« AnteriorContinuar »
appears in large bunches; branch after branch becomes infected; the tree grows cankery, pines, and dies. How this is effected, no one knows, though the cause and effect are too evident to escape the notice of the commonest clown. In large orchards, it is vain to hope for a cure; but not so in gardens. Directly you see the least morsel of cotton, make up your mind to a little trouble, and you will get rid of it. In the first place, get a plasterer's white-washing brush; then get 2 large pot of double size; make your man heat it, till it is quite liquid; then go with him into the garden, and see that he paints over every patch of white, though not bigger than a sixpence; the next morning have the size-pot heated again, and have another hunt; and keep on doing so every morning for a fortnight. Your man will tell you it's no use—tell him that's your business, not his. Your neighbours will laugh at you for your pains—do it before they are up. I have tried it, and know it to be effectual. Spirit of tar has been used with partial effect; so also has resin. White-washing has been often tried, and, as it contains some size, is not entirely useless; and some horticulturists think it ornamental-I do not."'*
The apple-tree, as well as the quince, mountain ash, June berry, and various species of thorns and aronias are attacked by the larvæ of the two-striped sa perda, (Saperda bivittata, Say,) denoted by the adjoining figure. The upper side of the body of the perfect insect is marked with two longitudinal white stripes between three others of a light-brown colour, while the face, the antennæ, the under side of the body, and the legs, are white. This beetle varies in length from a little more than one half to three fourths of an inch. It comes forth from the trunks of the trees early in June, making its escape in the night, during which time only it uses its ample wings in passing from one tree to another in search of companions and for food. In the day-time, it keeps at rest among the leaves of the plants on which it feeds. In the months of June and July, the females deposite their eggs upon the bark of the trees, near the roots, and the larvæ or borers hatched from them consist of fleshy whitish grubs, without legs, nearly cylindrical in their form, and tapering a little from the first ring to the end of the body. The head is small, horny, and of a brownish colour. The first ring is much larger than the others, the next two very short, and, like the first, are covered with punctures and very minute hairs. This grub, with its strong jaws, cuts a cylindrical passage through the bark, and pushes its castings backwards out of the hole, while it bores upwards into the wood. It continues in the larva state two or three years, during which it penetrates eight or ten inches into the trunk of the tree, its burrow at the end approaching to, and being covered only by, the bark. It is in this situation that its transformation takes place, which is completed about the first of June, when the beetle gnaws through the bark that covers the end of the burrow, and comes out of its place of confinement in the night. One of the oldest, safest, and most successful modes of destroying this borer is, to thrust a wire into the hole it has made; or, what would probably answer as well, to plug it up with soft wood.t.
Young apple-trees, and the extremities of the limbs of older trees, are very much subject to the attacks of a small species of bark-louse, (Coccus * * * * *?) The limbs and smooth parts of the trunks are sometimes completely covered with these insects. They measure about one tenth of an inch in length, are of an oblong-oval shape, gradually decreasing to a point at one end, and are of a brownish colour, very near to that of the bark of the tree. There is also another species of coccus, which inhabits the apple-tree, differing from the one above men
* See London Gardener's Magazine, ix., p. 335. + See Harris' Report, p. 89.
tioned in several important particulars. It is one of the kind in which the body of the female is not large enough to cover her eggs, for the protection whereof, provision is made, consisting, in this species, of a kind of membraneous shell, of the colour and consistence almost of paper. In autumn, and during winter, these insects are seen in a torpid state, and of two different forms and sizes, on the bark of the trees. The larger ones measure less than a tenth of an inch in length, and are in the shape of a common oyster-shell, being broad at the hinder extremity, but tapering towards the other, which is surmounted by a little oval, brownish scale. "The small ones, which are not much more than half the length of the others, are of an oblong-oval shape, or almost four-sided, with the ends rounded, and one extremity is covered by a dark-coloured, minute, oval scale. For a description of the general habits of this family of insects, the reader is referred to our article on the orange-tree, under the head of “ Insects."'*
The tender buds and young leaves of the apple-tree are sometimes attacked, in May and June, by multitudes of small caterpillars, described by Dr. Harris, under the name of the eye-spotted penthina (Penthina oculana.) They are of a pale and dull-brown colour, warty and slightly downy, with the head and the top of the first ring of a dark shining brown. They usually acquire their growth by the middle of June, at which time they transform, and come out in the winged state early in July. These caterpillars live singly in the buds or opening foliage, which they fasten together and devour. The only sure mode recommended to destroy them is, to crush the withered clusters of leaves containing them or their chrysalides, and thus “nip them in the bud." But one of the greatest pests to the American orchards, as well as to the foliage of the elm, and sometimes of the cherry, plum, linden, and other trees, is the canker-worm, first described by Professor Peck under the name of Phalana vernata. According to Dr. Harris, the canker-worm moths begin to make their appearance after the first hard frost in the autumn, usually towards the end of October, and they continue to come forth, in greater or smaller numbers, according to the mildness or severity of the weather after the frosts have begun. Their general time of rising, however, is in the spring, beginning about the middle of March, but sometimes before, and at others, after this time; and they continue to come forth for the space of about three weeks. It has been observed that there are more females than males among those that appear in the autumn and winter, and that the males are the most abundant in the spring. The sluggish and wingless females instinctively make their way towards the nearest trees, and creep slowly up their trunks. In a few days afterwards they are followed by the winged and active males, which flutter about and accompany them in their ascent, during which, the two sexes pair. Soon after this, the females lay their eggs upon the branches of the trees, placing them on their ends, close together in rows, forming clusters of sixty to one hundred eggs or more, which is the number usually laid by each. The eggs are glued to each other, and to the bark, by a grayish varnish, which is impervious to water; and the clusters are thus securely fastened in the forks of the small branches, or close to the young twigs and buds. The eggs are usually hatched between the first and the middle of May, or about the time that the red currant is in blossom, and the young leaves of the apple-tree begin to expand. The little canker-worms, upon making their escape from the eggs, gather upon the tender leaves, and, on the occurrence of cold and wet weather, seek shelter in the bosom of a bud, or into the flowers, when the latter appear. The leaves, when first attacked, will be found pierced with small holes, which become larger and more irregular as the worms increase in size, until nearly all the pulpy parts are consumed. A very great difference of colour is observable among these
* See also Harris' Report, pp. 201 et 203.
worins of different ages, and even among those of the same age and size. When very young, they have two minute warts on the top of the last rings, and they are then generally of a blackish or dusky-brown colour, with a yellowish stripe on each side of the body; there are two whitish bands across the head; and the belly is whitish. When fully grown, these individuals become ash-coloured on the back, and black on the sides, below which, the pale, yellowish line remains. Some are found of a dull greenish-yellow, and others of a clay-colour, with slender interrupted blackish lines on the sides, and small spots of the same colour on the back. The head and feet partake of the general colour of the body; the belly is paler. When not eating, they remain stretched out at full length, and resting on their fore and hind legs, beneath the leaves. When fully grown and well fed, they measure nearly or quite an inch in length. They cease feeding when about four weeks old, at which time they begin to quit the trees. Some creep down by the trunks, but great numbers let themselves down by their slender threads from the branches, their instincts prompting them to get to the ground by the easiest and most direct course possible. After reaching the ground, they immediately burrow into the earth, to the depth of two to six inches, unless prevented by weakness, or by the hardness of the soil. In the latter case, they die, or undergo their transformations on the surface. In the former, they make little cavities or cells in the ground, by turning round repeatedly, and fastening the loose grains of earth about them with a few silken threads; and, within twentyfour hours afterwards, they are changed into chrysalides, and in due time, emerge from these retreats in their perfect form. In order to protect the trees from the ravages of the canker-worm, the only thing that would seem necessary would be to prevent the wingless females from ascending the trunks to deposit their eggs. The expedients usually resorted to for this purpose, are, to fit a close collar of lead, tin, wood, or other materials, around the trunks of the trees, or a circular trough filled with oil. The application of belts of tar, liquid Indian rubber, and other viscid substances, to the bodies of the trees have been employed with partial success.
The apple-tree is also infested by the larvæ of the white-marked orgia, or tussock-moth (Orgia leucostigma, Harris.) These small, slender caterpillars are of a bright-yellow colour, and are sparingly clothed with long and fine yellow hairs on the sides of their bodies. The females, in the adult state, though seemingly wingless, have two little scales or stinted wings, while the males have large ashen-gray wings, the upper pair of which are crossed by dark wavy bands, with a small black spot near the tip, and a minute white crescent near the outer hind angle. The body of the male is small and slender, with a row of little tufts along the back, and the wings expand one inch and three eighths. The females are of a lighter gray than the males, and their bodies are much thicker, and are of an oblong-oval shape. Different broods of these insects appear at various times in the course of the summer, but the greater number come to maturity and lay their eggs in the latter part of August and the beginning of September, which are not hatched before the following spring. It is stated by the late Mr. B. H. Ives, of Salem, Massachusetts, in vol. i., p. 52, of Hovey's “Gardener's Magazine,” that on passing through an apple orchard in February, he “ perceived nearly all the trees speckled with occasional dead leaves, adhering so firmly to the branches as to require considerable force to dislodge them. Each leaf covered a small patch of from one to two hundred eggs, united together, as well as the leaf, by a gummy and silken fibre, peculiar to the moth.” In the March following, he visited the same orchard, and as an experiment, cleared three trees, from which he took twenty-one bunches of eggs. The remainder of the trees he left untouched until the 10th of May, when he found the caterpillars were hatched from the egg, and had commenced their slow, but sure work of destruction. He watched them from time to time, until many branches had been spoiled of their leaves, and in the autumn were entirely destitute of fruit; while the three trees, which had been cleared of the eggs, were flush with foliage, each limb, without exception, ripening its fruit. In addition to a brief notice of the American lackey caterpillar, (Clisiocampa americana,) in our article on the Virginian cherry-trees, under the head of "Insects,” it may be proper here to state, that, where proper attention has not been paid to prevent its ravages, it prevails to such an extent as almost entirely to strip the apple orchards, as well as the cherry-tree of their foliage. This insect, from its abundance in all parts of the country, and being known almost exclusively in common language, by the name of the caterpillar, requires no further description. Various methods have been recommended to destroy this insect, such as burning and crushing the nests, early in the morning or evening while the vermin are at their repose, and the collection and destruction of their eggs in the winter or early part of spring. If a liberal bounty for the collection of the eggs were to be offered, as was suggested by the late Judge Lowell, and continued for the space of ten years, this destructive caterpillar would be nearly exterminated at the end of that time. Another insect, which may be called the tent-caterpillar of the forest, (Clisiocampa sylvatica, Harris,) very much resembling the preceding in its habits, preys upon the leaves of the oak, the hickory, and more rarely upon those of the apple-tree. Two other species of gregarious caterpillars, Notodonta concinna, and Pygera ministra, of Harris, also swarm on the apple, cherry and plum-trees, towards the end of summer, stripping whole branches of their leaves. The caterpillar of the American lappet-moth, (Gastropacha americana, Harris,) appears in September, and makes the leaves of the apple its food, which it only eats in the night. A large green caterpillar, (Attacus cecropia, Harris,) also makes its appearance on the apple-tree in the months of July and August, as well as upon the currant, the berberry, the cherry, and the plum.*
Among the insects which create the greatest havock in orchards, in Europe, are the larvæ of the Tinea padella, of Linnæus, which congregate in such vast numbers, that the leaves vanish before them, and by mid-summer, the trees are often completely defoliated by them.
Apples often fall off prematurely, both in Europe and in America, from being worm-eaten. The cause of this is a beautiful little insect, called the apple-worm moth, Tinea pomonella, of Linnæus; Pyralis pomana, of Fabricius; and Carpocapsa pomonella, of modern entomologists. The habits and economy of this moth have been satisfactorily pointed out by a writer in the London “Entomological Magazine,” and a good account of it is also given by Dr. Harris, in his “Report on the Insects of Massachusetts injurious to Vegetation," p. 353. The larvæ of this insect leave their chrysalides from the middle of June to the first of July, or at the time the young apples become well set. The moth now lays her eggs in the eye of the apple, one only in each, by introducing its long ovipositor between the leaves of the calyx, which form a tent above it, that effectually shields it from the inclemency of the weather, or other casualties. “As soon as the egg hatches,” says the writer above referred to," the little grub gnaws a hole in the crown of the apple, and soon buries itself in its substance; and it is worthy of remark, that the rind of the apple, as if to afford every facility to the destroyer, is thinner here than in any other part, and, consequently, more easily pierced. ***** The grub, controlled by an unvarying instinct, eats into the apple obliquely downwards, and, by thus avoiding the core and pips, in no way hinders its growth. At first, it makes but slow progress, being little bigger than a thread; but, after a fortnight, its size and its operations have much increased. It has now eaten half-way down the apple; and the position of the hole at the top, if the apple continue upright, or nearly so,
* See Harris' Report, pp. 261, 269, 273, 279, 307, 312, 332, et 348.
is convenient for a purpose it has up to this time been used for, that is, as a pass to get rid of its little pellets of excrement, which are something like fine sawdust, or coarse sand. Another communication with the outer air is therefore required; and it must be so constructed as to allow the power of gravity to assist in keeping it clear. It is accordingly made directly downwards, towards that part of the apple which is lowest ; and thus the trouble of thrusting the pellets upwards through the eye of the apple is saved, and a constant admission given to a supply of air without any labour. The hole now made, is not, however, sufficiently open for an observer to gain by its means any knowledge of what is going on within; this is only to be obtained by cutting open a number of the apples, as they gradually advance towards ripeness; the hole is, however, very easily seen, from its always having adhering to it, on the outside, an accumulation of the little grains which have been thrust through. Having completed this work, the grub returns towards the centre of the apple, where he feeds at his ease. When within a few days of being full fed, he, for the first time, enters the core, through a round hole gnawed in the hard horny substance which always separates the pips from the pulp of the fruit; and the destroyer now finds himself in that spacious chamber, which codlings, in particular, always have in their centre. From this time, he eats only the pips, never again tasting the more common pulp, which hitherto had satisfied his unsophisticated palate; now nothing less than the highly-flavoured aromatic kernels will suit his tooth; and on these, for a few days, he feasts in luxury. Somehow or other, the pips of an apple are connected with its growth, as the heart of an animal with its life. Injure the heart, an animal dies—injure the pips, an apple falls. Whether the fall of his house gives the tenant warning to quit, I cannot say, but quit he does, and that almost immediately. He leaves the core, crawls along his breathing and clearing-out gallery, the mouth of which, before nearly closed, he now gnaws into a smooth round hole, which will permit him free passage, without hurting his fat, soft, round body; then out he comes, and, for the first time in his life finds himself in the open air. He now wanders about on the ground till he finds the stem of a tree; up this he climbs, and hides himself in some nice little crack in the bark. I should remark that the fall of the apple, the exit of the grub, and his wandering to this place of security, usually take place in the night-time. In this situation he remains without stirring for a day or two, as if to rest himself after the uncommon fatigue of a two yards' march; he then gnaws away the bark a little, in order to get further in out of the way of observation; and, having made a smooth chamber, big enough for his wants, he spins a beautiful little milkwhite silken case, in which, after a few weeks, he becomes a chrysalis, and in this state remains throughout the winter, and until the following June, unless some unlucky black-headed tit, running up the trunk, peeping into every cranny, and whistling out his merry see-saw, happens to spy him; in which case, he is plucked without ceremony from his retreat, and his last moments are spent in the bird's crop. But, supposing no such ill-fortune betide him, by the middle of June he is again on the wing, and hovering round the young apples on a midsummer evening as before. By burning weeds in your garden, at this time of the year, you will effectually drive away this little moth. If you have trees, the crops of which you value, make a smoking fire under each. It will put you to some inconvenience if your garden be near your house; but the apples will repay you for that." As the apple-worm instinctively leaves the fruit soon after it falls from the trees, it has been recommended to gather up all wind-fallen fruit daily, and give it to cattle or swine, in order to kill these insects, before they have time to escape. . Mr. Joseph Burrelle, of Quincy, Massachusetts, in vol. xviii. of the “New England Farmer," says that, “if any old cloth is wound around or hung in the crotches of the trees, the apple-worms will conceal themselves therein