American Pomology Part 19

In the early stages of their existence, however, the little worms consume only the upper surface of the leaves, and it is at this period that we may most advantageously attack them. The leaves that have thus had their substance eroded become dry and whitish, and attract our attention. They are generally found upon a single twig or spray, usually a lateral, and it should at once be examined, as we may now easily destroy the whole brood by rolling a single leaf between the thumb and finger.

NOCTUae, OR OWLET-MOTHS, CUT-WORMS.

The perfect insects are thick-bodied, and of dull colors; they fly at night. The caterpillars are naked, live in the soil, and feed above ground at night, when they do considerable damage. The common Cut-worm, _Agrotis_, is an ill.u.s.tration. There are several sorts, which have received different names, but the worms all have very similar habits.

The moths are supposed to lay their eggs in July, when they soon hatch and feed during the season; they attain considerable size and hybernate in the soil.

REMEDIES.--Fall and winter plowing has been recommended, as it exposes the worms to the birds, and to the weather, but especially because it destroys the vegetation upon which they might subsist in the early spring. The only safe way, is to watch their traces among our plants, and dig down beside them, find the worm, and destroy it.

Though this does not restore the plant already killed, we prevent further damage, and may hope to thus diminish the pest in future years, which is no small matter. A knowledge of their nocturnal habits has induced some gardeners to go among their young plants with a lamp or candle at night, when they may find the caterpillars feeding. A few choice plants may be protected by wrapping their stems with a strip of paper, or a stout leaf, (hickory), at the time of transplanting into infested grounds; this will save them. Tobacco water has been found very effective, applied to the plants, which it does not injure.

=Mamestra arctica=, (_Hadena amica_, of Harris, and _H. amputatrix_, of Fitch), is a Cut-worm of a brownish color, about one and a half inch long. It is sometimes quite destructive in the nursery and garden, ascending woody plants, and cutting them off where succulent, in the month of May. It can only be checked by seeking for it, in the soil, near the base of the plants affected.

All these Cut-worms are eaten by birds, among which the crow is a valuable aid to the farmer, and should be cherished for his services instead of being condemned as a bird of ill-omen. Predacious insects also consume numbers of them; one of these is the larva of a beetle, _Harpalus calaginosus_. A large Ichneumon-fly has been found hunting after the worms, and is considered their natural enemy.

GEOMETERS, SPAN-WORMS, CANKER-WORMS.

The measuring worms take their name from their peculiar method of locomotion; having their legs at each end of their long bodies, they walk by progressive leaps, arching up their backs by bringing their hind-legs forward, and then thrusting their heads out to their full length. Many of them drop from the trees, and hang suspended by a thread of silk, when disturbed, or when seeking the earth to undergo their transformations. Some of them are naked, or have few hairs; most are smooth, often striped, or of an uniform color, like the bark of the trees on which they feed.

The moths are slender-bodied; the wings large; of some the females have no wings. These are the _Hybernians_, including the Canker-worm, _Anisopterix vernata_. These caterpillars are very numerous and destructive; they do not feed gregariously, and are difficult to combat in that form. The pupae are under ground, and, as the female moths are wingless, and must ascend the trees to deposit their eggs, we can destroy them in the perfect form by meeting them on the highway they have to pa.s.s. Ingenious devices have been invented for this purpose; among the most effective of these are vessels of oil, fastened closely around the bole of the tree. The moths emerge from the ground in early spring, but many come out during pleasant mild days in the winter, and some even in the autumn; so the remedies must be applied early to be of any use.

Harris describes a smaller species as the _Anisopterix pometaria_.

=Hybernia tiliaria=, or the Span-worm of the Linden, is abundant in June, growing to the length of an inch and a half. A belt of tar, applied to the trees, has been found effective in preventing the ascent of the wingless females; this needs renewing daily, until the season of their rising has pa.s.sed.

=Ellopia ribearia=, or the Currant-moth, was figured and described by Fitch as the _Abraxas? ribearia_, in New York Reports for 1856. The worm is light yellow, with black dots. It eats the leaves of currants and gooseberries, in June. The moth ascends from the ground in July; it is nankeen-yellow; quite a common insect in some parts of the country. It must have some natural enemies, for, where very abundant one year, it sometimes disappears altogether the next. Hand-picking is the only remedy known, and this is quite a tedious process.

TORTRICES, DELTA MOTHS, OR LEAF-ROLLERS.

The Leaf-rollers are a numerous tribe, and some of them are troublesome upon our cultivated trees and vines. They curl up the edge of the leaf upon which they feed, and fasten it with little bands of silk, and thus shelter themselves from the weather and from their enemies. They are naked worms, and generally light colored, and exceedingly active. Some live in the unfolding leaves and flower-buds, fastening them together so they cannot expand, while they devour the tender tissues. Some enter the young fruit, which they cause to ripen and fall prematurely. The moths are generally small, often prettily marked, and fly only in the evening.

=Loxotaenia rosaceana=, (_Harris_), is found soon after the buds of the apple begin to expand. They curl up and fasten them together, and do considerable damage.

=Penthina oculana=, (_Harris_), has similar habits, and preys upon the apple; both must be killed by hand.

=Brachytoenia melania=, or the Many-dotted Apple Leaf-worm, is mentioned by Fitch[40] as eating holes in the leaves, in June and September. It is rather thick, light green, an inch and a quarter long, with five white lines and numerous white dots; the worms spin their coc.o.o.ns in a leaf. There are two crops.

=Loxotaenia cerasivorana=, (_Fitch_), or the Cherry Tortrix, is a deep yellow worm, with black head and feet. Found in July, fastening the leaves together and living in families, forming a large nest.[41]

=Desmia maculalis=, or the Spotted-winged Sable, or Grape Leaf-folder, is a slender, active green worm, that feeds upon and disfigures the leaves of our grape vines, rolling them with great regularity, and fastening them with strong bands of beautiful white silk. The pupa is formed within the rolled leaf. These worms begin in June, but continue to fold the leaves during the season of growth.

They can be destroyed by hand-picking, but it requires quickness and dexterity, as the worm escapes from either end of the open pipe when disturbed. The warblers are very fond of them, and destroy a great many.

=Carpocapsa pomonella=, or the Codling-moth, is one of these Tortrices, which gives great trouble. It has been introduced from Europe, but is steadily increasing as our orchards grow older, until we now have few perfect fruit. The moth appears early in the summer to lay the eggs of the first crop of worms. This insect is figured and described by different authors, among whom Dr. Trimble, of New Jersey, has paid it especial attention in his recent work.

The eggs are dropped singly upon the blossom end of the apple, that affords an entrance to the young worm, which pa.s.ses to the core, about which it consumes the pulp and the seeds. The worm is whitish, becoming flesh-colored. In warm weather it attains its growth in three or four weeks, and makes its exit by gnawing through the side of the fruit. It instinctively seeks the stem of the tree to secrete itself under the scales of bark, and this affords us an opportunity to destroy it in the pupa state, for it will creep under any shelter that may be put in its way.

The REMEDIES will depend upon the habits of the insect. The moth, being nocturnal, may be destroyed by burning lamps or fires in the orchard during June, when they are first at work; cheap coal-oil may be used for the purpose. The pupae can be entrapped in large numbers, by putting a piece of old rag in the crotch of the tree, beneath which the worms will crawl to spin their coc.o.o.ns, when they may easily be destroyed. Dr. Trimble has used a trap, made by twisting a hay rope and fastening it about the trunk of the tree; under the rope immense numbers will be found. This trap should be examined fortnightly, as the moths hatch out during hot weather in a shorter time than later in the season, when some remain over winter in the pupal state.

All wormy fruit should be gathered as soon as it falls from the trees, and either be boiled, or at once fed to swine. Hogs and sheep, kept in the orchard, will generally consume the fruit as fast as they fall to the ground; and this is the simplest and cheapest method of destroying the worms.

=Chaetochilus pometellus=, (_Harris_), is commonly called the Palmer-worm. It feeds upon the leaves of our orchard and forest trees in June. Sometimes it appears in immense numbers, and, coming after the period for the production of new leaves, great damage is done to the trees; old trees, and limbs of younger ones, are sometimes killed.

There have been two celebrated invasions of this insect in the Eastern States, those of 1791 and of 1853.[42]

GRAPE VINE FEEDERS.

Grape vines are subject to the attacks of many lepidopterous insects.

Dr. Harris gives the history of seven American larvae, mostly of large moths, which feed upon grape leaves.

=Pterophorus periscelidactylus=, or the Gartered Grape vine Plume, is a pale green worm, half an inch long, which hides itself in a hollow ball of leaves, fastened together with silken threads. It is described at length by Dr. Fitch, in the New York Agricultural Transactions.

=Ohis myron=, (_Chaerocampa pampinatrix_, of _Harris_), called also the Vine Dresser, is somewhat troublesome in the vineyards, as it eats the leaves, and cuts off the bunches of grapes when half grown. This worm is thick, cylindrical, tapering anteriorly, pale green, freckled with pale yellow dots, and, when mature, a pale dusky olive; 2.25 inches long. The pupa is found under leaves on the ground; the moth emerges in June.

=Philampelus satellita=, and =P. Achemon=, the Satellite and Achemon Sphinges, are large green worms that feed upon the vine. They bury themselves in the ground when going into the pupa state, and remain until the next July. The worms are seen in August and September.

=Procris Americana=, or the American Forrester, is found feeding upon the grape leaves at mid-summer, (June 22). The worms feed gregariously on the surface of a leaf, some twenty side by side, leaving only a skeleton behind them when small, and consuming the leaf when older.

They are small, 0.60 inch long; yellowish. The moth is blue-black, with a bright orange neck.

=Alypia 8-maculata=, or the Eight-spotted Forrester, is a light blue worm, 1.25 inches in length. They leave the vines in July, and spin a web on the ground; the moth appears in May; it is black, with orange shanks; each of the fore-wings has two large, light yellow spots; the hind-wings have two white ones. Width 1, to 1.50 inch.

aeGERIANS.

=aegeria exitiosa=, (_Say_), or _Trochilium exitiosum_, is well known in its larval state as the Peach tree Borer, and is often so destructive as to kill the trees. The habits of the worm as a borer, and its situation at the base of the tree, are somewhat similar to those of the apple tree borer; but while that is the footless grub of a beetle, this is a true caterpillar, the larva of a b.u.t.terfly or moth, with feet. The females deposit their eggs from June to October, placing them upon the bark at the surface of the ground, sometimes in the forks of the large limbs. The larva enters, and works downward; first consuming the bark, but afterwards eroding the wood also. Gum exudes from the wound, mixed with their castings, and indicates their presence. When ready to enter the pupa form, the worms come to the surface, excavate a hollow in the wood, and prepare a tough leathery follicle or pod, three-fourths of an inch long, in which they repose as pupae.

This, or an a.n.a.lagous insect, attacks the plum tree, and behaves in a similar manner. The double-flowering Almond of our shrubberies is also attacked by the borer.

The perfect insect looks more like a wasp than a b.u.t.terfly, for the wings of all this group are partially clear of feathers, and transparent. It varies in size from a half to three-quarters of an inch in length, and from eight-tenths to one and three-tenths of an inch across. The female varies more than the male, and her wings are larger in proportion to the body, which is heavier. The male is of a deep steel-blue color, with sulphur-yellow marks, and glossy l.u.s.ter.

The wings are transparent and glossy; the veins margined and fringed steel-blue.

REMEDIES will depend upon the habits of the insect, and must be directed to the pupa and larva, though valuable preventives are applicable to the perfect insect. The worms may be sought out by sc.r.a.ping away the gum and cutting the dead bark until we find them, often along the main roots; the follicles with the pupae should also be sought. This work can be done in the autumn and spring; if at the former season, the removed earth should be left away from the stem, when coal tar may be applied to destroy any worms left in the tree and to act as a preventive against future attacks, but this substance should be used with great caution. If applied, the earth should be thrown back to the tree. Boiling soap-suds has been used with good effects.

PREVENTIVES are sometimes better than cures, and in this case they have been very successfully used. They all consist in means to keep the moth from depositing her eggs in the part of the tree where, alone, the borers can be harmful. Some raise a little mound of earth about the tree in the spring, and allow it to remain there all summer.

The first application of this principle consisted in placing a chimney crock about the base of the young tree when planted; into this coal ashes, cinders, or even gravel was placed, which protected the base of the tree. In the autumn the crock was lifted, and the materials scattered. An open box, made of four bits of board, tacked together, answered the same purpose. A cone of coa.r.s.e brown paper, tied about the tree with grocers' string, or pasted upon the tree itself, when applied, will answer a very good purpose in keeping off the fly.

A small portion of sulphur thrown about the tree is said to have the desired effect, but the statement has not been confirmed by trial. It has been recommended to plant Tansy with every peach tree, but doubt attaches itself to this suggestion also.

In the _American Agriculturist_, for February, 1865, is a notice of a peach tree protector made of sheet-iron, like a stove-pipe; and in the April number, Mr. Bouthorpe, of Ma.s.sachusetts, says, he had used a similar apparatus made of zinc, eight inches long, and twice the size of the tree, which was of easy application; the contained s.p.a.ce next the tree was to be filled with loose dirt. They were found to be a perfect protection.

=aegeria tipuliformis=, (Linn.), or the Currant Borer, has been imported from Europe. The eggs are laid near a bud; when hatched, the worms penetrate the pith of young shoots, killing them.

=aegeria pyri= is mentioned by Dr. Harris[43] as having done a good deal of damage to pear trees, by boring under the bark. The perfect insect resembles that of the Currant Borer, and makes its appearance near the end of summer, leaving its chrysalis skin projecting from the hole in the bark, whence it had escaped.

=aegeria polistaeformis=, or Grape Vine Borer, is mentioned by Mr.

Glover in the Patent Office Report for 1854, p. 80. He had received it from North Carolina, where it was very destructive to all vines, except the Scuppernong. This insect has become rather common in the vineyards about Cincinnati, and its depredations, in consequence of the large size of the caterpillar, are very serious. The eggs are laid near the roots of the vine, and the larvae bore into the bark and wood during the summer, consuming them so completely, that the vine sickens and dies, and often breaks off at the ground, or just below the surface. When fully grown, they measure from an inch to an inch and three-quarters in length, are thick and whitish, and they form a pod-like chrysalis, similar to that of the Peach Tree Borer, but within or beside the injured roots.