Egypt, where a similar scale was damaging the fig trees and other
valuable plants, and the result was again the same, the injurious
insects were destroyed. This was achieved only after extensive
correspondence and several failures. The active agent in Alexandria was
Rear Admiral Blomfield, of the British Royal Navy, a man apparently of
wide information, good judgment, and great energy.
The same thing occurred when the California people sent this saviour of
horticulture to South Africa, where the white scale had also made its
appearance.
It is not only beneficial insects, however, which are being imported,
but diseases of injurious insects. In South Africa the colonists suffer
severely from swarms of migratory grasshoppers, which fly from the north
and destroy their crops. They have discovered out there a fungus
disease, which under favorable conditions kills off the grasshoppers in
enormous numbers. At the Bacteriological Institute in Grahamstown,
Natal, they have cultivated this fungus in culture tubes, and have
carried it successfully throughout the whole year; and they have used it
practically by distributing these culture tubes wherever swarms of
grasshoppers settle and lay their eggs. The disease, once started in an
army of young grasshoppers, soon reduces them to harmless numbers. The
United States Government last year secured culture tubes of this
disease, and experiments carried on in Colorado and in Mississippi show
that the vitality of the fungus had not been destroyed by its long ocean
voyage, and many grasshoppers were killed by its spread. During the past
winter other cultures were brought over from Cape Colony, and the fungus
is being propagated in the Department of Agriculture for distribution
during the coming summer in parts of the country where grasshoppers may
prove to be destructively abundant.
[Illustration: Grasshopper dying from Fungus Disease]
Although we practically no longer have those tremendous swarms of
migratory grasshoppers which used to come down like devastating armies
in certain of our Western States and in a night devour everything green,
still, almost every year, and especially in the West and South, there
is somewhere a multiplication of grasshoppers to a very injurious
degree, and it is hoped that the introduced fungus can be used in such
cases.
Persons officially engaged in searching for remedies for injurious
insects all over the world have banded themselves together in a society
known as the Association of Economic Entomologists. They are constantly
interchanging ideas regarding the destruction of insects, and at present
active movements are on foot in this direction of interchanging
beneficial insects. Entomologists in Europe will try the coming summer
to send to the United States living specimens of a tree-inhabiting
beetle which eats the caterpillar of the gipsy moth, and which will
undoubtedly also eat the caterpillar so common upon the shade-trees of
our principal Eastern cities, which is known as the Tussock moth
caterpillar. An entomologist from the United States, Mr. C. L. Marlatt,
has started for Japan, China, and Java, for the purpose of trying to
find the original home of the famous San Jose scale--an insect which has
been doing enormous damage in the apple, pear, peach, and plum orchards
of the United States--and if he finds the original home of this scale,
it is hoped that some natural enemy or parasite will be discovered which
can be introduced into the United States to the advantage of our
fruit-growers. Professor Berlese of Italy, and Dr. Reh, of Germany,
will attempt the introduction into Europe of some of the parasites of
injurious insects which occur in the United States, and particularly
those of the woolly root-louse of the apple, known in Europe as the
"American blight"--one of the few injurious insects which probably went
to Europe from this country, and which in the United States is not so
injurious as it is in Europe.
It is a curious fact, by the way, that while we have had most of our
very injurious insects from Europe, American insects, when accidentally
introduced into Europe, do not seem to thrive. The insect just
mentioned, and the famous grape-vine _Phylloxera_, a creature which
caused France a greater economic loss than the enormous indemnity which
she had to pay to Germany after the Franco-Prussian War, are practically
the only American insects with which we have been able to repay Europe
for the insects which she has sent us. Climatic differences, no doubt,
account for this strange fact, and our longer and warmer summers are the
principal factor.
It is not alone the parasitic and predaceous insects which are
beneficial. A new industry has been brought into the United States
during the past two years by the introduction and acclimatization of the
little insect which fertilizes the Smyrna fig in Mediterranean
countries. The dried-fig industry in this country has never amounted to
anything. The Smyrna fig has controlled the dried-fig markets of the
world, but in California the Smyrna fig has never held its fruit, the
young figs dropping from the trees without ripening. It was found that
in Mediterranean regions a little insect, known as the _Blastophaga_,
fertilizes the flowers of the Smyrna fig with pollen from the wild fig
which it inhabits. The United States Department of Agriculture in the
spring of 1899 imported successfully some of these insects through one
of its travelling agents, Mr. W. T. Swingle, and the insect was
successfully established at Fresno in the San Joaquin Valley. A
far-sighted fruit-grower, Mr. George C. Roeding, of Fresno, had planted
some years previously an orchard of 5,000 Smyrna fig trees and wild fig
trees, and his place was the one chosen for the successful experiment.
The little insect multiplied with astonishing rapidity, was carried
successfully through the winter of 1899-1900, and in the summer of 1900
was present in such great numbers that it fertilized thousands of figs,
and fifteen tons of them ripened. When these figs were dried and packed
it was discovered that they were superior to the best imported figs.
They contained more sugar and were of a finer flavor than those brought
from Smyrna and Algeria. The _Blastophaga_ has come to stay, and the
prospects for a new and important industry are assured.
With all these experiments the criticism is constantly made that
unwittingly new and serious enemies to agriculture may be introduced.
The unfortunate introduction of the English sparrow into this country is
mentioned, and the equally unfortunate introduction of the East Indian
mongoose into the West Indies as well. The fear is expressed that the
beneficial parasitic insects, after they have destroyed the injurious
insects, will either themselves attack valuable crops or do something
else of an equally harmful nature. But there is no reason for such
alarm. The English sparrow feeds on all sorts of things, and the East
Indian mongoose, while it was introduced into Jamaica to kill snakes,
was found, too late, to be also a very general feeder. As a matter of
fact, after the snakes were destroyed, and even before, it attacked
young pigs, kids, lambs, calves, puppies, and kittens, and also
destroyed bananas, pineapples, corn, sweet potatoes, cocoanuts, peas,
sugar corn, meat, and salt provisions and fish. But with the parasitic
and predatory insects the food habits are definite and fixed. They can
live on nothing but their natural food, and in its absence they die. The
Australian ladybird originally imported, for example, will feed upon
nothing but scale insects of a particular genus, and, as a matter of
fact, as soon as the fluted scales became scarce the California
officials had the greatest difficulty in keeping the little beetles
alive, and were actually obliged to cultivate for food the very insects
which they were formerly so anxious to wipe out of existence! With the
_Scutellista_ parasite the same fact holds. The fly itself does not
feed, and its young feed only upon certain scale insects, and so with
all the rest.
All of these experiments are being carried on by men learned in the ways
of insects, and only beneficial results, or at the very least negative
ones, can follow. And even where only one such experiment out of a
hundred is successful, what a saving it will mean!
We do not expect the time to come when the farmer, finding Hessian fly
in his wheat, will have only to telegraph the nearest experiment
station, "Send at once two dozen first-class parasites;" but in many
cases, and with a number of different kinds of injurious insects,
especially those introduced from foreign countries, it is probable that
we can gain much relief by the introduction of their natural enemies
from their original home.
THE STRANGE STORY OF THE FLOWERS
GEORGE ILES
[From "The Wild Flowers of America," copyright by G. H. Buek
& Co., New York, 1894, by their kind permission. The American
edition is out of print: the Canadian edition, "Wild Flowers
of Canada," is published by Graham & Co., Montreal, Canada.
The work describes and illustrates in their natural tints
nearly three hundred beautiful flowers.]
Imagine a Venetian doge, a French crusader, a courtier of the time of
the second Charles, an Ojibway chief, a Justice of the Supreme Court, in
the formal black of evening dress, and how much each of them would lose!
Where there is beauty, strength or dignity, dress can heighten it; where
all these are lacking, their absence is kept out of mind by raiment in
itself worthy to be admired. If dress artificial has told for much in
the history of human-kind, dress natural has told for yet more in the
lesser world of plant and insect life. In some degree the tiny folk that
reign in the air, like ourselves, are drawn by grace of form, by charm
of colour; of elaborate display of their attractions moths, butterflies
and beetles are just as fond as any belles of the ball-room. Now let us
bear in mind that of all the creatures that share the earth with man,
the one that stands next to him in intelligence is neither a biped nor
a quadruped, but that king of the insect tribe, the ant, which can be a
herdsman and warehouse-keeper, an engineer and builder, an explorer and
a general. With all his varied powers the ant lacks a peculiarity in his
costume which has denied him enlistment in a task of revolution in which
creatures far his inferiors have been able to change the face of the
earth. And the marvel of this peculiarity of garb which has meant so
much, is that it consists in no detail of graceful outline, or beauty of
tint, but solely in the minor matter of texture. The ant, warrior that
he is, wears smooth and shining armour; the bee, the moth and the
butterfly are clad in downy vesture, and simply because thus enabled to
catch dust on their clothes these insects, as weavers of the web of
life, have counted for immensely more than the ant with all his brains
and character. To understand the mighty train of consequences set in
motion by this mere shagginess of coat, let us remember that, like a
human babe, every flowering plant has two parents. These two parents,
though a county's breadth divide them, are wedded the instant that
pollen from the anther of one of them meets the stigma of the other.
Many flowers find their mates upon their own stem; but, as in the races
of animals, too close intermarriage is hurtful, and union with a distant
stock promotes both health and vigor. Hence the great gain which has
come to plants by engaging the wind as their matchmaker--as every
summer shows us in its pollen-laden air, the oaks, the pines, the
cottonwoods, and a host of other plants commit to the breeze the winged
atoms charged with the continuance of their kind. Nevertheless, long as
the wind has been employed at this work, it has not yet learned to do it
well; nearly all the pollen entrusted to it is wasted, and this while
its production draws severely upon the strength of a plant. As good
fortune will have it, a great many flowers close to their pollen yield
an ample supply of nectar: a food esteemed delicious by the whole round
of insects, winged and wingless. While ants might sip this nectar of
ages without plants being any the better or the worse; a very different
result has followed upon the visits of bees, wasps, and other
hairy-coated callers. These, as they devour nectar, dust themselves with
the pollen near by. Yellowed or whitened with this freightage, moth and
butterfly, as they sail through the air, know not that they are
publishing the banns of marriage between two blossoms acres or, it may
be, miles apart. Yet so it is. Alighting on a new flower the insect rubs
a pollen grain on a stigma ready to receive it, and lo! the rites of
matrimony are solemnized then and there. Unwittingly the little visitor
has wrought a task bigger with fate than many an act loudly trumpeted
among the mightiest deeds of men! On the threshold of a Lady's Slipper a
bee may often be detected in the act of entrance. In the Sage-flower he
finds an anther of the stamen which, pivoted on its spring, dusts him
even more effectually.
[Illustration: Sage-flower and Bee]
Bountifully to spread a table is much, but not enough, for without
invitation how can hospitality be dispensed? To the feast of nectar the
blossoms join their bidding; and those most conspicuously borne and
massed, gayest of hue, richest in odor, secure most guests, and are
therefore most likely to transmit to their kind their own excellences as
hosts and entertainers. Thus all the glories of the blossoms have arisen
in doing useful work; their beauty is not mere ornament, but the sign
and token of duty well performed. Our opportunity to admire the radiancy
and perfume of a jessamine or a pond-lily is due to the previous
admiration of uncounted winged attendants. If a winsome maid adorns
herself with a wreath from the garden, and carries a posy gathered at
the brookside, it is for the second time that their charms are impressed
into service; for the flowers' own ends of attraction all their scent
and loveliness were called into being long before.
Let us put flowers of the blue flag beside those of the maple, and we
shall have a fair contrast between the brilliancy of blossoms whose
marrier has been an insect, and the dinginess of flowers indebted to the
services of the wind. Can it be that both kinds of flowers are descended
from forms resembling each other in want of grace and colour? Such,
indeed, is the truth. But how, as the generations of the flowers
succeeded one another, did differences so striking come about? In our
rambles afield let us seek a clue to the mystery. It is late in
springtime, and near the border of a bit of swamp we notice a clump of
violets: they are pale of hue, and every stalk of them rises to an
almost weedy height.
[Illustration: Wild Rose, Single]
Twenty paces away, on a knoll of dry ground, we find more violets, but
these are in much deeper tints of azure and yellow, while their stalks
are scarcely more than half as tall as their brethren near the swamp.
Six weeks pass by. This time we walk to a wood-lot close to a brimming
pond. At its edge are more than a score wild-rose bushes. On the very
first of them we see that some of the blossoms are a light pink, others
a pink so deep as to seem dashed with vivid red. And while a flower here
and there is decidedly larger and more vigorous than its fellows, a few
of the blossoms are undersized and puny: the tide of life flows high and
merrily in a fortunate rose or two, it seems to ebb and falter by the
time it reaches one or two of their unhappy mates. As we search bush
after bush we are at last repaid for sundry scratches from their thorns
by securing a double rose, a "sport," as the gardener would call it. And
in the broad meadow between us and home we well know that for the quest
we can have not only four-leaved clovers, but perchance a handful of
five and six-leaved prizes. The secret is out. Flowers and leaves are
not cast like bullets in rigid moulds, but differ from their parents
much as children do. Usually the difference is slight, at times it is as
marked as in our double rose. Whenever the change in a flower is for the
worse, as in the sickly violets and roses we have observed, that
particular change ends there--with death. But when the change makes a
healthy flower a little more attractive to its insect ministers, it will
naturally be chosen by them for service, and these choosings, kept up
year after year, and century upon century, have at last accomplished
much the same result as if the moth, the bee, and the rest of them had
been given power to create blossoms of the most welcome forms, the most
alluring tints, the most bewitching perfumes.
In farther jaunts afield we shall discover yet more. It is May, and a
heavy rainstorm has caused the petals of a trillium to forget
themselves and return to their primitive hue of leafy green. A month
later we come upon a buttercup, one of whose sepals has grown out as a
small but perfect leaf. Later still in summer we find a rose in the same
surprising case, while not far off is a columbine bearing pollen on its
spurs instead of its anthers. What family tie is betrayed in all this?
No other than that sepals, petals, anthers and pistils are but leaves in
disguise, and that we have detected nature returning to the form from
which ages ago she began to transmute the parts of flowers in all their
teeming diversity. The leaf is the parent not only of all these but of
delicate tendrils, which save a vine the cost of building a stem stout
enough to lift it to open air and sunshine. However thoroughly, or
however long, a habit may be impressed upon a part of a plant, it may on
occasion relapse into a habit older still, resume a shape all but
forgotten, and thus tell a story of its past that otherwise might remain
forever unsuspected. Thus it is with the somewhat rare "sport" that
gives us a morning glory or a harebell in its primitive form of unjoined
petals. The bell form of these and similar flowers has established
itself by being much more effective than the original shape in dusting
insect servitors with pollen. Not only the forms of flowers but their
massing has been determined by insect preferences; a wide profusion of
blossoms grow in spikes, umbels, racemes and other clusters, all
economizing the time of winged allies, and attracting their attention
from afar as scattered blossoms would fail to do. Besides this massing,
we have union more intimate still as in the dandelion, the sun-flower
and the marigold. These and their fellow composites each seem an
individual; a penknife discloses each of them to be an aggregate of
blossoms. So gainful has this kind of co-operation proved that
composites are now dominant among plants in every quarter of the globe.
As to how composites grew before they learned that union is strength, a
hint is dropped in the "sport" of the daisy known as "the hen and
chickens," where perhaps as many as a dozen florets, each on a stalk of
its own, ray out from a mother flower.
While for the most part insects have been mere choosers from among
various styles of architecture set before them by plants, they have
sometimes risen to the dignity of builders on their own account, and
without ever knowing it. The buttress of the larkspur has sprung forth
in response to the pressure of one bee's weight after another, and many
a like structure has had the very same origin,--or shall we say,
provocation? In these and in other examples unnumbered, culminating in
the marvellous orchids and their ministers, there has come about the
closest adaptation of flower-shape to insect-form, the one now clearly
the counterpart of the other.
We must not forget that the hospitality of a flower is after all the
hospitality of an inn-keeper who earns and requires payment. Vexed as
flowers are apt to be by intruders that consume their stores without
requital, no wonder that they present so ample an array of repulsion and
defence. Best of all is such a resource as that of the red clover, which
hides its honey at the bottom of a tube so deep that only a friendly
bumblebee can sip it. Less effective, but well worth a moment's
examination, are the methods by which leaves are opposed as fences for
the discouragement of thieves. Here, in a Bellwort, is a perfoliate leaf
that encircles the stem upon which it grows; and there in a Honeysuckle
is a connate leaf on much the same plan, formed of two leaves, stiff and
strong, soldered at their bases. Sometimes the pillager meets prickles
that sting him, as in the roses and briers; and if he is a little fellow
he is sure to regard him with intense disgust, a bristly guard of wiry
hair--hence the commonness of that kind of fortification. Against
enemies of larger growth a tree or shrub will often aim sharp
thorns--another piece of masquerade, for thorns are but branches checked
in growth, and frowning with a barb in token of disappointment at not
being able to smile in a blossom. In every jot and tittle of barb and
prickle, of the glossiness which disheartens or the gumminess which
ensnares, we may be sure that equally with all the lures of hue, form
and scent, nothing, however trifling it may seem, is as we find it,
except through usefulness long tested and approved. In flowers, much
that at first glance looks like idle decoration, on closer scrutiny
reveals itself as service in disguise. In penetrating these disguises
and many more of other phases, the student of flowers delights to busy
himself. He loves, too, to detect the cousinship of plants through all
the change of dress and habit due to their rearing under widely
different skies and nurture, to their being surrounded by strangely
contrasted foes and friends. Often he can link two plants together only
by going into partnership with a student of the rocks, by turning back
the records of the earth until he comes upon a flower long extinct, a
plant which ages ago found the struggle for life too severe for it. He
ever takes care to observe his flowers accurately and fully, but chiefly
that he may rise from observation to explanation, from bare facts to
their causes, from declaring What, to understanding, Whence and How.
One of the stock resources of novelists, now somewhat out of date, was
the inn-keeper who beamed in welcome of his guest, grasped his hand in
gladness, and loaded a table for him in tempting array, and all with
intent that later in the day (or night) he might the more securely
plunge a dagger into his victim's heart--if, indeed, he had not already
improved an opportunity to offer to that victim's lips a poisoned cup.
This imagined treachery might well have been suggested by the behaviour
of certain alluring plants that so far from repelling thieves, or
discouraging pillagers, open their arms to all comers--with purpose of
the deadliest. Of these betrayers the chief is the round-leaved sun-dew,
which plies its nefarious vocation all the way from Labrador to Florida.
Its favourite site is a peat-bog or a bit of swampy lowland, where in
July and August we can see its pretty little white blossoms beckoning to
wayfaring flies and moths their token of good cheer! Circling the
flower-stalk, in rosette fashion, are a dozen or more round leaves, each
of them wearing scores of glands, very like little pins, a drop of gum
glistening on each and every pin by way of head. This appetizing gum is
no other than a fatal stick-fast, the raying pins closing in its aid the
more certainly to secure a hapless prisoner. Soon his prison-house
becomes a stomach for his absorption. Its duty of digestion done, the
leaf in all seeming guilessness once more expands itself for the
enticement of a dupe. To see how much the sun-dew must depend upon its
meal of insects we have only to pull it up from the ground. A touch
suffices--it has just root enough to drink by; the soil in which it
makes, and perhaps has been obliged to make, its home has nothing else
but drink to give it.