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and suckers. The larvæ hatch out about four weeks later, feed for about other four weeks, then pupate on leaves, and emerge as beetles about the end of August. In October they hibernate under moss or dead leaves, then reappear and pair in the following May. The generation is therefore simple and annual. In Central Europe, however, it often has a double generation.
Prevention and Extermination.-The beetles may be shaken or rapped down from trees while pairing in May or June, or else from August till October, between the time of emerging and of hibernating. Spraying the Osier-shoots and the soil beneath them with insecticides is often effective (see pp. 106, 124, and 132).
2. The Aspen-leaf Beetle, Chrysomela (Lina) tremulæ, is very much like C. populi in appearance and life-history, except that it is only about of an inch long, and has no black tips at the top-ends of the wing-cases. It is also usually somewhat more destructive than the larger insect, because it attacks the shoots while still young and soft. The larvæ and pupæ are hardly distinguishable from those of C. populi.
3. The Willow or Osier Beetle (Phratora vitellina) occasionally does a good deal of damage by defoliating Osiers.
Appearance. The beetle is about to of an inch long, bronze, green, or coppery in colour, and oblongly-oval in shape; the wing-cases have rows of fine punctures.
Life-history. The beetles fly in late April, May, and June, pair, and lay their large oblong eggs in clusters of about 10 or 12 on the lower side of osier-Willows, tree-Willows, and Poplars. On hatching out about four weeks later, the larvæ skeletonise the leaves, destroying both the spring and afterwards the summer flush of foliage before descending to the ground to pupate. The beetles emerge in August, feed for some time, then hibernate either in the ground or in bark-fissures, or in almost any other kind of hiding-place. The generation is usually single, though sometimes the early-comers in August pair and produce a second brood before the time for hibernation arrives.
Prevention and Extermination.-As for Chrysomela populi.
4. The Blue Alder-leaf Beetle, Chrysomela (Agalastica) alni, is a small violet or steelblue beetle, about of an inch long, with black antennæ, thorax, and legs. The 6-footed larva is less than an inch long, and blackish with greenish lustre, rather hairy, and with transverse dorsal marks across the abdominal segments.
The beetles fly in May and June, and the larvæ hatch out in June. Both beetles and larvæ feed on Alder foliage, and are sometimes troublesome in nursery-beds. The beetles should be collected during May and June, and again after August.
5 and 6. The common Earth-flea (Haltica oleracea) and The springing Oak-leaf Beetle (Haltica eruca) are minute insects only about to of an inch long, and bluish-green, with finely punctured wing-cases. They are sometimes destructive in gardens and nurseries, and can best be exterminated by sprinkling the beds with ashes or lime, or watering them with a weak solution of carbolic acid or a decoction of wormwood.
G. Click-Beetles or Skip-Jacks (Elaterida).-These beetles derive their common names from the peculiarities that if one end of the beetle be held firmly, it bends its body with a clicking sound, and that if laid on its back, it rights itself by springing up in the air with a click. The beetles eat acorns, beech-nuts, and seeds of other broad-leaved and of coniferous trees, and may be destructive to young shoots; but the larvæ, known as "wire-worms," are very destructive to the roots of plants in nurseries. As they are omnivorous, and remain for at least three years as larvæ, it is difficult to exterminate
them when once they have obtained possession of nursery-beds. The attacks of wire-worms in nurseries are worst during a cold wet May, and are least to be feared during warm spring weather when the young plants grow vigorously. Wire-wor vorms are far more injurious to the farmer than to the forester. They feed on roots and young stems at all times of the year, except during very hard frost, when they burrow deep into the ground.
The beetles are long, narrow, and hard, very much like the Buprestida, but mostly without their metallic sheen; abdomen with five segments; antennæ 11-jointed, filiform in female, serrate or pectinate in male; legs short and weak, tarsi with five joints. Larvæ ("wire-worms") 6-legged, long, narrow, and brownish-yellow, with flat, brown-black, horny heads, and a prominent tubercle on the terminal segment. They live in or on the ground for three years or longer. Pupa in small earthy cocoons deep in the ground. Generation from three to five years, probably mainly according to the amount of food available for the larvæ.
1. The Striped Click-Beetle (Agriotes lineatus) is the commonest and the most destructive species (Fig. 158, 1 and 1a).
Appearance. The beetle is of an inch long, with a wing-expanse of slightly over an inch; thorax tawny; wing-cases brown, with yellowish
I and 1a. Agriotes lineatus.
2 and 2a. Agriotes sputator. (Natural size and magnified.)
3 and 3a. Agriotes obscurus.
4. Wire-worm, larva of Agriotes lineatus. 5. Pupa. brown lines; antennæ reddish-yellow; legs brown.
The larva, or "wire-worm," is from to of an inch long, very shiny, and yellow (but becoming almost chestnut when dead), with a few hairs on its body, three pairs of 4-jointed legs on the first three segments, and a swelling on the lower surface of the terminal segment. It has strong jaws adapted for biting through roots.
Life-history. The beetles are found under stones, in grass-roots, on grasses, flowers, and trees, in hedges, &c. They fly in July and August, and (like the cockchafer) lay eggs in the earth, in nurseries, and wherever the soil has been turned up and loosened. Some of the beetles hibernate in sheltered places, and pair in the following May and June. The wire-worms which hatch out live in the earth, near the roots of the plants on which they feed.
After feeding for three to four years, according to circumstances, the larva goes down deep into the earth and pupates in the month of July in a small oval earthy cocoon, from which the beetle emerges two or three weeks later.
Prevention and Extermination.-Once the ground is infested with wire-worms
little can be done to check their attacks for the time being; but dressings of nitrate of soda may help to prevent eggs being laid in nursery-beds. In nurseries the beetles may be trapped by laying small heaps of lucerne, clover, or sainfoin on the ground, and covering them with tiles or pieces of board during May and June, as long as beetles are noticeable. They fly to these heaps, shelter beneath the green material (particularly if the ground is clean), and lay their eggs there. These traps must be examined as often as possible, to collect the beetles (up to 100 have been taken from one trap in a week), while the green stuff should be destroyed every ten days, and the ground beneath well beaten down to squash any eggs left there. Boards or tiles placed beneath the bait prevent eggs from reaching the ground.
The larvæ can also often be trapped by laying down pieces of beetroot under the earth in nurseries, marking the spot with a peg, and examining them every few days, and killing the wire-worms found buried in the baits.
Leaf-mould and manure-heaps should never be allowed to have weeds growing on them, but should be covered with a coating of gas-lime to prevent the beetles laying their eggs there. Plovers especially, also rooks, starlings, and jackdaws, assist greatly in destroying wire-worms.
It is desirable to examine the ground selected for the nursery, and to reject the plot if it appears badly infested, or to cleanse it thoroughly before planting. As the acreage required is small, there should be no difficulty in doing this by methods known and practised in agriculture, such as paring off and burning two inches of the top-soil early in autumn, or dressing with gas-lime, chloride of lime, or ammoniacal waste, and leaving it fallow till the effect of the poison has worn off. Fallow land kept clean and free from weeds during the period of egg-laying in June will have comparatively few wire-worms, but in the absence of better food these probably feed on humus, especially when young.
If seedlings are actually attacked, handpicking is a good remedy when facilitated by the use of potatoes, carrots, or sliced mangold, laid on the ground as a bait and regularly visited. A dressing of rape-cake or mustard-cake, popular in hop-growing, may be tried, but the value of it under these circumstances remains to be proved. Serious injury from wire-worm is unlikely to extend beyond the first year of growth.-(Blandford.)
For further details, see also Board of Agriculture Leaflet No. 10 (Wire-worms).
2. Agriotes sputator and A. obscurus, the former somewhat smaller and the latter rather thicker and of stouter build than A. lineatus, are two other clickbeetles whose appearance and habits are much the same as above described. The beetles feed on acorns and other tree-seeds, while the wire-worm larvæ infest nurseries and young plantations (Fig. 158, 2, 2a; 3, 3a).
II. Moths and Butterflies (Lepidoptera).1
This order of "scale-winged" insects derives its name from the ordinary membrane of their wings being covered with a number of minute scales, set over
1 The order Lepidoptera is divided into the two great classes of Moths and Butterflies, which may thus easily be distinguished :
Very few of the Butterflies are destructive to forest trees, and that only slightly. One such is the large Tortoiseshell Butterfly (Vanessa polychloros), with a wing-span of 21 to 24 in. It is of a yellowish-red above with dark-brown edges; the fore-wings are
lapping like the tiles on a house-top. These scales are generally of brilliant colour.
Large numbers of moths do great damage to woodland trees; but mention can here only be made of the more important kinds which are destructive in the woods and plantations throughout Great Britain and Ireland.
A. Spinners (Bombycidae).
This family includes some of the most injurious moths, whose voracious caterpillars are sometimes enormously destructive to foliage in the coniferous forests of Central Europe.-Moths usually nocturnal species, with large wings and long thick bodies, mostly densely haired, and female generally larger than male; antennæ short, pectinate in female, doubly pectinate in male. Eggs often laid in clusters, and covered with fluff from the tail of the female. Caterpillars 16-legged, usually hairy. Pupa short and thick, enclosed in a silky cocoon, into which the larval hairs are often spun. Generation annual.
1. The Hop-Dog, Pale Tussock Moth or Beech Spinner, Bombyx (Orgyia, Dasychira) pudibunda.-The Hop-dog or Beech-moth is a common insect in England, and may occasionally be found on most kinds of broad-leaved trees, but it mainly attacks the Beech, and is its chief insect enemy. It is often also destructive in the hop-gardens of Southern England. Its attacks are mainly confined to old Beech-woods growing on poor soil, and it usually only migrates to pole-woods and younger crops after the old woods have been defoliated. As the caterpillars feed mostly during late summer, after the young buds for the next year's flush of foliage have already been formed, the damage is less than would otherwise be the case; and though the generation is simple and annual, an attack seldom extends beyond two consecutive years.
Appearance. The wings of the female span 2 to nearly 24 inches, while the somewhat smaller male is distinguished by yellowish-brown feathery antennæ. The fore-wings and front part of body are reddish- or greyish-white, with two or three dark, waved, transverse stripes; hind-wings and lower part of the body are lighter, with a faint, broad, greyish, transverse band.
The 16-legged caterpillar is, when full grown, about 1 inch long. It is at first greenish-yellow, becoming brownish or reddish. It is easily known by four thick, yellowish- or brownish-grey tufts of bristles on the fourth, fifth, sixth, and seventh segments, between which are velvety black bands, and by a long rose-red or ruddy-brown tuft of hair on the second last segment.
The dark brown to greyish-yellow hairy pupa rests in a cocoon spun with the hairs of the larva.
Life-history.-The moth flies late in May and early in June. The female lays about 100 eggs or more on the smooth bark of poles or trees, and usually within about 3 to 10 feet off the ground. The eggs are at first greyish-green, darkening to a brownish- or bluish-grey. About three weeks later, in June or July, the young caterpillars hatch out, eat their egg-shells, and cluster in colonies for a few days before scattering and ascending to feed on the foliage. They only gnaw the
spotted with black, three spots being on the yellow ground; the hind-wings have a large black spot on the upper edge, and a blue moon-spot near the fringe. The greyish-blue caterpillar is about 1 in. long, with yellow dorsal and side stripes and rusty yellow prickles. The pupa is angular, reddish-grey, and with several mother-of-pearl spots. After hibernation the female in spring lays clusters of blackish-grey eggs on the twigs of fruit-trees, but also on Elm, Willow, and Aspen. The caterpillars hatch out in May and June, live in colonies in nests, and feed on the foliage till the end of June, when they scatter and pupate.
leaves slightly at first, but with growing strength devour more of them, and often gnaw them completely through near the petiole, so that the ground is often strewn with parts of leaves. Towards the end of September or early in October they come down from the trees to form cocoons in moss or under dead leaves, herbage, &c., where they hibernate as pupæ.
Preventive and Exterminative Measures.-Insectivorous birds (crows, cuckoos, thrushes, finches, tomtits, &c.) and predatory and parasitic insects (Carabidæ and Ichneumonidae chiefly) prey on the caterpillars; but the sudden cessation of attacks is mainly due to a fungous disease (Isaria farinosa) infecting the caterpillars. The latter are also very sensitive to sudden changes to cold and wet weather, although hardy as regards snow and cold in winter. It is not of much practical use to try and collect the pupa or kill the caterpillars when descending to pupate on the ground. The egg-clusters laid on the smooth Beech-stems within about 10 feet of the ground can, however, easily be collected and crushed; or the eggs and clusters of tiny caterpillars can be destroyed by a daub of patent tar. Grease-banding the stems about 12 feet with narrow rings will prevent most of the caterpillars from getting up to the crown to feed on the foliage, and will also hinder those hatched out from eggs laid above that from being able to descend for pupation on the ground.
Two other Spinners, the Brown-tail Moth and the Lackey Moth, of the tribe called "Tent Caterpillars," from their forming tent-like silky nests while the young larvæ still live in clusters or colonies, also attack Oak, Elm, Hawthorn, and other woodland trees and shrubs, though the chief damage they do is to Apple-, Plum-, and Pear-trees in orchards throughout Central and Southern England.
2. The Brown-tail Moth, Bombyx (Liparis, Porthesia) chrysorrhæa, is a shining white moth having a wing-span of about 1 to 1 in. In the female the abdomen is mostly brown, with a thick red-brown woolly tuft near the end, while the male is blackish-brown with a red-brown woolly tuft at the end. The 16-footed caterpillar is not quite 1 in. long. It is dark grey-brown above, with two irregular red stripes along the sides, and covered with tufts of yellowish-brown hairs; it is grey beneath, with yellow marbling. The hairy pupa is dark-brown, and has a pointed tail.
Life-history. The moths fly late in June and early in July. The female lays about 200 to 300 brownish-yellow eggs, on the lower surface of the leaves of Oak chiefly, but also other kinds of broad-leaved trees, and covers them with spongy wool from her thick tail. The caterpillars hatch out in August, and form "tents" or colony-nests round the young shoots and leaves. In autumn they strengthen these and form tough nests of about the size of a fist, where they hibernate. In spring they again feed on the foliage, returning to their "tents" at night-time or during bad weather; but about the middle of May they abandon these and wander about freely to feed. Early in June they pupate for about three to four weeks in a greyish-brown transparent nest made between the leaves. They have therefore a simple annual generation.
Preventive and Exterminative Measures.—In orchards the winter nests can easily be destroyed, but this is not practicable in the crowns of high Oaks, &c.
This pest can be annihilated in orchards by spraying with Paris-green wash or London-purple (lb. to 100 gallons water, then 1 lb. lime thoroughly mixed and well stirred), and arsenate of lead (see Board of Agriculture Leaflet No. 69, on Tent Caterpillars—the Lackey Moth and the Brown-tail Moth).
3. The Lackey Moth, Bombyx (Gastropacha, Clisiocampa) neustria.-This moth has a wing-span of about 1 to 11⁄2 inch. Its body and fore-wings are yellow or reddishbrown, with a broad, light-edged transverse band; the hind-wings are somewhat lighter, and crossed in the middle by a faint darker band. The caterpillar is slightly haired, and about 1 inch when full-grown. It is marked with alternate stripes of light blue, reddish-brown, and white (like a lackey's waistcoat, hence its name); its head is paleblue, with two black spots.
Life-history.-The moths fly, towards evening, in July and August. The female