Deep culture of corn is not advisable. The roots in their early stages of growth are shallow feeders and spread widely only a few inches below the surface. The cultivation that destroys or disturbs the roots injures the plants and lessens the yield. We cultivate because of the three reasons given above, and not to stir the soil about the roots or to loosen it there.
3. Because "tillage is manure." Constant stirring of the soil allows the air to circulate in it, provides a more effective mulch, and helps to change unavailable plant food into the form that plants use.
Corn is a crop that needs constant cultivation, and during the growing season the soil should be stirred at least four times. This cultivation is for three reasons:
1. To destroy weeds that would take plant food and water.
2. To provide a mulch of dry soil so as to prevent the evaporation of moisture. The action of this mulch has already been explained.
The seed for this crop should be selected according to the plan suggested in
The most economical method of planting is by means of the horse planter, which, according to its adjustment, plants regularly in hills or in drills. A few days after planting, the cornfield should be harrowed with a fine-tooth harrow to loosen the top soil and to kill the grass and the weed seeds that are germinating at the surface. When the corn plants are from a half inch to an inch high, the harrow may again be used. A little work before the weeds sprout will save many days of labor during the rest of the season, and increase the yield.
When manure is not available, commercial fertilizers will often prove profitable on poor lands. Careful trials will best determine how much fertilizer to an acre is necessary, and what kinds are to be used. A little study and experimenting on the farmer's part will soon enable him to find out both the kind and the amount of fertilizer that is best suited to his land.
A soil rich in either decaying animal or vegetable matter, loose, warm, and moist but not wet, will produce a better crop of corn than any other. Corn soil should always be well tilled and cultivated.
The proper time to begin the cultivation of corn is before it is planted. Plow well. A shallow, worn-out soil should not be used for corn, but for cowpeas or rye. After thorough plowing, the harrow—either the disk or spring-tooth—should be used to destroy all clods and leave the surface mellow and fine. The best results will be obtained by turning under a clover sod that has been manured from the savings of the barnyard.
When the white man came to this country he found the Indians using corn; for this reason, in addition to its name maize, it is called Indian corn. Before that time the civilized world did not know that there was such a crop. The increase in the yield and the extension of the acres planted in this strictly American crop have kept pace with the rapid and wonderful growth of our country. Corn is king of the cereals and the most important crop of American agriculture. It grows in almost every section of America. There is hardly any limit to the uses to which its grain and its stalks are now put. Animals of many kinds are fed on rations into which it enters. Its grains in some form furnish food to more people than does any other crop except possibly rice. Its stalk and its cob are manufactured into many different and useful articles.
EXERCISE
Let the pupils secure several heads of wheat and thresh each separately by hand. The grains should then be counted and their plumpness and size observed. The practical importance of this is obvious, for the larger the heads and the greater the number of grains, the larger the yield per acre. Let them plant some of the large and some of the small grains. A single test of this kind will show the importance of careful seed-selection.
The farmer is assisted always by a study of his crop and by a knowledge of how it grows. If he find the straw inferior and short, it means that the soil is deficient in nitrogen; but on the other hand, if the straw be luxuriant and the heads small and poorly filled, he may be sure that his soil contains too little phosphoric acid and potash.
It should be remembered always in buying fertilizers for wheat that whenever wheat follows cowpeas or clover or other legumes there is seldom need of using nitrogen in the fertilizer; the tubercles on the pea or clover roots will furnish that. Hence, as a rule, only potash and phosphoric acid will have to be purchased as plant food.
In many parts of the country, because not enough live stock is raised, there is often too little manure to apply to the wheat land. Where this is the case commercial fertilizers must be used. Since soils differ greatly, it is impossible to suggest a fertilizer adapted to all soils. The elements usually lacking in wheat soils are nitrogen, phosphoric acid, and potash. The land may be lacking in one of these plant foods or in all; in either case a maximum crop cannot possibly be raised. The section on manuring the soil will be helpful to the wheat-grower.
There are a great many varieties of wheat: some are bearded, others are smooth; some are winter and others are spring varieties. The smooth-headed varieties are most agreeable to handle during harvest and at threshing-time. Some of the bearded varieties, however, do so well in some soils and climates that it is desirable to continue growing them, though they are less agreeable to handle. No matter what variety you are accustomed to raise, it may be improved by careful seed-selection.
The seed-drill is the best implement for planting wheat. It distributes the grains evenly over the whole field and leaves the mellow soil in a condition to catch what snow may fall and secure what protection it affords.
One may secure a good seed-bed after cotton and corn as well as after cowpeas and other legumes. They are summer-cultivated crops, and the clean culture that has been given them renders the surface soil mellow and the undersoil firm and compact. They are not so good, however, as cowpeas, since they add no atmospheric nitrogen to the soil, as all leguminous crops do.
From one to two inches is the most satisfactory depth for planting wheat. The largest number of seeds comes up when planted at this depth. A mellow soil is very helpful to good coming up and provides a most comfortable home for the roots of the plant. A compact soil below makes a moist undersoil; and this is desirable, for the soil water is needed to dissolve plant food and to carry it up through the plant, where it is used in building tissue.
Clay soils that are hard and lifeless can be made valuable for wheat-production by covering the surface with manure, by good tillage, and by a thorough system of crop-rotation. Cowpeas and other legumes make a most valuable crop to precede wheat, for in growing they add atmospheric nitrogen to the soil, and their roots loosen the root-bed, thereby admitting a free circulation of air and adding humus to the soil. Moreover, the legumes leave the soil with its grains fairly close packed, and this is a help in wheat growing.
This crop ranks third in value in the United States. It grows in cool, in temperate, and in warm climates, and in many kinds of soil. It does best in clay loam, and worst in sandy soils. Clogged and water-soaked land will not grow wheat with profit to the farmer; for this reason, where good wheat-production is desired the soil must be well drained and in good physical condition—that is, the soil must be open, crumbly, and mellow.
Wheat has been cultivated from earliest times. It was a chief crop in Egypt and Palestine, and still holds its importance in the temperate portions of Europe, Asia, Africa, Australia, and America.
In tobacco culture it is necessary to pinch off the "buttons" and to cut off the tops of the main stalk, else much nourishment that should go to the leaves will be given to the seeds. The suckers must also be cut off for the same reason.
The proper time for harvesting is not easily fixed; one becomes skillful in this work only through experience in the field. Briefly, we may say that tobacco is ready to be cut when the leaves on being held up to the sun show a light or golden color, when they are sticky to the touch, and when they break easily on being bent. Plants that are overripe are inferior to those that are cut early.
The operations included in cutting, housing, drying, shipping, sweating, and packing require skill and practice.
The plants, when ready, are transplanted in very much the same way as cabbages and tomatoes. The transplanting was formerly done by hand, but an effective machine is now widely used. The rows should be from three to three and a half feet apart, and the plants in the rows about two or three feet apart. If the plants are set so that the plow and cultivator can be run with the rows and also across the rows, they can be more economically worked. Tobacco, like corn, requires shallow cultivation. Of course the plants should be worked often enough to give clean culture and to provide a soil mulch for saving moisture.
The time required for sprouting is from two to three weeks. The plants ought to be ready for transplanting in from four to six weeks. Weeds and grass should of course be kept out of the seed-bed.
Deep plowing—from nine to thirteen inches—is also a necessity in preparing the land, for tobacco roots go deep into the soil. After this deep plowing, harrow until the soil is thoroughly pulverized and is as fine and mellow as that of the flower-garden.
Unlike most other farm crops the tobacco plant must be started first in a seed-bed. To prepare a tobacco bed the almost universal custom has been to proceed as follows. Carefully select a protected spot. Over this spot pile brushwood and then burn it. The soil will be left dry, and all the weed seeds will be killed. The bed is then carefully raked and smoothed and planted. Some farmers are now preparing their beds without burning. A tablespoonful of seed will sow a patch twenty-five feet square. A cheap cloth cover is put over the bed. If the seeds come up well, a patch of this size ought to furnish transplants for five or six acres. In sowing, it is not wise to cover the seed deeply. A light raking in or an even rolling of the ground is all that is needed.
The soil in which tobacco thrives best is one which has the following qualities: dryness, warmth, richness, depth, and sandiness.
Commercial fertilizers also are almost a necessity; for, as tobacco land is limited in area, the same land must be often planted in tobacco. Hence even a fresh, rich soil that did not at first require fertilizing soon becomes exhausted, and, after the land has been robbed of its plant food by crop after crop of tobacco, frequent application of fertilizers and other manures becomes necessary. However, even tobacco growers should rotate their crops as much as possible.
The tobacco plant connects Indian agriculture with our own. It has always been a source of great profit to our people. In the early colonial days tobacco was almost the only money crop. Many rich men came to America in those days merely to raise tobacco.
Although tobacco will grow in almost any climate, the leaves, which, as most of you know, are the salable part of the plant, get their desirable or undesirable qualities very largely from the soil and from the climate in which they grow.
First, to say nothing of the money made from the cattle, the large quantity of stable manure saved will largely reduce the amount of commercial fertilizer needed. The cotton-farmer cannot afford to neglect cattle-raising. The cattle sections of the country are likely to make the greatest progress in agriculture, because they have manure always on hand.
Second, the nitrogen-gathering crops, while helping to feed the stock, also reduce the fertilizer bills by supplying one of the costly elements of the fertilizer. The ordinary cotton fertilizer consists principally of nitrogen, of potash, and of phosphoric acid. Of these three, by far the most costly is nitrogen. Now peas, beans, clover, and peanuts will leave enough nitrogen in the soil for cotton, so that if they are raised, it is necessary to buy only phosphoric acid and sometimes potash.
Relation of Stock to the Cotton Crop. On many farms much of the money for which the cotton is sold in the fall has to go to pay for the commercial fertilizer used in growing the crop. Should not this fact suggest efforts to raise just as good crops without having to buy so much fertilizer? Is there any way by which this can be done? The following suggestions may be helpful. Raise enough stock to use all the cotton seed grown on the farm. To go with the food made from the cotton seed, grow on the farm pea-vine hay, clover, alfalfa, and other such nitrogen-gathering crops. This can be done at small cost. What will be the result?
The stable manure, if that is used, should be broadcasted over the fields at the rate of six to ten tons an acre. If commercial fertilizers are used, it may be best to make two applications. To give the young plants a good start, apply a portion of the fertilizer in the drill just before planting. Then when the first blooms appear, put the remainder of the fertilizer in drills near the plants but not too close. Many good cotton-growers, however, apply all the fertilizer at one time.
The number of times the crop has to be worked depends on the soil and the season. If the soil is dry and porous, cultivate as often as possible, especially after each rain. Never allow a crust to form after a rain; the roots of plants must have air. Cultivation after each rain forms a dry mulch on the top of the soil and thus prevents rapid evaporation of moisture.
If the fiber (the lint) only is removed from the land on which cotton is grown, cotton is the least exhaustive of the great crops grown in the United States. According to some recent experiments an average crop of cotton removes in the lint only 2.75 pounds of nitrogen, phosphoric acid, potash, lime, and magnesia per acre, while a crop of ten bushels of wheat per acre removes 32.36 pounds of the same elements of plant food. Inasmuch as this crop takes so little plant food from the soil, the cotton-farmer has no excuse for allowing his land to decrease in productiveness. Two things will keep his land in bounteous harvest condition: first, let him return the seeds in some form to the land, or, what is better, feed the ground seeds to cattle, make a profit from the cattle, and return manure to the land in place of the seeds; second, at the last working, let him sow some crop like crimson clover or rye in the cotton rows to protect the soil during the winter and to leave humus in the ground for the spring.
The cheapest way of cultivating a crop is to prevent grass and weeds from rooting, not to wait to destroy them after they are well rooted. To do this, it is well to run the two-horse smoothing-harrow over the land, across the rows, a few days after the young plants are up. Repeat the harrowing in six or eight days. In addition to destroying the young grass and weeds, this harrowing also removes many of the young cotton plants and thereby saves much hoeing at "chopping-out" time. When the plants are about two inches high they are "chopped out" to secure an evenly distributed stand. It has been the custom to leave two stalks to a hill, but many growers are now leaving only one.
The rows should be from three to four feet apart. The width depends upon the richness of the soil. On rich land the rows should be at least four feet apart. This width allows the luxuriant plant to branch and fruit well. On poorer lands the distance of the rows should not be so great. The distribution of the seed in the row is of course most cheaply done by the planter. As a rule it is best not to ridge the land for the seed. Flat culture saves moisture and often prevents damage to the roots. In some sections, however, where the land is flat and full of water, ridging seems necessary if the land cannot be drained.
In preparing for cotton-planting, first disk the land thoroughly, then break with a heavy plow and harrow until a fine and mellow seed-bed is formed. Do not spare the harrow at this time. It destroys many a weed that, if allowed to grow, would have to be cut by costly hoeing. Thorough work before planting saves much expensive work in the later days of the crop. Moreover, no man can afford to allow his plant food and moisture to go to nourish weeds, even for a short time.
On some cotton farms it is the practice to break the land in winter or early spring and then let it lie naked until planting-time. This is not a good practice. The winter rains wash more plant food out of unprotected soil than a single crop would use. It would be better, in the late summer or fall, to plant crimson clover or some other protective and enriching crop on land that is to be planted in cotton in the spring. This crop, in addition to keeping the land from being injuriously washed, would greatly help the coming cotton crop by leaving the soil full of vegetable matter.
The cotton plant is nourished by a tap-root that will seek food as deeply as loose earth will permit the root to penetrate; hence, in preparing land for this crop the first plowing should be done at least with a two-horse plow and should be deep and thorough. This deep plowing not only allows the tap-root to penetrate, but it also admits a circulation of air.
Many attempts have been made and are still being made to increase the length of the staple of the upland types. The methods used are as follows: selection of seed having a long fiber; special cultivation and fertilization; crossing the short-stapled cotton on the long-stapled cotton. This last process, as already explained, is called hybridizing. Many of these attempts have succeeded, and there are now a large number of varieties which excel the older varieties in profitable yield. The new varieties are each year being more widely grown. Every farmer should study the new types and select the one that will best suit his land. The new types have been developed under the best tillage. Therefore if a farmer would keep the new type as good as it was when he began to grow it, he must give it the same good tillage, and practice seed-selection.
There are a great many varieties of cotton. Two types are mainly grown by the practical American farmer. These are the short-stapled, upland variety most commonly grown in all the Southern states, and the beautiful, long-stapled, black-seeded sea-island type that grows upon the islands and a portion of the mainland of Georgia, South Carolina, and Florida. The air of the coast seems necessary for the production of this latter variety. The seeds of the sea-island cotton are small, smooth, and black. They are so smooth and stick so loosely to the lint that they are separated from it by roller-gins instead of by saw-gins. When these seeds are planted away from the soil and air of their ocean home, the plant does not thrive.
In America the Southern states from Virginia to Texas have these climatic qualities, and it is in these states that the cotton industry has been developed until it is one of the giant industries of the world. This development has been very rapid. As late as 1736 the cotton plant was grown as an ornamental flowering plant in many front yards; in 1911, 16,250,276 bales of cotton were grown in the South. In recent years the soil and climate of lower California and parts of Arizona and New Mexico have been found well adapted to cotton.
Cotton was originally a tropical plant, but, strange to say, it seems to thrive best in temperate zones. The cotton plant does best, according to Newman, in climates which have (1) six months of freedom from frost; (2) a moderate, well-distributed rainfall during the plant's growing period; and (3) abundant sunshine and little rain during the plant's maturing period.
In the cotton belt almost any well-drained soil will produce cotton. The following kinds of soil are admirably suited to this plant: red and gray loams with good clay subsoil; sandy soils over clay and sandstone and limestone; rich, well-drained bottom-lands. The safest soils are medium loams. Cotton land must always be well drained.
Although cotton was cultivated on the Eastern continent before America was discovered, this crop owes its present kingly place in the business world to the zeal and intelligence of its American growers. So great an influence does it wield in modern industrial life that it is often called King Cotton. Thousands upon thousands of people scan the newspapers each day to see what price its staple is bringing. From its bounty a vast army of toilers, who plant its seed, who pick its bolls, who gin its staple, who spin and weave its lint, who grind its seed, who refine its oil, draw daily bread. Does not its proper production deserve the best thought that can be given it?
The figures below give the average amount of money made annually an acre on our chief crops:
Flowers and plants, $1911; nursery products, $261; onions, $140; sugar cane, $55; small fruits, $110; hops, $175; vegetables, $78; tobacco, $80; sweet potatoes, $55; hemp, $53; potatoes, $78; sugar beets, $54; sorghum cane, $22; cotton, $22; orchard fruits, $110; peanuts, $21; flax-seed, $14; cereals, $14; hay and forage, $11; castor beans, $6 (United States Census Report).
Success in growing any crop is largely due to the suitableness of soil and climate to that crop. When the planter selects both the most suitable soil and the most suitable climate for each crop, he gets not only the most bountiful yield from the crop but, in addition, he gets the most desirable quality of product. A little careful observation and study soon teach what kinds of soil produce crops of the highest excellence. This learned, the planter is able to grow in each field the several crops best adapted to that special type of soil. Thus we have tobacco soils, trucking soils, wheat and corn soils. Dairying can be most profitably followed in sections where crops like cowpeas, clover, alfalfa, and corn are peculiarly at home. No one should try to grow a new crop in his section until he has found out whether the crop which he wants to grow is adapted to his soil and his climate.
Every crop of the farm has been changed and improved in many ways since its forefathers were wild plants. Those plants that best serve the needs of the farmer and of farm animals have undergone the most changes and have received also the greatest care and attention in their production and improvement.
While we have many different kinds of farm crops, the cultivated soil of the world is occupied by a very few. In our country the crop that is most valuable and that occupies the greatest land area is generally known as the grass crop. Included in the general term "grass crop" are the grasses and clovers that are used for pasturage as well as for hay. Next to grass in value come the great cereal, corn, and the most important fiber crop, cotton, closely followed by the great bread crop, wheat. Oats rank fifth in value, potatoes sixth, and tobacco seventh. (These figures are for 1913.)
In adopting the first method mentioned the cotton growers have found that by the careful selection of seed, by early planting, by a free use of fertilizers containing phosphoric acid, and by frequent plowing, they can mature a crop about thirty days earlier than they usually do. In this way a good crop can be harvested before the weevils are ready to be most destructive.
The places best adapted for a winter home for the weevil are trash piles, rubbish, driftwood, rotten wood, weeds, moss on trees, etc. A further help, therefore, in destroying the weevil is to cut down and burn all cotton-stalks as soon as the cotton is harvested.
This destroys countless numbers of larvæ and pupæ in the bolls and greatly reduces the number of weevils. In addition, all cornstalks, all trash, all large clumps of grass in neighboring fields, should be burned, so as to destroy these winter homes of the weevil. Also avoid planting cotton near trees. The bark, moss, and fallen leaves of the tree furnish a winter shelter for the weevils.
A third help in destroying the weevil is to rotate crops. If cotton does not follow cotton, the weevil has nothing on which to feed the second year.
This weevil is proving very hard to destroy. At present there seem but few ways to fight it. One is to grow cotton that will mature too early for the weevils to do it much harm. A second is to kill as many weevils as possible by burning the homes that shelter them in winter.
 Fig. 178. A Cotton Boll with Feeding-Holes of Weevil, and Bearing Three Specimens of the Insect |
 Fig. 179. The Mexican Cotton-Boll Weevil, showing Structure |
In from one to two weeks the grub or larva becomes fully grown and, without changing its home, is transformed into the pupa state. Then in about a week more the pupæ come out as adult weevils and attack the bolls. They puncture them with their snouts and lay their eggs in the bolls. The young grubs, this time hatching out in the boll, remain there until grown, when they emerge through holes that they make. These holes allow dampness to enter and destroy the bolls. This life-round continues until cold weather drives the insects to their winter quarters. By that time they have increased so rapidly that there is often one for every boll in the field.
In the spring, generally about the time cotton begins to form "squares," the weevils shake off their long winter sleep and enter the cotton fields with appetites as sharp as razors. Then shortly the females begin to lay eggs. At first these eggs are laid only in the squares, and generally only one to the square. The young grub hatches from these eggs in two or three days. The newly hatched grub eats the inside of the square, and the square soon falls to the ground. Entire fields may at times be seen without a single square on the plants. Of course no fruit can be formed without squares.
The grown weevils try to outlive the cold of winter by hiding snugly away under grass clumps, cotton-stalks, rubbish, or under the bark of trees. Sometimes they go down into holes in the ground. A comfortable shelter is often found in the forests near the cotton fields, especially in the moss on the trees. The weevils can stand a good deal of cold, but fortunately many are killed by winter weather. Moreover birds destroy many; hence by spring the last year's crop is very greatly diminished.
This weevil is a small gray or reddish-brown snout-beetle hardly over a quarter of an inch in length. In proportion to its length it has a long beak. It belongs to a family of beetles which breed in pods, in seeds, and in stalks of plants. It is a greedy eater, but feeds only on the cotton plant.
 Fig. 173. Eggs among the Anthers of a Square at the Point Indicated by the Arrow |
 Fig. 174. Cross Section showing Anthers of a Square with Egg of Weevil, and showing the Hole where the Egg was deposited Greatly enlarged |
So far as known, the cotton-boll weevil, an insect which is a native of
the tropics, crossed the Rio Grande River into Texas in 1891 and 1892.
It settled in the cotton fields around Brownsville. Since then it has
widened its destructive area until now it has invaded the whole
territory shown by the map on page 177.
EXERCISE
How does the squash bug resemble the plant louse? Is this a true bug? Gather some eggs and watch the development of the insects in a breeding-cage. Estimate the damage done to some crops by the flea-beetle. What is the best method of prevention?
Do you know the large moth that is the mother of the tobacco worm? You may often see her visiting the blossoms of the Jimson weed. Some tobacco-growers cultivate a few of these weeds in a tobacco field. In the blossom they place a little cobalt or "fly-stone" and sirup. When the tobacco-worm moth visits this flower and sips the poisoned nectar, she will of course lay no more troublesome eggs.
In dealing with plants, as with human beings, the great object should be not the cure but the prevention of disease. If disease can be prevented, it is far too costly to wait for it to develop and then to attempt its cure. Men of science are studying the new forms of diseases and new insects as fast as they appear. These men are finding ways of fighting old and new enemies. Young people who expect to farm should early learn to follow their advice.
The Potato Beetle; Tobacco Worm. The potato beetle, tobacco worm, etc., are too well known to need description. Suffice it to say that no good farmer will neglect to protect his crop from any pest that threatens it.
The increase, owing to various causes, of insects, of fungi, of bacterial diseases, makes a study of these pests, of their origin, and of their prevention a necessary part of a successful farmer's training. Tillage alone will no longer render orchard, vineyard, and garden fruitful. Protection from every form of plant enemies must be added to tillage.
Treatment. Burn all stubble and trash during July and August. If the fly is very bad, it is well to leave the stubble unusually high to insure a rapid spread of the fire. Burn refuse from the threshing-machine, since this often harbors many larvæ or pupæ. Follow the burning by deep plowing, because the burning cannot reach the insects that are in the base of the plants. Delay the fall planting until time for heavy frosts.
The Hessian Fly. The Hessian fly does more damage to the wheat crop than all other insects combined, and probably ranks next to the chinch bug as the second worst insect enemy of the farmer. It was probably introduced into this country by the Hessian troops in the War of the Revolution.
In autumn the insect lays its eggs in the leaves of the wheat. These hatch into the larvæ, which move down into the crown of the plant, where they pass the winter. There they cause on the plant a slight gall formation, which injures or kills the plant. In the spring adult flies emerge and lay eggs. The larvæ that hatch feed in the lower joints of the growing wheat and prevent its proper growth. These larvæ pupate and remain as pupæ in the wheat stubble during the summer. The fall brood of flies appears shortly before the first heavy frost.
The Weevil. The weevil is commonly found among seeds. Its attacks are serious, but the insect may easily be destroyed.
Treatment. Put the infected seeds in an air-tight box or bin, placing on the top of the pile a dish containing carbon disulphide, a tablespoonful to a bushel of seeds. The fumes of this substance are heavy and will pass through the mass of seeds below and kill all the weevils and other animals there. The bin should be closely covered with canvas or heavy cloth to prevent the fumes from being carried away by the air. Let the seeds remain thus from two to five days. Repeat the treatment if any weevils are found alive. Fumigate when the temperature is 70° Fahrenheit or above. In cold weather or in a loose bin the treatment is not successful. Caution: Do not approach the bin with a light, since the fumes of the chemical used are highly inflammable.
The Flea-Beetle. The flea-beetle inflicts much damage on the potato, tomato, eggplant, and other garden plants. The accompanying figure shows the common striped flea-beetle which lives on the tomato. The larva of this beetle lives inside of the leaves, mining its way through the leaf in a real tunnel. Any substance disagreeable to the beetle, such as plaster, soot, ashes, or tobacco, will repel its attacks on the garden crops.
Treatment. About the only practicable remedy is to pick these insects by hand. We can, however, protect our young plants by small nettings and thus tide them over the most dangerous period of their lives. These bugs greatly prefer the squash as food. You can therefore diminish their attack on your melons, cucumbers, etc. by planting among the melons an occasional squash plant as a "trap plant." Hand picking will be easier on a few trap plants than over the whole field. A small board or large leaf laid beside the young plant often furnishes night shelter for the bugs. The bugs collected under the board may easily be killed every morning.
The Squash Bug. The squash bug does its greatest damage to young plants. To such its attack is often fatal. On larger plants single leaves may die. This insect is a serious enemy to a crop and is particularly difficult to get rid of, since it belongs to the class of sucking insects, not to the biting insects. For this reason poisons are useless.
Treatment. These are sucking insects. Poisons therefore do not avail. They may be killed by spraying with kerosene emulsion or a strong soap solution or with tobacco water. Lice on cabbages are easily killed by a mixture of one pound of lye soap in four gallons of warm water.
The plant louse gives off a sweetish fluid of which some ants are very fond. You may often see the ants stroking these lice to induce them to give off a freer flow of the "honey dew." This is really a method of milking. However friendly and useful these "cows" may be to the ant, they are enemies to man in destroying so many of his plants.
The Plant Louse. The plant louse is very small, but it multiplies with very great rapidity. During the summer the young are born alive, and it is only toward fall that eggs are laid. The individuals that hatch from eggs are generally wingless females, and their young, born alive, are both winged and wingless. The winged forms fly to other plants and start new colonies. Plant lice mature in from eight to fourteen days.
Treatment. Unfortunately we cannot prevent all of the damage done by chinch bugs, but we can diminish it somewhat by good clean agriculture. Destroy the winter homes of the insect by burning dry grass, leaves, and rubbish in fields and fence rows. Although the insect has wings, it seldom or never uses them, usually traveling on foot; therefore a deep furrow around the field to be protected will hinder or stop the progress of an invasion. The bugs fall into the bottom of the furrow, and may there be killed by dragging a log up and down the furrow. Write to the Division of Entomology, Washington, for bulletins on the chinch bug. Other methods of prevention are to be found in these bulletins.
Treatment. Birds aid in the destruction of this pest. Paris green mixed with air-slaked lime will also kill many larvæ. After the cabbage has headed, it is very difficult to destroy the worm, but pyrethrum insect powder used freely is helpful.
The Chinch Bug. The chinch bug, attacking as it does such important crops as wheat, corn, and grasses, is a well-known pest. It probably causes more money loss than any other garden or field enemy. In Orange county, North Carolina, farmers were once obliged to suspend wheat-growing for two years on account of the chinch bug. In one year in the state of Illinois this bug caused a loss of four million dollars.
The Cabbage Worm. The cabbage worm of the early spring garden is a familiar object, but you may not know that the innocent-looking little white butterflies hovering about the cabbage patch are laying eggs which are soon to hatch and make the dreaded cabbage worms. In Fig. 164 a and b show the common cabbage butterfly, c shows several examples of the caterpillar, and d shows the pupa case. In the pupa stage the insects pass the winter among the remains of old plants or in near-by fences or in weeds or bushes. Cleaning up and burning all trash will destroy many pupæ and thus prevent many cabbage worms. In Fig. 164 e and f show the moth and zebra caterpillar; g represents a moth which is the parent of the small green worm shown at h. This worm is a common foe of the cabbage plant.
Watch the curculio lay her eggs in the plums, peaches, or cherries. What per cent of fruit is thus injured? Estimate the damage. Let the school offer a prize for the greatest number of tent-caterpillar eggs. Watch such trees as the apple, the wild and the cultivated cherry, the oak, and many others.
Make a collection of insects injurious to orchard fruits, showing in each case the whole life history of the insect, that is, eggs, larva, pupa, and the mature insects.
EXERCISE
How many apples per hundred do you find injured by the codling moth? Collect some cocoons from a pear or an apple tree in winter, place in a breeding-cage, and watch for the moths that come out. Do you ever see the woodpecker hunting for these same cocoons? Can you find cocoons that have been emptied by this bird? Estimate how many he considers a day's ration. How many apples does he thus save?
Treatment. If there are only a few trees in the orchard, digging the worms out with a knife is the best way of destroying them. You can know of the borer's presence by the exuding gum often seen on the tree-trunk. If you pile earth around the roots early in the spring and remove it in the late fall, the winter freezing and thawing will kill many of the larvæ.
The Peach-Tree Borer. In Fig. 161 you see the effect of the peach-tree borer's activity. These borers often girdle and thereby kill a tree. Fig. 162 shows the adult state of the insect. The eggs are laid on peach or plum trees near the ground. As soon as the larva emerges, it bores into the bark and remains there for months, passing through the pupa stage before it comes out to lay eggs for another generation.
The Twig Girdler. The twig girdler lays her eggs in the twigs of pear, pecan, apple, and other trees. It is necessary that the larvæ develop in dead wood. This the mother provides by girdling the twig so deeply that it will die and fall to the ground.
Treatment. Since the larvæ spend the winter in the dead twigs, burn these twigs in autumn or early spring and thus destroy the pest.
Treatment. There are three principal methods, (1) Destroy the eggs. The egg masses are readily seen in winter and may easily be collected and burned by boys. The chickadee eats great quantities of these eggs. (2) With torches burn the nests at dusk when all the worms are within. You must be very careful in burning or you will harm the young branches with their tender bark. (3) Encourage the residence of birds. Urge your neighbors to make war on the larvæ, too, since the pest spreads rapidly from farm to farm. Regularly sprayed orchards are rarely troubled by this pest.
Encourage the chickadee and all other birds, except the English sparrow, to stay in your orchard. This is easily done by feeding and protecting them in their times of need.
The Apple-Tree Tent Caterpillar. The apple-tree tent caterpillar is a larva so well known that you only need to be told how to guard against it. The mother of this caterpillar is a reddish moth. This insect passes the winter in the egg state securely fastened on the twigs as shown in Fig. 159, a.
Treatment. The inability of the female to fly gives us an easy way to prevent the larval offspring from getting to the foliage of our trees, for we know that the only highway open to her or her larvæ leads up the trunk. We must obstruct this highway so that no crawling creature may pass. This is readily done by smoothing the bark and fitting close to it a band of paper, and making sure that it is tight enough to prevent anything from crawling underneath. Then smear over the paper something so sticky that any moth or larva that attempts to pass will be entangled. Printer's ink will do very well, or you can buy either dendrolene or tanglefoot.
Nearly all the common birds feed freely upon the cankerworm, and benefit the orchard in so doing. The chickadee is perhaps the most useful. A recent writer is very positive that each chickadee will devour on an average thirty female cankerworm moths a day; and that if the average number of eggs laid by each female is one hundred and eighty-five, one chickadee would thus destroy in one day five thousand five hundred and fifty eggs, and, in the twenty-five days in which the cankerworm moths crawl up the tree, would rid the orchard of one hundred and thirty-eight thousand seven hundred and fifty. These birds also eat immense numbers of cankerworm eggs before they hatch into worms.
In early summer the larvæ burrow within the earth and pupate there; later they emerge as adults (Fig. 157, d and e). You observe the peculiar difference between the wingless female, d, and the winged male, e. It is the habit of this wingless female to crawl up the trunk of some near-by tree in order to deposit her eggs upon the twigs. These eggs (shown at a and b) hatch into the greedy larvæ that do so much damage to our orchards.
In early summer the larvæ burrow within the earth and pupate there; later they emerge as adults (Fig. 157, d and e). You observe the peculiar difference between the wingless female, d, and the winged male, e. It is the habit of this wingless female to crawl up the trunk of some near-by tree in order to deposit her eggs upon the twigs. These eggs (shown at a and b) hatch into the greedy larvæ that do so much damage to our orchards.
The Cankerworm. The cankerworm is the larva of a moth. Because of its peculiar mode of crawling, by looping its body, it is often called the looping worm or measuring worm (Fig. 157, c). These worms are such greedy eaters that in a short time they can so cut the leaves of an orchard as to give it a scorched appearance. Such an attack practically destroys the crop and does lasting injury to the tree. The worms are green or brown and are striped lengthwise. If the tree is jarred, the worm has a peculiar habit of dropping toward the ground on a silken thread of its own making (Fig. 156).
Treatment. The Clinton grape is most liable to injury from this pest. Hence it is better to grow other more resistant kinds. Sometimes the lice attack the roots of the grape vines. In many sections where irrigation is practiced the grape rows are flooded when the lice are thickest. The water drowns the lice and does no harm to the vines.
Fowls in the orchard do good by capturing the larvæ before they can burrow, while hogs will destroy the fallen fruit before the larvæ can escape.
The Grape Phylloxera. The grape phylloxera is a serious pest. You have no doubt seen its galls upon the grape leaf. These galls are caused by a small louse, the phylloxera. Each gall contains a female, which soon fills the gall with eggs. These hatch into more females, which emerge and form new galls, and so the phylloxera spreads (see Fig. 155).
Treatment. Burn orchard trash which may serve as winter quarters. Spraying with arsenate of lead, using two pounds of the mixture to fifty gallons of water, is the only successful treatment for the curculio. For plums and peaches, spray first when the fruit is free from the calyx caps, or dried flower-buds. Repeat the spraying two weeks later. For late peaches spray a third time two weeks after the second spraying. This poisonous spray will kill the beetles while they are feeding or cutting holes in which to lay their eggs.
The Plum Curculio. The plum curculio, sometimes called the plum weevil, is a little creature about one fifth of an inch long. In spite of its small size the curculio does, if neglected, great damage to our fruit crop. It injures peaches, plums, and cherries by stinging the fruit as soon as it is formed. The word "stinging" when applied to insects—- and this case is no exception—means piercing the object with the egg-layer (ovipositor) and depositing the egg. Some insects occasionally use the ovipositor merely for defense. The curculio has an especially interesting method of laying her egg. First she digs a hole, in which she places the egg and pushes it well down. Then with her snout she makes a crescent-shaped cut in the skin of the plum, around the egg. This mark is shown in Fig. 154. As this peculiar cut is followed by a flow of gum, you will always be able to recognize the work of the curculio. Having finished with one plum, this industrious worker makes her way to other plums until her eggs are all laid. The maggotlike larva soon hatches, burrows through the fruit, and causes it to drop before ripening. The larva then enters the ground to a depth of several inches. There it becomes a pupa, and later, as a mature beetle, emerges and winters in cracks and crevices.
It is best to use lime-sulphur mixture or the Bordeaux mixture with arsenate of lead for a spray. Thus one spraying serves against both fungi and insects.
Treatment. Destroy orchard trash which may serve as a winter home. Scrape all loose bark from the tree. Spray the tree with arsenate of lead as soon as the flowers fall. A former method of fighting this pest was as follows: bands of burlap four inches wide tied around the tree furnished a hiding-place for larvæ that came from windfalls or crawled from wormy apples on the tree. The larvæ caught under the bands were killed every five or six days. We know now, however, that a thorough spraying just after the blossoms fall kills the worms and renders the bands unnecessary. Furthermore, spraying prevents wormy apples, while banding does not. Follow the first spraying by a second two weeks later.
There are several ways of making the lime-sulphur mixture. It is generally best to buy a prepared mixture from some trustworthy dealer. If you find the scale on your trees, write to your state experiment station for directions for combating it.
The Codling Moth. The codling moth attacks the apple and often causes a loss of from twenty-five to seventy-five per cent of the crop. In the state of New York this insect is causing an annual loss of about three million dollars. The effect it has on the fruit is most clearly seen in Fig. 152. The moth lays its egg upon the young leaves just after the falling of the blossom. She flies on from apple to apple, depositing an egg each time until from fifty to seventy-five eggs are deposited. The larva, or "worm," soon hatches and eats its way into the apple. Many affected apples ripen too soon and drop as "windfalls." Others remain on the tree and become the common wormy apples so familiar to growers. The larva that emerges from the windfalls moves generally to a tree, crawls up the trunk, and spins its cocoon under a ridge in the bark. From the cocoon the moth comes ready to start a new generation. The last generation of the larvæ spends the winter in the cocoon.
The San Jose Scale. The San Jose scale is one of the most dreaded enemies of fruit trees. It is in fact an outlaw in many states. It is an unlawful act to sell fruit trees affected by it. Fig. 150 shows a view of a branch nearly covered with this pest. Although this scale is a very minute animal, yet so rapidly does it multiply that it is very dangerous to the tree. Never allow new trees to be brought into your orchard until you feel certain that they are free from the San Jose scale. If, however, it should in any way gain access to your orchard, you can prevent its spreading by thorough spraying with what is known as the lime-sulphur mixture. This mixture has long been used on the Pacific coast as a remedy for various scale insects. When it was first tried in other parts of the United States the results were not satisfactory and its use was abandoned. However, later experiments with it have proved that the mixture is thoroughly effective in killing this scale and that it is perfectly harmless to the trees. Until the lime-sulphur mixture proved to be successful the San Jose scale was a most dreaded nursery and orchard foe. It was even thought necessary to destroy infected trees. The lime-sulphur mixture and some other sulphur washes not only kill the San Jose scale but are also useful in reducing fungous injury.
 Fig. 150. San Jose Scale |
 Fig. 151. Single San Jose Scale Magnified |
