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CHAPTER IX. DISEASES AND INSECTS ATTACKING THE ROSE.

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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 larv? 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 ros?. 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 sph?rotheca 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.[pg 141] 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 larv? 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 ros?.—this very common insect is a scourge to roses, from the facility of its[pg 142] 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 larv? 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 larv?. the bédéguars, formed by the puncture of the cynips ros?, were formerly employed in medicine as astringents. harris enumerates the american species as follows:

cynips bicolor.—“round, prickly galls, of a reddish[pg 143] 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 antenn?, is of a brownish-red or cinnamon color, with four little longitudinal grooves on the top of the thorax, the lower part of the antenn? 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 ros?, 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 ros?, 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 pygm?a, but has not the red thorax of these three closely allied species. it is of a deep and shining black color. the first two[pg 144] 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[pg 145] 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[pg 146] 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[pg 147] 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[pg 148] globular, whitish, and about one-thirtieth of an inch in diameter, and are hatched twenty days after they are laid. the young larv? begin to feed on such tender roots as are within their reach. like other grubs of the scarab?us, 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 antenn?, 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.

[pg 149]

“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.[pg 150] 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[pg 151] to open. a little observation will enable the cultivator to seize the right time for the scalding operation.

rose leaf-hopper.—tettigonia ros? 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[pg 152] 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.”

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