DISEASES AND INSECTS ATTACKING THE ROSE.
Brave Rose, alas, whose art thou? In thy chair
Where thou didst lately so triumph and shine
A worm doth sit, whose many feet and hair
Are the more foul the more thou art divine.
This, this hath done it; this did bite the root
And bottom of the leaves, which, when the wind
Did once perceive, it blew them under foot,
Where rude, unhallow'd steps do crush and grind
Their beauteous glories. Only shreds of thee,
And those all bitten, in thy chair I see.
HERBERT.
The diseases to which the Rose is liable are generally owing either
to the presence of various Cryptogamic plants, or to the attacks of
certain insects whose larvæ are supported at the expense of the plant.
Among Cryptogamic parasites which have been observed upon rose-bushes,
and which infest chiefly the Provence and other rough-leaved roses,
the following are the most troublesome:
Rust.--The rust, when examined by a magnifier, is found to consist
of minute yellow spots, each of which is a fungus, _Lecythea Rosæ_.
It is common and injurious to roses, as it frequently covers all the
leaves. The most effectual mode of preventing its spreading is to cut
off with care and burn all the infected branches, which will sometimes
render necessary the destruction of the whole plant.
Mildew.--The minute fungus which produces mildew is called by
botanists _Sphærotheca pannosa_. It appears like a gray mould on the
smaller stems and blistered leaves. It is a very troublesome enemy to
the Rose, and will sometimes put at defiance every application for its
destruction. The most effectual is smoking with sulphur, dusting with
dry flowers of sulphur, or syringing with sulphur water. The former
should only be practiced by a skillful hand, as too much sulphur-smoke
will sometimes entirely kill the plant.
Mould is due to a minute gray fungus, _Peronospora sparsa_, and
manifests its presence by the appearance of irregular pale brownish
spots upon the upper surface of the leaf. Upon the under surface of
these spots the mould will be found.
Other species of fungi attack the Rose, but they are not sufficiently
troublesome to the cultivator to need enumeration here.
The _insects_ which infest the Rose are quite numerous, and their
attacks are more or less injurious. The majority of those which are
found on the plant in the state of perfect insects are comparatively
harmless. The most injurious are those whose larvæ feed on the leaves
and pith of the trunk and limbs, and thus destroy the plant; while
the perfect insect, like the Green-fly, will simply stop the growth
and impair the health of the tree, by fastening upon the green and
tender bark of the young shoots, and devouring the sap. It is highly
desirable that amateur cultivators should devote more time to the
study of Entomology, for upon an intimate acquaintance with the
habits of these minute depredators depends, in a greater degree than
is generally supposed, the success of cultivation. Our own leisure
is so limited, that we have been able to devote very little time
to this subject; and we can find no work that treats in detail the
insects that attack the Rose. We simply give some account of the
most troublesome ones drawn mainly from Harris' Insects Injurious to
Vegetation.
Green-Fly, or Plant-Louse.--_Aphis Rosæ._--This very common
insect is a scourge to roses, from the facility of its reproduction,
and its numerous progeny sometimes entirely cover the leaves, the
young sprouts, and the flower buds. Devouring the sap, they are very
injurious, and, when numerous, sometimes destroy the plant, while
they soil every part on which they collect. The most common species
is of a pale green, but there is a variety of a dingy yellow. Many
are destroyed by small birds, but they have other enemies, as the
larvæ of the _Coccinellas_, or Lady-birds, and other insects destroy
large numbers. The first eggs of the Green-fly are deposited in the
autumn, at the base of the buds, and are hatched in the early part
of the following spring. Generation after generation is then rapidly
produced, numbering sometimes eight or ten before autumn. These are
produced alive, and without the intervention of the male. Reaumur
estimated that a single Aphis might produce six thousand millions in
one summer. The first hatching can be prevented by washing the plant
with soft soap and water, or with whale-oil soap, before the buds
commence swelling. When the plant is infested with them, it can be
washed with tobacco-water and then rinsed in clean water. If in a
house, fumigation with tobacco is better. An English writer recommends
washing in a decoction of an ounce of quassia to a quart of water, as
a very effective and safe remedy. Fumigation is, however, the must
thoroughly searching remedy, and can be easily applied to plants in
the open air, by means of an empty barrel inverted over the plant, and
a pan of burning tobacco.
Gall-Flies.--Several species of _Cynips_, or Gall-flies, attack the
rose, their punctures, made for the purpose of depositing their eggs,
being followed by variously formed excrescences containing the larvæ.
The Bedeguars, formed by the puncture of the _Cynips Rosæ_, were
formerly employed in medicine as astringents. Harris enumerates the
American species as follows:
_Cynips bicolor._--"Round, prickly galls, of a reddish color, and
rather larger than a pea, may often be seen on rose-bushes. Each of
them contains a single grub, and this in due time turns to a gall-fly.
Its head and thorax are black, and rough with numerous little pits;
its hind-body is polished, and, with the legs, of a brownish-red
color. It is a large insect compared with the size of its gall,
measuring nearly one-fifth of an inch in length, while the diameter of
its gall, not including the prickles, rarely exceeds three-tenths of
an inch."
_Cynips dichlocerus_, "or the gall-fly with two-colored antennæ, is
of a brownish-red or cinnamon color, with four little longitudinal
grooves on the top of the thorax, the lower part of the antennæ red,
and the remainder black. It varies in being darker sometimes, and
measures from one-eighth to three-sixteenths of an inch in length.
Great numbers of these gall-flies are bred in the irregular woody
galls, or long excrescences, of the stems of rose-bushes."
_Cynips semipiceus._--"The small roots of rose-bushes, and of other
plants of the same family, sometimes produce rounded, warty, and woody
knobs, inhabited by numerous gall-insects, which, in coming out,
pierce them with small holes on all sides. The winged insects closely
resemble the dark varieties of the preceding species in color, and in
the little furrows on the thorax; but their legs are rather paler, and
they do not measure more than one-tenth of an inch in length."
Rose-Slug, _Selandria Rosæ_, of Harris, who gives the following
account: "The saw-fly of the rose, which, as it does not seem to
have been described before, may be called _Selandria Rosæ_, from its
favorite plant, so nearly resembles the slug-worm saw-fly as not to
be distinguished therefrom except by a practiced observer. It is
also very much like _Selandria barda_, _Vitis_, and _pygmæa_, but
has not the red thorax of these three closely allied species. It is
of a deep and shining black color. The first two pairs of legs are
brownish-gray or dirty white, except the thighs, which are almost
entirely black. The hind legs are black, with whitish knees. The wings
are smoky, and transparent, with dark brown veins, and a brown spot
near the middle of the edge of the first pair. The body of the male
is a little more than three-twentieths of an inch long, that of the
female one-fifth of an inch or more, and the wings expand nearly or
quite two-fifths of an inch. These saw-flies come out of the ground
at various times between the twentieth of May and the middle of June,
during which period they pair and lay their eggs. The females do not
fly much, and may be seen, during most of the day, resting on the
leaves; and, when touched, they draw up their legs, and fall to the
ground. The males are more active, fly from one rose-bush to another,
and hover around their sluggish partners. The latter, when about to
lay their eggs, turn a little on one side, unsheathe their saws, and
thrust them obliquely into the skin of the leaf, depositing in each
incision thus made, a single egg. The young begin to hatch in ten
days or a fortnight after the eggs are laid. They may sometimes be
found on the leaves as early as the first of June, but do not usually
appear in considerable numbers until the twentieth of the same month.
How long they are in coming to maturity, I have not particularly
observed; but the period of their existence in the caterpillar state
probably does not exceed three weeks. They somewhat resemble the
young of the saw-fly in form, but are not quite so convex. They have
a small, round, yellowish head, with a black dot on each side of it,
and are provided with twenty-two short legs. The body is green above,
paler at the sides, and yellowish beneath; and it is soft, and almost
transparent like jelly. The skin of the back is transversely wrinkled,
and covered with minute elevated points; and there are two small,
triple-pointed warts on the edge of the first ring, immediately behind
the head. These gelatinous and sluggish creatures eat the upper
surface of the leaf in large irregular patches, leaving the veins and
the skin beneath untouched; and they are sometimes so thick that not a
leaf on the bushes is spared by them, and the whole foliage looks as
if it had been scorched by fire, and drops off soon afterward. They
cast their skins several times, leaving them extended and fastened on
the leaves; after the last moulting they lose their semi-transparent
and greenish color, and acquire an opaque yellowish hue. They then
leave the rose-bushes, some of them slowly creeping down the stem,
and others rolling up and dropping off, especially when the bushes
are shaken by the wind. Having reached the ground, they burrow to the
depth of an inch or more in the earth, where each one makes for itself
a small oval cell, of grains of earth, cemented with a little gummy
silk. Having finished their transformations, and turned to flies,
within their cells, they come out of the ground early in August, and
lay their eggs for a second brood of young. These, in turn, perform
their appointed work of destruction in the autumn; they then go into
the ground, make their earthy cells, remain therein throughout the
winter, and appear in the winged form, in the following spring and
summer.
"During several years past, these pernicious vermin have infested the
rose-bushes in the vicinity of Boston, and have proved so injurious
to them, as to have excited the attention of the Massachusetts
Horticultural Society, by whom a premium of one hundred dollars for
the most successful mode of destroying these insects was offered
in the summer of 1840. About ten years ago, I observed them in
gardens in Cambridge, and then made myself acquainted with their
transformations. At that time they had not reached Milton, my former
place of residence, and have appeared in that place only within
two or three years. They now seem to be gradually extending in all
directions, and an effectual method for preserving our roses from
their attacks has become very desirable to all persons who set any
value on this beautiful ornament of our gardens and shrubberies.
Showering or syringing the bushes with a liquor, made by mixing with
water the juice expressed from tobacco by tobacconists, has been
recommended; but some caution is necessary in making this mixture of
a proper strength, for if too strong, it is injurious to plants; and
the experiment does not seem, as yet, to have been conducted with
sufficient care to insure safety and success. Dusting lime over the
plants when wet with dew has been tried, and found of some use; but
this and all other remedies will probably yield in efficacy to Mr.
Haggerston's mixture of whale-oil soap and water, in the proportion
of two pounds of the soap to fifteen gallons of water. Particular
directions, drawn up by Mr. Haggerston himself, for the preparation
and use of this simple and cheap application, may be found in the
"Boston Courier" for the 25th of June, 1841, and also in most of
our agricultural and horticultural journals of the same time. The
utility of this mixture has already been repeatedly mentioned in this
treatise, and it may be applied in other eases with advantage. Mr.
Haggerston finds that it effectually destroys many kinds of insects;
and he particularly mentions plant-lice of various kinds, red spiders,
canker-worms, and a little jumping insect which has lately been found
quite as hurtful to rose-bushes as the slugs or young of the saw-fly."
Rose-Bug.--_Macrodactylus subspinosa._--"Common as this insect is
in the vicinity of Boston, it is, or was a few years ago, unknown in
the northern and western parts of Massachusetts, in New Hampshire,
and in Maine. It may, therefore, be well to give a brief description
of it. This beetle measures seven-twentieths of an inch in length.
Its body is slender, tapers before and behind, and is entirely
covered with very short and close ashen-yellow down; the thorax is
long and narrow, angularly widened in the middle of each side, which
suggested the name _subspinosa_, or somewhat spined; the legs are
slender, and of a pale red color; the joints of the feet are tipped
with black, and are very long, which caused Latreille to call the
genus _Macrodactylus_, that is, long toe, or long foot. The natural
history of the rose-chafer, one of the greatest scourges with which
our gardens and nurseries have been afflicted, was for a long time
involved in mystery, but is at last fully cleared up. The prevalence
of this insect on the rose, and its annual appearance, coinciding with
the blossoming of that flower, have gained for it the popular name by
which it is here known. For some time after they were first noticed,
rose-bugs appeared to be confined to their favorite, the blossoms of
the rose; but within thirty years, they have prodigiously increased
in number, have attacked at random various kinds of plants in swarms,
and have become notorious for their extensive and deplorable ravages.
The grape-vine in particular, the cherry, plum, and apple-trees, have
annually suffered by their depredations; many other fruit-trees and
shrubs, garden vegetables and corn, and even the trees of the forest,
and the grass of the fields, have been laid under contribution by
these indiscriminate feeders, by whom leaves, flowers, and fruits are
alike consumed. The unexpected arrival of these insects in swarms, at
their first coming, and their sudden disappearance at the close of
their career, are remarkable facts in their history. They come forth
from the ground during the second week in June, or about the time of
the blossoming of the Damask Rose, and remain from thirty to forty
days. At the end of this period the males become exhausted, fall to
the ground, and perish, while the females enter the earth, lay their
eggs, return to the surface, and, after lingering a few days, die
also. The eggs laid by each female are about thirty in number, and are
deposited from one to four inches beneath the surface of the soil;
they are nearly globular, whitish, and about one-thirtieth of an inch
in diameter, and are hatched twenty days after they are laid. The
young larvæ begin to feed on such tender roots as are within their
reach. Like other grubs of the Scarabæus, when not eating, they lie
upon the side, with the body curved, so that the head and tail are
nearly in contact; they move with difficulty on a level surface, and
are continually falling over on one side or the other.
"They attain their full size in autumn, being then nearly
three-quarters of an inch long, and about an eighth of an inch in
diameter. They are of a yellowish white color, with a tinge of blue
towards the hinder extremity, which is thick and obtuse, or rounded;
a few short hairs are scattered on the surface of the body; there
are six short legs, namely, a pair to each of the first three rings
behind the head, and the latter is covered with a horny shell of a
pale rust color. In October they descend below the reach of frost,
and pass the winter in a torpid state. In the spring they approach
toward the surface, and each one forms for itself a little cell, of
an oval shape, by turning round a great many times, so as to compress
the earth, and render the inside of the cavity hard and smooth.
Within this cell the grub is transformed to a pupa, during the month
of May, by casting off its skin, which is pushed downward in folds
from the head to the tail. The pupa has somewhat the form of the
perfected beetle, but it is of a yellowish white color, and its short,
stump-like wings, its antennæ, and its legs, are folded upon the
breast, and its whole body is inclosed in a thin film that wraps each
part separately. During the month of June this filmy skin is rent, the
included beetle withdraws from its body and its limbs, bursts open its
earthen cell, and digs its way to the surface of the ground. Thus the
various changes from the egg to the full development of the perfected
beetle are completed within the space of one year.
"Such being the metamorphoses and habits of these insects, it is
evident that we cannot attack them in the egg, the grub, or the pupa
state; the enemy, in these stages, is beyond our reach, and is subject
to the control only of the natural but unknown means appointed by the
Author of Nature to keep the insect tribes in check. When they have
issued from their subterranean retreats, and have congregated upon
our vines, trees, and other vegetable productions in the complete
enjoyment of their propensities, we must unite our efforts to seize
and crush the invaders. They must indeed be crushed, scalded, or
burned, to deprive them of life, for they are not affected by any
of the applications usually found destructive to other insects.
Experience has proved the utility of gathering them by hand, or of
shaking them, or brushing them from the plants into tin vessels
containing a little water. They should be collected daily during the
period of their visitation, and should be committed to the flames,
or killed by scalding water. The late John Lowell, Esq., states,
that in 1823, he discovered on a solitary apple-tree the rose-bugs
'in vast numbers, such as could not be described, and would not be
believed if they were described, or at least none but an ocular
witness could conceive of their numbers. Destruction by hand was
out of the question' in this case. He put sheets under the tree,
and shook them down and burned them. Dr. Green, of Mansfield, whose
investigations have thrown much light on the history of this insect,
proposes protecting plants with millinet, and says that in this way
only did he succeed in securing his grape-vines from depredation. His
remarks also show the utility of gathering them. 'Eighty-six of these
spoilers,' says he, 'were known to infest a single rose-bud, and were
crushed with one grasp of the hand.' Suppose, as was probably the
case, that one-half of them were females; by this destruction, eight
hundred eggs, at least, were prevented from becoming matured. During
the time of their prevalence, rose-bugs are sometimes found in immense
numbers on the flowers of the common white-weed, or ox-eye daisy,
(_Chrysanthemum leucanthemum_,) a worthless plant, which has come to
us from Europe, and has been suffered to overrun our pastures, and
encroach on our mowing lands. In certain cases it may become expedient
rapidly to mow down the infested white-weed in dry pastures, and
consume it with the sluggish rose-bugs on the spot.
"Our insect-eating birds undoubtedly devour many of these insects, and
deserve to be cherished and protected for their services. Rose-bugs
are also eaten greedily by domesticated fowls; and when they become
exhausted and fall to the ground, or when they are about to lay their
eggs, they are destroyed by moles, insects, and other animals, which
lie in wait to seize them. Dr. Green informs us that a species of
dragon-fly, or devil's needle, devours them. He also says that an
insect, which he calls the enemy of the cut-worm, probably the larva
of a Carabus, or predaceous ground-beetle, preys on the grubs of
the common dor-bug. In France, the golden ground-beetle (_Carabus
auratus_) devours the female dor or chafer at the moment when she is
about to deposit her eggs. I have taken one specimen of this fine
ground-beetle in Massachusetts, and we have several other kinds
equally predaceous, which probably contribute to check the increase of
our native Melolonthians."--_Harris._
A. J. Downing recommends the use of open-mouthed bottles, half
filled (and occasionally renewed) with a mixture of sweetened water
and vinegar, and placed about the plant. He also recommends pouring
boiling water on the ground, under the bushes, at the first appearance
of the insects, and before their wings are formed. They nearly all
rise to the surface of the ground, and emerge about the same time
that the Damask Rose first begins to open. A little observation
will enable the cultivator to seize the right time for the scalding
operation.
Rose Leaf-Hopper.--_Tettigonia Rosæ_ of Harris, who states that it
has been mistaken for the Vine-fretter, or Thrips. It is yellowish
white, and about three-twentieths of an inch long; the male has two
recurved appendages at the tip of its hind body. Dr. Harris says,
"Swarms of these insects may be found in various stages of growth
on the leaves of the rose-bush through the greater part of summer,
and even in winter upon housed plants. Their numerous cast skins may
be seen adhering to the lower side of the leaves. They pair and lay
their eggs about the middle of June, and they probably live through
the winter in the perfect state, concealed under fallen leaves and
rubbish on the surface of the ground. Fumigation with tobacco, and the
application of a solution of whale-oil soap in water with a syringe,
is the best means for destroying these leaf-hoppers."
We have enumerated but a very small part of the numerous insects which
infest the rose, and in the absence of correct information on this
important branch of floriculture, it is much to be hoped that farther
investigations will be made by men of leisure. As an instance of the
great variety of these insects, a French writer remarks that he "found
in less than an hour, on the leaves of two species only of the Rose,
six kinds of small caterpillars, all differing from each other in
the number of their feet, the color of their head and body, and the
lines and points with which they were marked. Their habits were all
apparently the same. They lived between two or three folds which they
had secured in shape by the films of their silk. Thus enveloped and
protected, they eat the leaf until it is wholly or at least partly
consumed. They then endeavor to establish themselves on another leaf,
in which also they enwrap themselves, and consume it in the same
manner. The plants attacked by these caterpillars are known by their
ruffled leaves, partly eaten, and more or less covered with silk." The
writer does not give their name, nor the result of any experiments for
their destruction; he merely mentions it as an instance of the great
abundance of insects on almost every plant. Such being the case, there
is abundant room for farther observation and research.
HISTORY OF THE ROSE.
"Round every flower there gleams a glory,
Bequeathed by antique song or story;
To each old legends give a name,
And its peculiar charm proclaim.
O'er smiling lawn, through shady grove,
Our dreaming poets pensive rove,
And strive to read their language rare,
And learn the lesson latent there."