The best remedy will be found in encouraging insectivorous birds—the lark, rook, starling, peewit, and others, eating them either in the egg or young state with great avidity; a good assistance to whose labours may be supplied in a few broods of ducks from the farmyard, which it will pay well to have tended by a good boy—where such can be found—as these birds are most efficient as destroyers of slugs and caterpillars.
Store pigs turned into old leas, where they can do no mischief, will get no bad living where snails and insects abound.
Wire-worms.—The several species of beetle which produce the wire-worm belong to the genus Elater. They are of a long oval shape: about half the length belongs to the head and thorax, and the other to the abdomen. Every schoolboy knows that when he holds the insect on its back it elevates the abdominal portion, and again lets it fall so as to make a beating sound; and hence its generic name, and also its common name of click-and-hammer beetle. If he remove his finger when in this position, the creature immediately skips up and turns on its feet, from which action it has got the name of “skipjack.”
Curtis has estimated nearly seventy species of click-beetles as producing wire-worms in this country; but the three following are those generally met with—Elater lineatus, E. obscurus, and E. ruficaudis. These all attack corn and almost every other kind of vegetable.
The larvæ of these are very much alike, being hard, leathery, wiry caterpillars, which vary in length to about three-quarters of an inch, according to age. These are mostly smooth, and have six feet on their thoracic segments, and a false foot or proleg in the middle of the underpart of the terminal section of the abdomen—characters by which wire-worms may be distinguished from all others. Their length varies with age; as they live for some years in the larva state, so the different sizes mark so many broods, which in some fields are annually provided for. It should here be observed that the wire-worm does not breed; these larvæ can only be hatched from the eggs of the female click-beetle: hence, then, destroying the worms prevents the development of their parent.
Now, as we have seen whole fields of wheat destroyed by wire-worms, it becomes important to examine the nature of this attack, with a view to point out a remedy. If, then, we go into a corn field in early spring, and see the young wheat blades looking yellow and sickly, we shall seldom be long in finding the wire-worm, on carefully taking up some of the affected plants. Its position will be at the base of the plant, sometimes eating its way into its centre, and so eating out its very heart; or perhaps it may nibble away the outer coat of the young stem, and so prevent any nutriment passing into the blade. One worm will be enough to kill a single blade; but, alas! it frequently happens that he either visits all the blades, or is assisted by many individuals to each plant. This abundance we have observed more particularly on the breaking up of old pastures, old seeds, or saintfoin lea, in which not only have we many broods of wire-worms, but the eggs of a fresh lot, which hatch in time to eat the spring wheats. Again, this large increase we have ever observed in districts where rooks are few or much molested. The rook is a constant visitor to the clover field; but when the plant is young he is driven off, because the farmer “cannot think what else he can come for but the clover buds;” and when he sees some of these strewing the ground where the birds have been, he is confirmed in his opinion: but, if he carefully looked at the buds themselves, he would find them of a sickly hue, however recent the attack, and, if he looked deeper he might find the real enemy.
Fortified, then, with repeated observations of this kind, if asked how best to keep under wire-worms, we say most unhesitatingly, encourage the rook: he is one of the farmer’s best labourers; and though, like John, and Dick, and Hodge, he will sometimes run into mischief, it is surely better to institute a judicious police than to condemn and execute without very strong evidence.
Yarrell, in his beautiful “British Birds,” has the following remarks upon this highly-important subject:—
The attempts occasionally made by man to interfere with the balance of powers as arranged and sustained by Nature, are seldom successful. An extensive experiment appears to have been made in some of the agricultural districts on the Continent, the result of which has been the opinion that farmers do wrong in destroying rooks, jays, sparrows, and, indeed, birds in general on their farms, particularly where there are orchards. In our own country, particularly on some very large farms in Devonshire, the proprietors determined, a few summers ago, to try the result of offering a great reward for heads of rooks; but the issue proved destructive to the farms, for nearly the whole of the crops failed for three successive years, and they have since been forced to import rooks and other birds to stock their farms with. A similar experiment was made a few years ago in a northern county, particularly in reference to rooks, but with no better success; the farmers were obliged to reinstate the rooks to save their crops.
But as, perhaps, the most interesting account of the value of rooks will be found in an extract from the Magazine of Natural History, vol. vi. p. 142, we cannot do better than transcribe it:—