This section is from the "The New Student's Reference Work Volume 5: How And Why Stories" by Elinor Atkinson.
Wheat has three insect enemies—the chinch bug, the Hessian fly and the wheat midge. When ground into flour the meal worm often hatches out and makes it unfit for use. On the potato plant is the Colorado beetle that eats the leaves, so they cannot make plant food. The cabbage head is burrowed into by the larva of the cabbage moth. Big green caterpillars feed on the tomato, and grape vines. A moth makes wormy apples and pears, but the curculio, a weevil beetle, punctures the skins of plums, cherries and peaches, and pushes an egg down to the stone. The currant worm strips the bush fruits of leaves. The slug of the saw fly destroys roses, and little, green, plant-lice, or aphides, suck the juices of rose bushes, fruit trees and hop vines. Cotton plants have three enemies—the cotton-boll weevil, the cotton worm, hatched from a moth egg, and the cotton stainer, a little red beetle. The chief enemy of corn is the cut worm. The army worm marches from field to field, millions strong, destroying grasslands. Grasshoppers come in clouds and leave bare fields behind them. On the bark of fruit trees a leech of an insect sucks unseen, under the black speck disc of the San Josť scale. The tree dies and the pest spreads through an orchard. The tent caterpillars often take entire limbs of fruit and shade trees. They weave a cob-web tent over a big colony of squirming leaf-eaters.
Hessian Fly which causes great damage to wheat.
Cotton-boll weevil; first figure showing insect at rest and second showing wing-covers lifted and wings extended for flight.
The number of species, or kinds of insects is far, far beyond all other living creatures put together. Some scientists say there may be a million species. They all lay countless eggs. One scientist says that a young cherry tree may have ten million plant-lice on it. In one year the codling moth has put worms into ten million dollars worth of apples, and the Hessian fly has destroyed one hundred million dollars worth of wheat in our country. All the insect pests put together cause a loss on our farm crops, orchard fruits and garden products of five hundred million dollars in some years.
Isn't it a wonder they leave anything at all for human beings and the higher animals to eat? Farmers and gardeners fight these enemies all the time. They spray plants and trees with poisons. They plow land in the fall, to turn up buried cocoons to the frost. They plant trap strips to catch the larva, and burn the strips. In gardens they pick off grubs and caterpillars by hand. They cut down trees and limbs and burn them. All the year around these enemies, too small, often, to be seen, too high to be reached, too hidden in the earth, in the fruits, the bark, the hearts and roots of plants, to be found, are fought. But all that human beings can do, is to keep them in check—sometimes. And sometimes men can only look on, quite helpless, and see fields laid waste. Don't you think farmers must often feel as Gulliver did, when he was bound by those swarms of five or six inch high Lilliputians?
If men had no help in fighting these billions of enemies they would lose the battle. But these greedy little creatures have enemies of their own, that live among them and prey upon them. These enemies of the insects are our friends. Do you know any of them?
Birds? Oh, yes, of course, all the song birds. We will tell you about our bird friends in another story. But there are some useful insects, too, that live on their kind, and a few other humble creatures that you may think of as pests. Perhaps, not knowing, you may have killed some of them. You ought to know all these friends so you can protect them, for we need all the help we can get in growing useful plants and animals. To help you understand just how powerful and destructive these insect enemies of ours are, turn back in this book to the names of some of them. See Insects, Caterpillars, Butterfly, Beetle, Fly, Weevil, Nature Study, Aphides, Army-Worm, Codlin Moth, Cotton-boll Weevil, Canker Worm, Chinch Bug, Hessian Fly, Grasshopper, Locust, Slug, Potato Bug, "Friends in Feathers."
Nest Of Grasshoppers Underground.
Nest Of Beetles Underground.
The eggs of these insects laid on the ground, hatch out into larvae or grubs which burrow in the ground, and when developed the insects crawl to the surface.