 87

Parsnip, 87; fly, 111

Peach curl, 47, 65, 89

Pear, 89, 126, 135

Peas, 88

Pelargonium, 90

Peony, 86

Peronospora parasitica, 69, 101;
P. Schleideni, 86;
sparsa, 97; P. effusa, 98

Pestalozzia Guepini, 73

Peziza Willkommii, 83

Phosphorus paste, 129

Phragmidium Rubi-Idaei, 95 ;
P. subcorticium, 96

Phylloxera on vines, 115, 131

Phytophthora infestans, 93; P.
eryptogaea, 99

Pine, 91

Pinus Strobus, 54, 55

Planting, firmness in, 9

Plasmodiophora Brassicae, 72,
97

Plasmopara nivea, 87
Pleospora Oxyacanthae, 77
Plum trees, Puccinia pruni
on, 54
Plums, 91-93; ‘mummy,’ 50
Poa annua, 25; P. nemoralis,
5

2

Podosphaera leucotricha, 67;
P. Oxyacanthae, 77

Ponds, flannel weed on, 21, 22

Poplar, 93

Potash, value of, 32

Potassium sulphide, 59; per-
manganate, 62

Potato-blight, 52, 93, 94; leaf
curl, 39

Primrose, 94

Primula, 94

Pruning diseased parts, 57

Pseudomonas campestris, 72

Puccinia Pringsheimiana, 54,
66, 81; P. pruni, 54, 89,
92; P. graminis, 54, 71;
P. malvacearum, 81; P.
lychnidearum, 84; P. Men-
thae, 85; P. Vincae, 100;
P. Violae, 101

Pyridene, 121

Pythium De Baryanum, 71, 77

Quassia, 123, 134
Quicklime, powdered, 27

Rabbits, 103
Radish, 95

Ramularia Vallisumbrae, 85;
R. nymphaearum, 86
Raspberry, 95; moth, 111] ;

beetle grub, 112

152

Rats, 103, 129

Red spider, 31, 115

Rhododendron ferrugineum, 70

Rhododendrons, 27, 95

Rhytisma, 65

Roots, general functions of, 6 ;
destruction of, 111; tun-
nelling in, 111

Roses, 95, 96; mildew, 44-47 ;
rust, 62; galls, 115

Rotation of crops, 62

Rumex Acetosella, 28

Rusts, 53-55

Salsify, 97

Sawflies, 108, 112, 119, 122, 127

Saxifrage, 62, 97

Scab in apples, 68, 69

Scalding, 31

Scale insects, 108, 114

Scillas, 50, 97

Sclerotinia fructigena, 69

** Sclerotium disease,’’ 49, 66, 78

Scolytus, 129

Seakale, 97

Seed protection, 105

Sempervivum, 98

Senecto pulcher, 98

Septoria antirrhini, 66; S.
Dianthi, 74; S. Petrose-
lini, 74, 87; S. chrysan-
themi, 76; S. Populi, 93

Shaking, 126

Shanking, 37

Sheep sorrel, 28

Shepherd’s Purse, 20

Shot-hole fungi, 110

Silver leaf, 50, 53, 89, 92

Slow-worms, 141

Blogs. 110, 112, 116, 117, 124,

127

Snails, 110, 117, 124

Snowdrop, 98

Soap, soft, 123, 183, 134

Soda, caustic, 118

Soda-Bordeaux mixture, 61-

Soft-soap-sulpbur dip, 134

Soil, Hao constituents of,

7; acidity, 24, 26, 28
Sour soils, 24, 25, 28

Index

Spergula arvensis, 28

Sphaerella Fragariae, 99

Sphaeropsis malorum, 67

Sphaerotheca Mors-uvae, 80;
S. pannosa, 83, 96; 8S.
Humuli, 99

Spiders, 141

Spinach, 98

Splitting, 38

Spongospora subterranea, 93

Spore distribution, 43-55

“Spotting,” 31, 34

Spraying, 58-62, 121, 143

Spurrey, 28

Stem structure, 9

Stereum purpureum, 50, 92

Stock, 98

Strawberries, 98, 128

Sucking insects, 113

Sulphur-dusting, 59 ;
tion, 59

Sweet Pea, 99

Sycamore, black blotches on
leaf-tissue, 65

Synchytrium endobioticum, 94

fumiga-

Taphrina aurea, 93

Tar, Stockholm or gas, 57

Temperature, best, 6

Thielavia basicola, 88

Thrips, 108, 115

Toads, 141

Tomato, 99; moth, 112

Toothwort, 42

Trapping, 127-129

Trees, effect of grass on, 21 ;
best grass to grow under,
25; fungus on Scots firs,
54; large boring cater-
pillars in, 129; lime-wash
for, 135

Tulips, fire in, 49, 100

Turnip,100; flea beetle, 116,117

Tussilago Farfara, 28

Uromyces Fabae, 70; U. Betae,
71; U. caryophyllinus, 73;
U. Scillarum, 97

Ustilago violacea, 74, 84; U,.
Vailiantii, 75, 97

153

Index

Variegation, 40

Venturia inaequalis, 68; V.
pirina, 90

Veratrum album, 132

Verbascum, 100

Vinca, 100

Vines, 100, 117

Viola, 101

Wallflower, 101

Warted foliage, 37, 49

Wasps, 108, 112, 131, 137

Watering, 14, 15

Water Lilies, smothered by
“flannel weed,” 21

Weeds, of sour soils, 28;
harbouring fungus, 57
Weevil grubs, 111, 112, 117, 125

Wheat, red rust of, 54

Winter, fungi in, 50

Wireworms, 111, 116, 125, 128,
131, 138

Wood leopard, 111

Woodlice, 110, 128

Woolly aphis, 63, 67, 125

Worms, 141

Wounding plants, 57; trees,
103, 104

Xyleborus, 129

THE END

Printed by R. & R. Crarx, Limitep, Edinburgh.

“Country Life” Library of Garden Books

GARDENING FOR BEGINNERS : A Handbook to the Garden.
By E. T. Cook. Coloured Plates and over 200 Illustrations, Plans
and Diagrams from Photographs of selected specimens of Plants,
Flowers, Trees, Shrubs, Fruits, etc. Seventh Edition. 17s. 6d.
net ; by post 18s. 6d.

“One cannot speak in too high praise of the idea that led Mr. E. T.
Cook to compile this Gardening for Beginners. Nothing is omitted.”
—Morning Post.

COLOUR SCHEMES FOR THE FLOWER GARDEN. By
GERTRUDE JEKYLL. Fourth Edition, revised. 15s. net; by
post 15s. 6d.

WALL AND WATER GARDENS. With Chapters on the Rock
Garden, the Heath Garden and the Paved Water Garden. By
GERTRUDE JEKYLL. Sixth Edition, revised. Large 8vo, 220
pages. 17s. 6d. net; by post 18s. 4d.

‘*He who will consent to follow Miss Jekyll aright will find that
under her guidance the old walls, the stone steps, the rockeries, the
ponds, or streamlets of his garden will presently blossom with all kinds
of flowers undreamed of, and become marvels of varied foliage.”—
Times.

TREES AND SHRUBS FOR ENGLISH GARDENS. By E. T.
Cook. 15s. 8d. net; by post 16s. 5d.

‘*It contains a mass of instruction and illustration not always to be
found altogether when required, and as such it will be very useful as a
popular hand-book for amateurs and others anxious to grow trees and
shrubs.” —/eld.

THE PLANNING AND PLANTING OF LITTLE GARDENS.
By GrorGE DILLISTONE. With Notes and Criticisms by Sir
Lawrence WEAVER. Freely illustrated. 6s. net; by post

6s. 6d.

ANNUALS AND BIENNIALS. The best Annual and Biennial
Plants and their uses in the Garden. By GERTRUDE JEKYLL.
With cultural notes by E. H. Jenxrns, Illustrated throughout.
Qs, 5d. net; by post 9s. 11d.

“A noteworthy addition to the special literature of the garden.”—

The Scotsman.
I

“ Country Life” Library of Garden Books

(continued)

HENRY NICHOLSON ELLACOMBE: A Memoir. By ARTHUR
W. HILL. 10s. 6d. net; by post 11s.

THE DISEASES OF TREES. By Professor R. Hartic. Royal
8vo. 13s, 2d. net; by post 13s. 6d.

SEASIDE PLANTING OF TREES AND SHRUBS. By ALFRED
GauT, F.R.H.S. 6s, 3d. net; by post 6s. 9d.

TULIPS AND DAFFODILS. By the Rev. JosepH Jacoz. (ln
the Press.)

THE BOOK OF BRITISH FERNS. By Cuar.es T. DRUERY,
F.L.S. 4s, 5d. net; by post 4s, 9d.

THE HARDY FLOWER BOOK. By E. H. JEeNKrns. 50 Illustrations
and Coloured Frontispiece, 2nd Edition. 3s. 2d. net; by post 3s.6d.

‘‘The amateur gardener who covets success should read Zhe Hardy
Flower Book.” —Daily Mail,

THE ROCK GARDEN. By E. H. Jenkins, 2nd Edition. 7s. 6d.
net ; by post 8s.

PERPETUAL CARNATIONS ILLUSTRATED. By Laurence
J. Cook. 2s. 6d. net; by post 3s.

GARDENING MADE EASY. By E. T. Coox. 200 pages and
23 Illustrations. 2s, net; Cloth, 3s.; postage 3d. extra.

“The A.B.C. of Gardening.” —Scotsman.

ROSE GROWING MADE EASY. By E. T. Cook. 1s, 3d. net.
Cloth, 2s, net ; postage 3d. extra.

‘“*, . . Ought to be in the hands of every rose grower.” —Adberdeen
Free Press.

FRUIT GROWING FOR BEGINNERS. By F. W. Harvey.
2s. 6d. net ; postage 6d. extra.
“An amazing amount of information is packed into this book,”—

Evening News.
2