American Pomology Part 17

=ORTHOPTERA.=--GRa.s.sHOPPERS.

The insects of this order have an imperfect transformation. The eggs hatch at once into young insects, that resemble their parents in form and habits, excepting that they do not get their wings till they approach the adult state. The young consume food voraciously, and the perfect insects are not only still more hungry, but, having increased powers of locomotion, they are more widely destructive. These are the true _Locusts_, and though chiefly injurious to the farm and garden, infesting the meadows and corn-fields, the gra.s.shoppers, when winged, often attack the foliage of our young orchard trees toward the end of summer. But when we contemplate the invasion of the great western plague, belonging to this order, which rivals that terrible scourge, the Locust of the eastern continent, in numbers and voracity, we may well dread their increase and appearance in other parts of the country. The gra.s.shoppers that have invaded Kansas and other Western States are, like all the rest of this group of _Orthoptera_, true Locusts.

This order is called _Orthoptera_, from their straight wings; it embraces several groups, c.o.c.kroaches, crickets, gra.s.shoppers, or locusts, etc., which are all injurious, except the _Mantis_, which is predacious, and therefore useful.

=HEMIPTERA.=--BUGS AND HARVEST-FLIES.

This order contains many insects that are injurious to the nurseryman, to the orchardist, and to the gardener. They are characterized by having a proboscis instead of a mouth with jaws; they can suck, but they cannot bite. The proboscis is often h.o.r.n.y, and armed with two pair of bristles, when it becomes a more formidable weapon for attack.

Bugs have four wings; they do not pa.s.s through the usual metamorphoses of insect life; but are born with legs and feeding apparatus like the perfect insects, except that some have no wings. Bugs are all injurious to man, excepting such as are predacious, which are serviceable by destroying other insects. Many are very small; and yet their countless numbers and wonderful fecundity enable them to do immense damage, as is true of the _Aphides_ and _Coccidae_, the _Tingis_, the _Tettigonia vitis_, called the Thrips by our vine-dressers; and still more so of the Chinch-bug of the Western prairies, which destroys whole crops of our most important cereals.

The colored juice of some bugs is used in the arts. The coccus of the p.r.i.c.kly pear, in Central America, is gathered and dried to form the cochineal of the shops.

Hemipterous insects are divided into two groups. True bugs, called _Hemiptera heteroptera_, having the wing-covers opaque at the base, and laid horizontally, and crossing each other obliquely at the end, overlapping; and the Harvest-flies, such as Plant-lice and Bark-lice.

These, the _Hemiptera h.o.m.optera_, have the wing-covers of one texture throughout, not horizontal, but more or less sloping, and not crossing one another behind. Among these, which all feed upon plants, some very troublesome pests will here be noticed.

=COCCIDIANS.=--BARK-LICE.

=Aspidiotus conchiformis=, or the Apple Bark-louse, is very numerous in many parts of our country, particularly north of lat.i.tude 40 degrees. It commits sad devastations in some sections. Individually, it is but a little scale; but these animals are wonderfully prolific and soon cover every twig of the tree, obstructing its transpirations, and abstracting its vital juices; the leaves, and even the fruit are overrun with these miserable scales, but the twigs are their favorite resort. These scales are oblong, shaped like an oyster sh.e.l.l; flat and brown, often crowding upon one another. In the winter and spring, they contain or cover a number of small, round, white eggs, which hatch out in the spring, in May, attach themselves to the bark, and absorb the juices: various remedies have been suggested, and more or less thoroughly tested. The restoration of the thrifty growth of the tree is considered essential to success; and without this, all remedies are looked upon as unavailing. Some orchardists think that thorough drainage and cultivation of the land would alone banish the lice, but this can hardly be hoped. Strong lye, or solutions of potash, or soda, white-wash, and sulphur, have been used, and tobacco boiled in lye, soft-soap and tar mixed with linseed oil, which makes a kind of varnish. Mr. Walsh tells us that applications, to destroy this insect, are better made in May or June, as the eggs are protected by the scale in winter, and it is impermeable to watery solutions. This pest has been imported from Europe. Walsh recommends the use of Lady-birds to check the Bark-lice.[25]

=Lecanium pyri=, (_Fitch_), or the Pear Bark-louse, is a hemispherical brown scale, as large as a split pea. They may be found in summer on the under side of the limbs, and are the remains of dead females, which cover the eggs and young brood. This insect would be very injurious, were it to increase in numbers considerably. Let young trees be examined in June, when the scales may easily be found, removed, and destroyed.

=Lecanium persici=, or the Peach Bark-louse, is described, by Fitch, as similar in size to the above, found on smooth bark near a bud; it is blackish, uneven, shining, with a pale margin.

Another pear tree bark-louse was described by the lamented A.O. Moore, of New York, as a white, papery scale, giving a claret-colored juice when sc.r.a.ped. This, in the winter, consists of a defunct mother and her brood of eggs, the breaking of which gives the color. Alkaline washes are recommended to be applied in the spring. Mr. Walsh thinks this insect cannot be the same as that mentioned by Dr. Harris, on p.

222 of his report, under the name of _Coccus cryptogamus_, (_Dalman_), who found it upon the Aspen, and therefore he has named it _Coccus?

Harrisii_.[26]

=Lecanium vitis=, (_Linn._), or the Vine Bark-louse, is mentioned by Fitch as having been found on grape vines in June. It is hemispherical and brown. A cottony substance was extruded from one end of the scale, and this increased until July, when minute insects crept out and scattered over the bark, upon which they fixed themselves. This insect is not very common, but its first appearance should be closely watched, and its destruction promptly effected.

=APHIDES.=--PLANT-LICE.

These are the most extraordinary insects, being found upon almost all parts of plants, and there is scarcely a species which does not support one or more kinds peculiar to itself. Then they are so exceedingly prolific! Reaumur proved that one individual, in five generations, may become the progenitor of nearly six thousand millions of descendants. Most of these insects, which we find so abundant upon our trees, are wingless females. Winged insects, both male and female, appear later in the season, and after laying their eggs, they soon perish. Some lay in the fall, others wait till spring. When these eggs hatch, the brood consists wholly of females, which are wingless, and do not lay eggs, but are viviparous and produce from fifteen to twenty young lice in the course of a day. This second generation are also wingless, and at maturity produce their young, and so on to the seventh generation, without the approach of a single male, until the autumn, when a brood of males and females appears, which are both winged at maturity, and then the eggs are laid for the next year's brood, and the parents die.[27]

The injuries occasioned by plant-lice, are much greater than would at first be expected, from an observation of the small size and extreme weakness of the insects; but these make up by their numbers what they lack in strength individually, and thus become formidable enemies to vegetation. By their punctures and the quant.i.ty of sap they draw from the leaves, the functions of these important organs are deranged, or interrupted, the sap is withdrawn or contaminated, and unfitted to supply the wants of vegetation. Plants are differently affected; some wither and cease to grow, their leaves and stems become sickly, and die from exhaustion. Others, not killed, are greatly impeded in their growth; the tender parts, which are attacked, become stunted and curled. The punctures of the lice appear to poison some plants, producing warts or swellings, which are sometimes solid, sometimes hollow, containing within them a swarm of lice, descendants of a single individual.[28] These last are often seen upon the leaves of the Elm, and upon some Poplars, and other trees; but I have not found any upon the foliage of our cultivated fruits, unless it be those on the grape.

=Aphis mali=, or the Apple Leaf-louse, is a small, green insect without wings, accompanied by a few black and green ones having wings.

These are all crowded together upon the green tips of twigs, and under the leaves, sucking the sap. The eggs remain in deep cracks of the bark during the winter, and hatch as soon as the buds expand in the spring. The most successful treatment is to sc.r.a.pe off the loose bark, and to apply to the stems of the trees alkaline or lime washes. Many of our familiar little winter birds consume these eggs. In the spring and summer, alkaline solutions may be used with advantage, syringed or sprinkled upon the affected shoots and foliage.

The smell of these insects is peculiar, which, indeed, is generally characteristic with bugs. Each sort seems to derive a special flavor from the tree or plant upon which it feeds. Most insects of this family secrete copiously a sweetish fluid, called the honey dew, which is ejected from two little horns or nectaries, that project, one on each side of their bodies. This sweet material attracts a great many flies, and other insects, particularly ants, which are the constant attendants of these creatures, and are said to protect them from their enemies in order to obtain their sweet secretion. Some entomologists have called _Aphides_ the Ants' cows.

No one, who is acquainted with the _Aphides_, and the various insects which prey upon them, will ever permit a valuable plant to suffer injury from these pests. He will collect some of the _Aphis'_ enemies alive, carry them to the affected plant, and set them free to do their work; there they will remain while the food lasts. The _Aphides_ have more numerous, more active, and more inveterate enemies than insects of any other group--these are the means by which their wonderful fecundity is kept in check. Among them are the Aphis-lions, which are the larvae of the Golden-eyed and Lace-wing flies, belonging to the order _Neuroptera_. They are reddish-brown, with a dark stripe down the middle, and a cream-colored one on each side; bodies long, narrow, and wrinkled transversely. Their jaws are long, curved like sickles, projecting forward from their heads horizontally.[29]

The _Coccinellidae_, mentioned as useful members of the order _Coleoptera_, on a previous page, are among the most active enemies of the _Aphides_. The eggs are laid in cl.u.s.ters of twenty to forty on the under side of a leaf, to which they are closely glued; they are oval, and light yellow. They hatch into small blackish larvae, which are active, and which boldly attack an _Aphis_ much larger than themselves, leaving only the empty skin. They consume hundreds while in the larval state, about two weeks, when they attach themselves by the tail, and go into the pupa state. One of the largest of these Lady-birds is the _Mysia 15-punctata_; the larva is a clear white, the middle of the back tinged with red, and two or three black spots on each segment--nearly a hundred species of Lady-birds are found in this country. The perfect insect, as well as the larvae, feed upon _Aphides_, and instead of being destroyed, they should be cherished and encouraged.

Besides these, there are other inveterate enemies of the plant-lice in the _Syrphidae_, which are two-winged flies, resembling the common house-fly, but handsomer. They deposit their eggs where _Aphides_ exist; the maggot, which hatches from these, seizes upon the first _Aphis_ that comes within his reach, and sucks its fluids. A medium-sized worm will consume a hundred lice in an hour. They are always found in a colony of _Aphides_.[30]

=Aphis prunifoliae=, or the Plum Leaf-louse, is black, with pale green abdomen. It is found on the under side of the leaves, which become wrinkled and distorted. It is not so abundant as some other species, but its habits are similar.[31]

=Aphis cerasi=, (_Fabric._), or the Cherry Plant-louse, is very common, very numerous, and very black. They appear with the first expansion of the leaves, and continue or are renewed when destroyed, and remain until mid-summer, when they generally disappear. Their numbers are almost incredible, and they give a young cherry tree a wretched appearance. On the under surface of a small leaf, three-fourths of an inch long, Mr. Fitch counted one hundred and ninety lice, on one side only of the midrib. Their natural enemies come to the rescue to check their wonderful increase, and sometimes will utterly rout the _Aphides_ in a single week.[32]

The remedies advised for the apple tree _Aphides_, are equally applicable to those of the cherry, and their natural enemies are the same and equally efficacious; but _Aphides_ have internal foes likewise, that may be named here. The Ichneumon-flies are parasitic, their larvae feed upon the substance of the _Aphides_. The genus _Aphidius_ is particularly provided to furnish parasites to these insects, in which they deposit a single egg selecting a louse of the proper size to sustain their progeny: the egg hatches to a larva, which exhausts the _Aphis_ by the time it has attained its growth, when the poor creature fastens itself securely to the leaf, and dies, leaving its carcase a secure resting place for the pupa of the Ichneumon. These parasitic-insects, which feed internally upon the _Aphides_, are as effective in their destruction as the Aphis-lions, or any other cla.s.s of their enemies.[33]

=Aphis persicae=, or the Peach Tree-louse, punctures the leaves of this plant, and Dr. Fitch[34] thinks, is the common though not the only cause of the curl in the peach tree leaves. Our intelligent orchardists have found these insects occasionally in the curled leaves of the peach, but do not agree with this distinguished entomologist, in considering them a cause of that malady.

=Aphis vitis?=, or the Vine _Aphis_, is often quite troublesome on vigorous young shoots of the grape vine, both wild and cultivated, particularly the former. These insects soon cripple the growth of the shoot. The species is not known to be different from that of Europe.

This insect is briefly mentioned by T. Glover, in Patent Office Rept.

for 1854, p. 79. Dr. Fitch describes as a grape leaf-louse, the _Pemphigus vitifolia_, which inhabits the gall-like excrescences upon the foliage of some varieties, particularly those with thin leaves.

=Aphis ribis=, (_Linn._), is the _Aphis_ of the currant. It causes the leaves to present a blistered appearance above; the lice are found on the under side; the wingless are pale yellow, the others have glossy wings, mostly black, with abdomen light green.[35]

=Aphis lanigera=, now called _Eriosoma_, or the Woolly _Aphis_, was first described in 1801 as infesting the apple trees in Germany. It has been noticed in England in 1787, and has since acquired the name of American Blight, from the erroneous supposition that it had been imported from this country; but it was known to French gardeners for a long time previous.

The eggs of this insect are microscopic, and are enveloped in a cottony substance. They are deposited in c.h.i.n.ks of bark, and crotches of limbs, at or near the surface of the ground. When first hatched, the insects are covered with short down; as they grow, the down increases in length. When fully grown, they are one-tenth of an inch long; the head, antennae, sucker, and skins, are blackish, the abdomen of a honey-yellow color. Their punctures produce warty excrescences, the limbs become sickly, the leaves turn yellow and drop off, and the whole tree perishes as the insects spread over it. The remedies appear futile on badly affected trees. Young trees were treated by painting over the affected parts with a mixture of melted resin and fish oil, in equal parts, applied warm. Sir Joseph Banks removed them with a stiff brush. Spirits of tar, turpentine, oil, and soft soap, have been recommended. After sc.r.a.ping off the rough bark, wash the tree with alkaline solution, apply the same to the main roots after laying them bare of earth.[36]

=Phemphigus pyri=, _Eriosoma pyri_, (_Fitch_), or _Pemphigus America.n.u.s?_, (_Walker_), is the Apple-root Blight. It produces a similar condition in the roots, and was also called the American Blight in England. It is composed of warty excrescences upon the roots, containing in their crevices minute lice, having their bodies covered with a white cottony substance. Removal of the earth, and the application of soapsuds, has been recommended as a probable remedy for the injuries done by this insect.[37]

=Psylla Pyri.=--Some _Aphides_ have the power of leaping, like the leaf-hoppers, but they differ from those insects in having very large transparent upper wings, which cover the sides of the body like a steep roof. The genus embracing these insects, is called _Psylla_. One of the species was observed by Dr. Harris, upon a pear tree. They live by suction, and having gorged themselves, the juice runs down on the bark, producing a blackish color; young trees suffered excessively. As Dr. Phumb, of Salisbury, Conn., had observed them in 1833 on some imported pear trees, of which he lost several hundred in a few years, Dr. Harris suspected the insect to be the _Psylla pyri_, of Europe.

Kollar recommends brushing off the insects, and crushing them under foot; and also advises to destroy the winged females in the spring.

This being tedious and uncertain, it is recommended to wash the twigs with a brush, dipped in a mixture of strong soapsuds and flowers of sulphur, before the buds expand, to deter the insects from laying their eggs. A weaker solution, or the whale oil soap, might kill the young insects after they have fastened upon the bark, if applied with a syringe.[38]

=Cicada septendecim=, or the Seventeen-year Locust, as it is erroneously called, is no Locust at all, but should be called _Cicada_, because, as already stated, when considering the order _Orthoptera_, the true Locusts, are, what we call Gra.s.shoppers.

This insect is remarkable for the long period of its pupal existence, which is subterranean, and during which it feeds upon the juices of roots. In its perfect state, it does not eat, and is neither able to bite nor to sting. The injury it does to our orchards is effected by its piercer in depositing its eggs, causing twigs to break and fall off. There are several Harvest-flies that belong to this order.

=Tree Hoppers=, being members of the same order, feed upon the juices of plants, through their suckers, and are thus injurious; but their numbers are not sufficient to render them of much consequence.

=Palaeothrips mali=, (_Fitch_), is the name of an insect described by Dr. Fitch[39] as infesting apple trees in the month of August, where they were attacking the fruit. They excavated a little hollow near the blossom end of the apple about the size of a pea, which was occupied by small insects. Until the habits of the insect are more thoroughly understood, it will be difficult to advise any remedies.

There is quite a number of insects in this cla.s.s that affect the grape vine, some of which may become troublesome, and we should watch their habits. The following accounts are condensed from Dr. Fitch's Report:

=Raphigaster sarpinus=, or the large Green Tree-bug, is gra.s.sy-green, edged with yellow, and a black point at every joint of the abdomen; found in September.

=Pentatoma ligata=, or the Bound Tree-bug, is also gra.s.sy-green, but more widely bordered all round, except the head, with pale red, and has a pale red spot on the middle of its back and on the apex of its scutel; antennae green.

=Arma modesta=, or the Modest Tree-bug, is tawny, yellowish-gray, thickly dotted with brown punctures; the wing-covers are red at the apex of their leathery portion, and have a brown spot at the tip of the hyaline portion; the under side is whitish, with a row of black dots along the middle, and another on each side.

=Thelia univittata=, (_Harris_), or the Single-striped Treehopper, is chestnut-brown, shaped like a beech-nut, with a perpendicular protuberance on the fore part of its back, higher than wide. It is tawny white in front, a white stripe along the back to the tip; length 0.37 inch; July and August.

=Ceresa bubalus=, or Buffalo Treehopper, is of a light gra.s.s-green, freckled with whitish dots; with a sharp short point on each side, projecting like horns.

=Ceresa taurina=, is like the preceding, but the s.p.a.ce between the horns is concave.

=Acutalis dorsalis=, is a small, triangular, shining Treehopper, with a smooth round back; it is greenish-white, with a large black spot, from the anterior corners of which a line runs off to each eye.

Plentiful about the last of July, a few remaining until October.