Wireworm

“ Among the Coleoptera or beetles there is a group of world-wide pests, the Elateridae or click beetles, the adults of the various “wireworms.” The insects in the larval or wireworm stage attack the roots of plants, eating them away below the ground. The eggs deposited by the beetle in the ground develop into yellowish-brown wire-like grubs with six legs on the first three segments and a ventral prominence on the anal segment. The life of these subterranean pests differs in the various species ”

“ Wireworms, which are such a foe of the carnation grower, may usually be destroyed by spreading gas-lime at the rate of two pounds per square yard over the unoccupied soil in the fall, ploughing or digging it into the ground a month or two later. If this is impracticable, the wireworms may often be trapped by burying pieces of potato at intervals, removing them every few days. ”

“ Slugs, and how to trap them—Blight or green fly—Earwigs—Wireworm—Snails—Mice—Friends mistakenly called foes.
The best garden as a rule has the fewest insects, indeed, no foe is allowed to lodge for any length of time without means being taken for its extermination. Some enemies are more easily got rid of than others; for instance, green fly, or aphis (to give it the scientific name) , rarely attacks healthy plants to any extent; it goes for the sick ones, therefore good cultivation will speedily reduce their numbers. ”

“ Between these two extremes we find various transitional forms: an active larva, as described above, but with four-segmented, single-clawed legs, as among the rove-beetles and their allies; the body well armoured, but slender and worm-like, with very short legs as in wireworms and mealworms (figs. 18, 21 b) ; the body shortened, with the abdomen swollen, but protected with tubercles and spines, and with longish legs adapted for an active life, as in the predaceous larvae of ladybirds ”

“ Most of the adephagous larvae (fig. 13) have a pair of stiff processes on the ninth abdominal segment, and the insect, from its general likeness to a bristle-tail of the genus Campodea, is often called a campodeiform larva (Brauer, 1869) . From such as these, a series of forms can be traced among larvae of beetles, showing an increasing divergence from the imago. The well-known wireworms—grubs of the Click-beetles (Elateridae) —that eat the roots of farm crops, have well-armoured bodies, but their shape is elongate, cylindrical, worm-like ”

“ The grubs of the Chafers (Scarabaeidae) are also root-eaters, but they are less active in their habits than the wireworms, and the cuticle of their somewhat stout bodies is, for the most part, pale and flexible; only the head and legs are hard and horny. Usually an evident correspondence can be traced between the outward form of any larva and its mode of life. For example, in the family of the Leaf-beetles (Chrysomelidae) some larvae feed openly on the foliage of trees or herbs, while others burrow into the plant tissues. ”

“ INSECT AND OTHER PESTS Vigorously growing plants are far less liable than are feeble ones to the attacks of the various living enemies which the gardener is called upon to combat. Therefore the most important item in the suppression of insect or fungoid pests is careful and correct culture. But, even in the best kept gardens, green-fly and earwig, slugs, snails and wireworms will appear, and must be dealt with by repressive as well as by preventive measures. ”

“ Autumn is the proper time for doing this work, and the ground should be left rough, so that it may benefit by winter frosts. Wireworms are deadly enemies to the Gladiolus corms, and an effort should be made to clear them out. Happily, they will flock to traps such as Potatoes and Rape cake, and their destruction is a mere question of daily attention. ”

“ So far as the interests of farming is concerned, it will be observed that the above recommendations do not in any way clash with the best cultural methods. There is good reason for believing, too, that they will prove of value in the destruction of wireworms. ”

“ When mature they pass deep into the ground and pupate, appearing after a few months as the click beetles (fig. 1) . Most crops are attacked by them, but they are particularly destructive to wheat and other cereals. With such subterranean pests little can be done beyond rolling the land to keep it firm, and thus preventing them from moving rapidly from plant to plant. A few crops, such as mustard, seem deleterious to them. By growing mustard and ploughing it in green the ground is made obnoxious to the wireworms, and may even be cleared of them. ”

“ Their muscular power renders them expert in burrowing, and they are well protected by their horny jackets. When their term of feeding is completed, they descend to a considerable depth and change into the chrysalis state, from which they come forth as jumping beetles in the course of July and August, a certain proportion remaining in the ground to complete their final change in spring. Their power of destruction is then at an end. They resort to flowers, lead a merry life for a short time, and when they pass away leave plenty of eggs to continue the race of Wireworms. ”

“ We do not know any easy way with wire worms. Nitrate of soda is believed to kill or repel them, but you have to be careful with it, for too much will either over-stimulate or kill the kill; about 200 pounds per acre, well distributed, is the usual prescription for the good of the plants. Wire worms can probably be killed with carbon bisulphide, using a tablespoonful poured into holes about a foot deep, three or four feet apart. The vapor would permeate the soil and kill all ground insects, but the acre-cost of such treatment must be measured in its relation to the value of the crop. ”

“ One of the most unusual of all luminous creatures is an insect larva found by farmers ploughing damp soil in Brazil and Uruguay. It is a reddish-brown little worm with rows of green lights on both sides and a vivid red lamp on the front of its head. The red light is actually red—not white light shining through a reddish skin. Adult females of the species retain the same luminous pattern. Male adults have only feeble, yellow lights. The larva are extremely vicious little creatures, predators on white grubs which infest the soil. ”

“ Wire-worms are the grubs of skip-jack or click beetles, perhaps the most injurious of farm pests. They are called wire-worms “from their likeness in toughness and shape to a piece of wire;” they are yellowish in color, from one-quarter to one-half an inch in length, with three pairs of legs, and a suctorial appendage below the tail. The eggs are laid near the roots of plants, in the ground or in the axils of leaves ”

“ The majority of these larvae live in decaying wood, but some are found in the earth; as a rule the growth is extremely slow, and the life of the larva may extend over two or more years. Some obscurity has prevailed as to their food; it is now considered to be chiefly flesh, though some species probably attack decaying roots; and it is understood that wire-worms destroy the living roots, or underground stems, of the crops they damage. ”

“ They have in reality come from the bodies of insects in which they pass their young or larval stages as parasites. The hair-worms all live as parasites during their larval stage, and as free independent animals in their adult stage. Some of them require two distinct hosts for the completion of their larval life, living for a while in the body of one, and later in the body of another. The first host is usually a kind of insect which is eaten by the second host. The eggs are deposited by the free adult female in slender strings twisted around the stems of water-plants. ”

“ We spray before the blossom opens, for bud moth, canker-worm and tent-caterpillar, and after the petals have fallen for codling-moth, tussock-moth, and fall web-worm. We have been successful except as to bud moth and fall web-worm. We believe we have greatly reduced the codling-moth by spraying, and we know we have destroyed the canker-worm. Have never successfully combated borers, excepting with knife and wire. Fall web-worms are burned in the tree with a gasoline torch, or the small limbs with webs are removed and burned. ”

“ Others, and this is the most common mode of parasitism, attack the insect in its larva state; others, in the pupa state, and still others in the perfect, or imago state. Dr. Leidy has shown that the wood-devouring species of beetle, Passalus cornutus, and some Myriopods, or "thousand legs," are, in some cases, tenanted by myriads of microscopic plants and worms which luxuriate in the alimentary canal, while the "caterpillar-fungus" attacks sickly caterpillars, filling out their bodies, and sending out shoots into the air, so that the insect looks as if transformed into a vegetable. ”

“ Very good illustrations of this kind of work are afforded by the rascal leaf-crumpler and the common bag worm, both of which in the larva state live in cases, and are much affected by parasites, and neither of which can survive if the cases are plucked in winter and placed away from any trees or shrubs, while under these circumstances the parasites will perfect and escape.
It is quite different with the second method of dealing with beneficial insects which I have mentioned, for here man has an opportunity of doing some very effective work. ”

“ The larvæ of many insects are destructive to wood. Some attack the wood of living trees, others only that of felled or converted material. Every hole breaks the continuity of the fibres and impairs the strength, and if there are very many of them the material may be ruined for all purposes where strength is required.
Some of the most common insects attacking the wood of living trees are the oak timber worm, the chestnut timber worm, carpenter worms, ambrosia beetles, the locust borer, turpentine beetles and turpentine borers, and the white pine weevil. ”

“ The female glow-worm, the light-giver, is wingless; the male is winged. The latter, however, has but little of the light emitting power possessed by the female. Only the light-givers are collected, and being destitute of the first attribute of an insect, wings, are set down in popular parlance as worms. Old mossy banks, damp hedgerows, and shaded woods are the loved haunts of the fireflies, and the warm nights of the soft summer months most induce them to burn their soft lustre. Some widowed worm or firefly flirt may shed her luminous self in the darkness even on into dying summer or autumn. ”

“ When the worm hatches, it enters the wood and traverses it longitudinally until it is ready to assume the mature or beetle state, when it comes to the surface and makes its escape. These worms will frequently riddle an entire branch and even enter the trunk. The apertures that the beetle makes for the laying of its eggs are so small—more minute than the head of a pin—that discovery and probing for the worm with a fine wire is not as fruitful of results as has been claimed. ”

“ As they leave the bodies of their hosts they fall to the ground, and crawl away into the deeper and moister parts of the soil. Threadworms found in the damp earth, in digging up gardens and cutting ditches, have often been brought to me, which presented no external distinctions from the threadworms of insects. This suggested to me that the wandering threadworms of insects might instinctively bury themselves in damp ground, and I therefore instituted a series of experiments by placing the newly-emigrated worms in flower-pots filled with damp earth. ”

“ Yet their life is full of danger. A keen-eyed population of blackbirds, thrushes, starlings, peewits (plover) , and partridges are always watching for and preying upon the poor worm. Even in his burrows, which may be six feet deep, he is not safe, for the mole (moudiewarp) is also both very hungry and very active, and delights in eating him.
In the soil also and even deeper in the subsoil are many insects; some hibernate in the winter, and at other times actively gnaw the roots of plants or devour dead leaves and twigs (see Chapter xxiii.) ”

“ Manson’s view as to the mode of development of the worm be substantiated, then naturally the area of the disease must necessarily be limited to the regions in which the intermediate insect host is to be found.
The fully grown worm may, judging by some of the cases recorded, infest the human subject for a good many years, and may yet not give rise to any very serious symptoms. It possesses very considerable locomotive powers. ”

“ Earth-worms are more plentiful in moist land, such as pastures, etc., than in that which is cultivated; in gardens, also, they exist in vast numbers. When it is desirable to take worms in quantities, it is only necessary to thrust a stake or three-pronged fork into the ground, to the depth of about a foot, and to move it suddenly backward and forward, in order to shake the soil all around; the worms are instinctively terrified by any motion in the ground, and, when disturbed, hasten to the surface. ”

“ This type of insect gradually gave rise to the orders which now contain the largest number of species, including the beetles, moths, and flies. In many lines of this neuropteroid branch, as it is called, the larva has become adapted to a mode of life quite different from that of the adult. Many fly larvae, for example, live in rotting organic material or live as parasites within the tissues of other kinds of insects, whereas the adult flies often feed at flowers on pollen and nectar, visiting the site of the larval habitat only to lay eggs. ”

“ By infecting man or animals who ingest it. It is thus, for example, that man, dog, or cat, becomes infected with the double-pored dog tapeworm, Dipylidium caninum. The cysticercoid stage [Pg 5] occurs in the dog louse, or in the dog or cat fleas, and by accidentally ingesting the infested insect the vertebrate becomes infested. Similarly, Hymenolepis diminuta, a common tapeworm of rats and mice, and occasional in man, undergoes part of its life cycle in various meal-infesting insects, and is accidentally taken up by its definitive host. ”