Zinc is a whitish metal. It is used in galvanizing iron to prevent its rusting. It is used also in the manufacture of white paint, which consumes about one ton out of every six tons mined. This, of course, is permanently lost, but the price and its value as a resource is much lower than lead. This takes more than half of the entire product. Theremainder of the output is about equally divided between brass and sheet zinc. All these uses are extremely necessary and it is believed that the production of zinc will rapidly increase for many years.
The United States is the largest producer, Germany ranks second. Large amounts are mined in Australia, and very large deposits, entirely undeveloped, are said to exist in Africa. In 1880, the United States produced 23,000 tons of zinc; in 1907, 280,000 tons. This indicates the rapid rate at which we are increasing our use of zinc.
If the same rate should continue, in 1920 we should be using 475,000 tons, or almost a billion pounds, and if zinc oxide should take the place of white lead in painting to the extent that now seems probable, the quantity would be still further increased.
Missouri is by far the heaviest producer of zinc, having a little more than half of the output. New Jersey ranks next, then Colorado, Wisconsin and Kansas. Some of the other western states each produce small amounts. Most of the pure zinc ore is mined at a depth of from one hundred and fifty to two hundred and fifty feet and occurs in sheets, but a large part of the ore is a by-product obtained from the reduction of other ores. In New Jersey the zinc alone is found in a single region, where it was estimated a few years ago that there were eightmillion tons, of which two and a half million tons have been mined since 1904. The zinc in Missouri, Wisconsin and Kansas is found alone or underlying lead deposits, while that of the western states is almost always found in limestone, and is mixed with silver, copper, lead, and, more rarely, gold. In these states there has been little attempt to discover zinc; in fact, ores containing zinc have been rather shunned because of the difficulty in extracting them.
It is thought that our resources of zinc, especially in the West, have just begun to be developed, and that the supply, even at the present rate of increase and at present prices, will last many years. However, with increasing use for the product, we can not be sure of supplies for more than a generation; and in view of the importance of zinc it becomes necessary to inquire into its wastes.
In no mineral is the waste more startling than in zinc. In Missouri it is necessary to leave supporting pillars as in coal mining. This can not be remedied, as the use of timbers is too expensive, but it causes a heavy loss. In the West, owing to the expensive treatment and shipment, much of the low-grade ore is left in the ground. In refining the loss is enormous, often as much as forty per cent. In order to produce zinc at a low cost there must be a heavy loss of metal. Better plants and equipment for refining, and the saving of all refusefor later use will be necessary if we are to conserve the zinc supply for future generations.
The supplies of many of the materials used in buildings and bridges, such as stone, gravel, clay, cement and lime are so great that they appear inexhaustible, and need of care in their use is not so much to be considered as is their development to take the place of other resources.
In the past they have not been used freely because wooden buildings have been so much cheaper; but cement, concrete and brick are now manufactured much more cheaply, on account of improved methods, while the price of lumber has been increasing rapidly. Within the last ten years, the value of cement manufactures has increased nearly six times. In 1900 we used seventy pounds of cement for each person; in 1907, two hundred and twenty-eight pounds. The value of brick and other products made from clay has doubled in the same period and is now $160,000,000, while the value of building-stone quarries is three times as great as it was ten years ago. There are many reasons why these materials should take the place of wood; as they are stronger, more durable, do not require paint, and are so much less liable to loss by fire.
The waste of minerals used in building is due toimproper and reckless methods of taking them from the ground and preparing them for market and in careless methods in manufacturing.
Of such minerals as quartz, grindstone, millstone, emery stone, mineral paints, talc and salt, there seems to be enough to meet the needs of the future as well as the present. Such supplies as sulphur, asphalt, magnesia, borax, and asbestos, as well as coal and iron, are not very plentiful. If used carelessly, they will be exhausted in a few years; if wisely, they may be expected to last beyond the limits of the present century.
Our supplies of quicksilver, antimony, graphite, mica, tin, nickel, platinum, and many minerals less well known, as well as our petroleum, natural gas, copper, gold, silver, lead, zinc, and phosphate rock will be almost exhausted well within the present century unless large new deposits are discovered.
Report of National Conservation Commission.
The Conservation of Mineral Resources. U. S. Government Reports.
Report of the U. S. Geological Survey.
Production of Gold in 1908. U. S. Government Reports.
Production of Silver in 1908.
Production of Lead in 1908.
Production of Zinc in 1908.
Production of Structural Materials.
About twenty pamphlets on other minerals.
Food is of two classes: vegetable, which comes directly from the earth, and animal, which has fed on vegetable life. This is, of course, a more concentrated form of food, and much less of it is needed to sustain life.
For the plentiful supply of vegetable food we must depend upon the fertility of the soil, as we have seen. Our animal food can not be classed among our natural resources, but as a product of them, and requires the same care and wise use.
In the early history of our country natural animal food was abundant. Fishes swarmed in the sea, lakes, and streams. Wild turkeys and other game birds, deer, and bison formed a large part of the food of our forefathers. But these have been gradually disappearing. We have caught and destroyed so many fish that we have only a fraction of our former number. The game birds have disappeared either because they have been killed in greatnumbers or because their nesting-places have been destroyed. Of the big game nothing is now left except in a few remote regions, and it is growing less plentiful each year.
Although large quantities of fish and game are marketed every year at certain seasons, they form a small fraction of the animal food required in the country, and we must now depend for most of our animal food, not on that which was at first given us for a natural resource but on that raised by man.
The poultry—the chickens, ducks, geese and turkeys; the cattle, beef and dairy, the hogs and the sheep that are raised in such vast numbers have taken the place of wild game. The cultivated varieties have higher food value, and are far more satisfactory, since they are ready for use at any time.
The conservation of our animal food resources presents a different problem from any other. It is true that we have wasted and exhausted our natural food supplies, but we must remember that to a certain extent their preservation was neither possible nor desirable. They have been driven out by advancing civilization.
Wild birds and animals leave as the forests are cut out, destroying their natural homes. Many of them can not be kept in captivity, so this supply never could have been regulated. It was necessaryto destroy some of them to insure man's safety, and others were needed for his use. But we can take their places with other animals which are better fitted for our food, and it is the task of keeping up a sufficient supply of these on the most suitable land and under conditions that will yield the best results, that constitutes the problem of the conservation of our animal food resources.
The raising of poultry and live stock on a large scale is a separate occupation, usually followed in a scientific manner and it is not of that industry that we need to speak, but rather of the benefit to every farmer and to the dwellers in small communities, of raising at least a part of the animal food used by the family.
Every farm has some bits of unoccupied land that can be fenced off for poultry. The gleanings from the fields will supply their food, and they will furnish meat and eggs for the family throughout the year, with enough left to sell to provide other comforts.
Live stock, cattle, sheep and hogs, as well as goats, horses and mules, are profitable to every farmer. Many farms have woodland; land that overflows at some seasons, and so is unfit for raising crops; or some rocky unproductive land where stock can be raised more profitably than anything else, and if every farmer would use all the land not suitable forfarm crops for pasture land the problem of an abundant meat supply, of dairy products and of fertilizers to enrich the soil would be largely solved. Some farming experts advocate letting each field in turn be used for pasture every five years, because the stock raised on it is equal in value to any other farm crop, and because the rest and fertilization almost double the value of the succeeding year's crop.
In the West and Southwest there are large tracts of public land untilled. Much of the land can never be used for agricultural purposes, because it is arid or mountainous.
This land is well adapted to grazing and the government has allowed free use of it to stockmen as pasture lands.
These public pasture lands are called "ranges." In the early years when this part of the country belonged to Mexico, the ranges were traversed by Indians and Mexicans who tended the herds of wild cattle and horses, raised mostly for their hides. But in the last quarter of a century the business has fallen into the hands of Americans who have introduced better breeds of higher value. In California, Arizona, and New Mexico there are now on the open ranges eight million sheep, nearly three million cattle and nearly a million horses, worth much more than one hundred million dollars. Wyoming and Utah have great sheep ranges and domuch to keep up the wool supply. On Texas, with its great cattle ranges, we depend for a large part of our beef and leather. In all these states where stock is fed on public land, there are many questions as to ownership of animals, rights of rival rangers, and other points to settle.
In some of these states the government has set aside national forest reserves. Within these is much good grazing land. In order that the government may have some revenue from the land, a regular price has been set on these forest lands. The charge is forty cents a year each for horses, thirty-five cents a year for cattle, and twelve cents for sheep. The land is properly divided, so that each kind of stock has suitable pasture. Each person who pays this tax is given a certain range and no one else is allowed to use it. There is sufficient pasture for each so that it need not be too closely cropped. A man may lease the same range year after year, may put down wells to supply his stock, live on it, and do many things to improve it.
The forest rangers who patrol the forest to watch for fires or for timber thieves also protect these stockmen in their rights and prevent trouble about grazing privileges.
Outside the forest reserves the grazing is free, but the advantages offered by this system are sogreat that nearly all rangers now wish to use the forest reserves.
As each ranger has his land assigned to him and no one else can use it, the grass is not overcropped as it often is in regions outside the forests. If pasture is good, so many herds are pastured there that soon the grass is all trampled down and eaten off. Large areas are so badly injured that it will not naturally resod itself.
Cattle men are asking that the same rules that apply to the national forests be applied to other public lands, so that the pasturage may be improved and each man may have protection in his rights.
If all grazing lands could be thus leased, it would give the business a far more permanent character, better breeds of stock would be raised, and individual owners would direct their efforts to improving both stock and pasture, after the manner of stock raisers on private lands.
So large a part of our animal food, our wool, our leather and many smaller needs depend on this industry, that every effort should be made to encourage it, and to provide the wisest laws and best methods both for conserving and developing it.
In conclusion it is interesting to note that the Department of Agriculture is making a study of food birds and animals in various parts of the world, and trying to domesticate them, to add to thevariety of our food supply. The quail, the golden pheasant and some species of grouse among birds, and two or three species of deer, including the reindeer, appear to be adapted to domestic life in this country, and may, before many years, become a part of the animal industry of the United States.
One who has never seen the big catches of fish brought in by a mackerel fleet or visited a wholesale fish market can have little idea of the importance of that industry, nor of the immense amount of food that is taken from the waters of the United States every year.
The word fish is made to include not only fish proper, but oysters, clams, scallops, lobsters, crabs, shrimps, and turtles. Fish is liked by most persons, is more easily digested than meat and is nourishing. As a food resource, it is different in many respects from any other. It does not exhaust the soil, nor take from the earth anything of value, the food of fishes consisting of water plants and animals that are not used by man in any other way. Fish also purify the water in which they live, and so cause a great, though indirect, benefit.
It is so plainly the wise thing, then, to keep our rivers stocked with fish and to use them for food only, that it seems that this valuable resource hasbeen more seriously and unnecessarily wasted than any other.
Fish are wasted on inland streams in the following ways: (1) By dynamiting. If a charge of dynamite be exploded on the bed of the river, great numbers of fish, killed by the shock, rise to the top of the water and can be taken. This practice was quite common at one time, but is now prohibited by law in several states.
(2) By seining. A seine or net is placed entirely across the stream, and all the fish which come down the stream are caught. In several states seining is not allowed at all. In others it is allowed only at certain seasons. And in still others the meshes of the seine must be large enough to allow all fish below a certain size to slip through.
(3) By catching with a hook, (angling) more fish than can be used or catching small fish and then throwing them away. This is a very common custom among sportsmen, but should be prohibited by law. From a certain small inland lake, it is said that during the entire season an average of five thousand fish a day is taken. These are almost all caught by summer residents, and it is unlikely that a large per cent. of them are eaten. In a few years the lake will be exhausted, and will cease to furnish fish for the people of the community, and there will, of course, be no more fishingfor the sportsmen. Equal waste is going on all through the summer at every resort where good fishing is to be had. Some states have laws regulating the size of the fish that may be caught and the number that one person may take in one day, and all states should have such laws.
(4) The worst waste of our fish is caused by turning large quantities of sewage or refuse from factories into streams. All the fish for miles up and down a river are often destroyed in this way. As we have seen, this is only one of the bad results of allowing such refuse to drain into streams; every state should have strict laws prohibiting it.
From the waters of the New England states more than five hundred and twenty-eight millions of fish are taken each year. Here are the great cod, mackerel, and herring fisheries. From the Middle Atlantic states, the great region for oysters, lobsters and other sea food, come eight hundred and twenty million more; one hundred and six million come from the South Atlantic states; one hundred and thirteen million, including the much sought tarpon and red snappers, come from the Gulf states; two hundred and seventeen million are caught in the Pacific states, including the great salmon catches; ninety-six millions are taken from the Mississippi River and its tributaries, and one hundred and sixty-six millions, largely salmon, from Alaska. TheGreat Lakes, with their pickerel, and other fine fresh-water fish furnish one hundred and thirteen millions and the small inland waters at least five millions more.
When they are taken from the waters the 2,169,000,000 pounds of fish caught in the United States are worth $58,000,000, but by canning, salting, and other processes of preserving, the value is greatly increased.
Fortunately, there is a method of conserving our supply of fish and not only preventing it from growing less, but of greatly increasing the number and improving the quality. The United States government has a thoroughly well organized fish commission, and many states and counties and even private clubs carry on the same work, which is a general supervision of the fish supply.
The government maintains stations which are regularly engaged in hatching fish, keeping them until the greatest danger of their being destroyed is past, and then placing them in various streams all over the country. These fish are always of good food varieties, and are carefully selected to insure the kind best suited to the stream, as to whether it is warm or cold, deep or shallow, clear or muddy, fresh or salt, slow and placid, or swift and turbulent, for each kind of stream has certain varieties of fish that are especially adapted to it.
With all these things taken into account, stocking only with the best food varieties, if a state has laws which require that a stream be kept free from sewage and refuse, that no tiny fish be taken from the water, and that only a stated number can be taken in a day by a single person, hundreds of small streams, ponds and reservoirs all over the country may be made to yield food supplies for the entire community near by.
Governor Deneen, of Illinois, in urging that streams be improved for navigation, says, "No estimate of the benefits to flow from stream development would be complete without allusion to the fisheries which have been established on the Illinois River, largely by restocking with fish from hatcheries. The fisheries located on that stream are second in value only to those of the Columbia River.
"Our experience thus far indicates that the food resources of the water may be brought up in value to those of the land. The Illinois valley contains 80,000 acres of water area and yields a fish product worth ten dollars an acre each year, very nearly all profit. The average value of the land product near by is a little less than twelve dollars an acre, and the labor, cost of seeding, and exhaustion of fertilization of the land must all be counted before there can be a profit."
In 1908 the United States Fish Commissiondistributed nearly two and a half billion of young fish and half a million fish eggs. These were such excellent varieties as salmon, shad, trout, bass, white fish, perch, cod, flat fish and lobsters.
The Bureau of Fisheries has its fish-hatching stations, its boats for catching fish in nets and its tank cars for carrying the young fish and eggs to the streams that are to be stocked.
Some of the most important work is interestingly described in a history of the Bureau of Fisheries issued in 1908. Among other things it tells of the lobster industry in both the Atlantic and Pacific Oceans. Lobsters are not found naturally in the Pacific, but shipments of lobsters have been made from the Atlantic coast. At the last shipment, after carrying them across the continent packed in seaweed, more than a thousand lobsters were safely placed on the bed of the Pacific Ocean.
On the Atlantic coast the lobsters were rapidly disappearing when the work of artificial "planting" of young lobsters and eggs began. The results can be seen now, for more lobsters are being caught each year, and the price to users is growing less as the supply becomes more plentiful.
The shad and the salmon are considered the finest of all fish for eating. Both are salt-water fish and both have the habit of going some distance up fresh-water rivers to lay their eggs. No eggs are everlaid in salt water. The mother fish goes up beyond where the tide comes in, so that the baby fish may have fresh water, which is necessary for them. Salmon and shad are never caught in the sea, but in the rivers, where they go in large numbers to lay their eggs in the spring. This, of course, means the destruction of both fish and eggs,—the present and future supply.
Shad eggs, or roe are sold in large quantities. The Bureau of Fisheries has planted three thousand millions of young shad in streams along the coast, and the eggs from which these fish were hatched were all taken from fish that had been caught for market, and would have been totally lost if the Bureau had not collected them from the fishermen.
Shad have been planted in the Sacramento and Columbia Rivers flowing into the Pacific Ocean. From these two sources they have spread until now they are found as far south as Los Angeles, and as far north as Alaska, a coast line of 4,000 miles, and it is said that more shad could now be caught in the Sacramento and Columbia Rivers than in any other water courses.
In addition to supplying the streams with young fish, it is necessary to leave a part of each river clear so that some of the fish may find their way up-stream to deposit their eggs. The salmon havebeen almost driven out from the waters of New England, except in the Penobscot River, where they have been kept by the watchfulness of the Fisheries Bureau. It is believed that the entire salmon industry in Maine would be wiped out in five years if fish culture should cease, and in the West, where the drain on the salmon for canning purposes is so heavy, artificial planting is used very largely to keep up the supply.
The experiments with oysters are full of interest. In Chesapeake Bay, where the best natural oyster beds were found, the demands on them were so great that the supply began to fail. In 1904 only a little more than one-fourth as many were produced as in 1880. The natural oyster beds were then marked and set aside as public fishing grounds.
These are to be used by whoever wishes but under strict protective rules. All other ocean beds may be planted with oysters by any one who leases the privilege from the state, and the right to collect the oysters from a certain bed belongs to the person who leases it as fully as does property on land.
Louisiana had a small number of natural beds. About ten years ago the planting of oyster beds began, and soon 20,000 acres had been planted. Conditions were particularly favorable, and within two years after the eggs or spawn were placed it was found that oysters three and a half to fourinches in size had grown in quantities of 1,000 to 2,000 bushels per acre. For a long time it has been the custom of fishermen to fatten their oysters by transplanting them to new beds where the food is abundant, and in a short time the oysters are much plumper, it takes fewer of them to make a quart and they also sell at a higher price, because they are of the finest quality.
These rich food beds are not plentiful, and many dealers are compelled to put small oysters on the market. The Bureau of Fisheries has made a study of these food beds, and by using fertilizer, such as farmers use on their land, have been able to make such beds of sea-plants grow where they do not naturally exist. These experiments have been tried only a short time, but the results have been entirely satisfactory, and it is hoped that before long, rich oyster beds may be made to grow in any part of the ocean where oysters will thrive.
In the Great Lakes the fishing is so heavy that it is probable that the supply of perch and white fish would be very low by this time if fish-culture had not been carried on to so great an extent. White fish, lake trout, pike and perch may be hatched in such large numbers as to keep the fisheries up to their present yield.
Another important work of the Fisheries Bureau is to keep up the supply of cod for the greatfisheries on the New England coast. For the last twenty years profitable shore cod fishery has been kept up on grounds that had been entirely exhausted before and also where cod had never been found before. At the wharves, government officers from the Fisheries Bureau board the fishing boats when they come in and take the eggs from the fish. These are taken to the government hatchery and either the eggs or the young fish are put back into the sea, and so keep up an unending supply.
Alaska is one of the most important fishing regions of the world. For this entire Territory, the United States paid Russia $7,200,000 and many thought that the money was practically thrown away, since it apparently bought for us nothing but barren, ice-bound shores. But since it became a part of the United States, Alaska has yielded fishery products alone amounting in value to $158,000,000—twenty-two and a half times the price paid. Of this, $49,000,000 came from the fur seal fishery, $86,000,000 from salmon and $23,000,000 from other fish.
About $1,500,000 worth of sponges are now taken from Florida waters each year. Naturally the failure of the industry would be a serious loss to the state. But the natural sponge beds are being rapidly exhausted, and the Bureau of Fisheries is convinced that the continuation of the sponge fisheriesmust depend on artificial planting. Sponges can be produced from cuttings at a cost much less than that of taking them from the natural beds.
Rhode Island has been successful in cultivating soft-shell clams and in increasing the area of its clam beds.
The Mississippi and its branches are subject to great floods in the early spring and occasionally in summer. After these floods millions of fishes are left in small pools some distance back from the river. These pools gradually dry up; the larger fishes are caught and the smaller ones die. The state and National Fish Commissions are now collecting these fishes in large numbers, and using them to stock ponds and rivers in other parts of the country.
They are used to supply many parts of the West and South and there is much greater demand for them than the Commissions can meet. Not that there is a lack of fish, for millions are left to waste because the Commissions can not distribute them rapidly enough to save them. If large storage ponds could be established to collect and keep the fish during the flood season, so that all the time might be spent in collecting fish during the overflow, and they could be sent out later, the amount of fish saved would be increased many fold.
The fish thus saved are being made to serve another useful purpose. Pearl buttons are made from the shells of mussels or fresh-water clams. This business, which is now worth $5,000,000, can not last many years unless some means of increasing the supply of mussels can be devised.
Now these men, who are always studying new plans, have thought of a wonderful way in which to let the fish help in carrying on this work. They obtain the mussel eggs, and when they are hatched place them in the pools with the fish from the overflowed lands. The tiny mussel larvæ attach themselves to the fish and are carried to the rivers and ponds with the fish. Soon they are ready to drop to the bottom and find food for themselves.
In this way 25,000,000 mussels were carried last year to streams where mussels are known to thrive. If these mussel-bearing fish can be obtained by farmers having private fish ponds, the ponds can be drained each year and the mussels gathered, thus adding considerably to the owner's income, and also keeping up the pearl button industry, in addition to the food supply which he gains from the fish.
Enough has been said to show clearly how desirable and how possible it is to conserve and increase our fish supplies. With the coöperation of all who waste the fish at present, and those who might aidin stocking the streams, we could add greatly to the food supply of the nation at a less cost than in any other way.
Grazing Lands. Report National Conservation Commission.
Grazing on the Public Lands. (Jastro.) Report Governor's Conference.
The Grazing Lands and Public Forests of Arizona. (Heard.) Report Governor's Conference.
Grazing Problems in the Southwest and How to Meet Them. Bulletin, Dept. of Agriculture, 5c.
Reports of the Bureau of Animal Industry. Dept. of Agriculture.
Distribution of Fish and Fish Eggs. Dept. Commerce and Labor.[B]
Reports of the Commission of Fisheries.
National Fisheries Congress.
If we look at a watch, we see that one wheel can not move until the one next in order to it moves, and that, in turn, must be set in motion by another wheel. In the same way nature adjusts itself in its various parts. Before man enters a region, the balance is perfect. Plants crowd each other out of the way, the weaker giving place to the stronger; then insects come to destroy them. These insects are destroyed by birds, small mammals or other insects. The birds are killed by animals and other birds, which in turn are the food of larger animals. And so through all nature runs this law of balance; nothing increases in too great a proportion.
But when man comes, he thinks only of his own needs and wishes and begins at once to upset the delicate balance. Year after year, he plants large fields of a single crop, and, calling other plants weeds, because they hinder the growth of his grain, he drives them out entirely. The insects that feed on these plants, finding no food, soon disappear,while the ones which feed on the farmers' crops, finding food so plentiful, are able to increase in great numbers. They increase all the more rapidly because man, not knowing or not caring to know who his real helpers are, has killed and driven away the birds that would feed on them.
In order to readjust matters, he must learn how to destroy the insects, or he can not have crops. Both the plant enemies, the weeds, and the insects are always trying to bring about nature's balance again by driving out the over-abundant field crop, so he must constantly fight them in order to secure his harvest.
In no country is more harm done by insects than in the United States. The losses to live stock and to plants, both growing and stored, resulting from insects are greater than all the expenses of the National Government, including the pension roll and the yearly maintenance of the army and navy.
Immense as is the value of our farm products, it would be much greater if it were not for the work of these insects. Careful calculations indicate that this loss will amount to not less than the enormous sum of $1,100,000,000 annually and probably far more. The loss is usually estimated at ten per cent. of the crop, but often is much heavier than this, and many indirect losses are not taken into account in this table, though we shall speak of them later.
Most insects pass through four stages: (1) the egg; (2) the worm or larvæ; (3) the chrysalis, cocoon, or pupa; (4) the full-grown insect or imago. Butterflies, moths and beetles are examples of insects in this last stage.
As eggs, they are, of course, harmless, and during the chrysalis state they lie perfectly inactive and are harmless, but many of them are very destructive when they are worms or larvæ, others do most injury in the full-grown state.
The insects that man has most reason to dread are: (1) Plant-lice, tiny insects with soft bodies, usually green. They attach themselves to the stems and leaves of plants and suck their juices, leaving them to wilt and die. They are found on many kinds of plants—on corn, wheat and other grains. They also flourish on garden vegetables and flowers.
(2) Scale insects. These are flat and appear to be only a scale on the stem or fruit. They are usually covered with a hard crust-like covering and are found on trees and bushes. They are usually the color of the bark on which they are found.
(3) Worms and caterpillars are soft-bodied, the bodies being in segments, and either smooth or covered with short bristly hair. They spend nearly all their time in eating, and do immense damage to the foliage of trees and vegetables and to fruit.The adult is a moth or caterpillar. This class is among the farmer's worst insect enemies.
(4) Borers attack trees and tough-stemmed plants. The eggs are laid on the stems, and after hatching, the larvæ bore into the stem or under the bark, causing the foliage to wilt and die. We are all familiar with what we call "worm-eaten" wood, with canals that have been eaten by these borers running through it in all directions. This completely ruins some of the best forest trees for lumber, and makes one of the greatest losses of the forests.
(5) Beetles are insects in the adult state. They have hard, shiny wing-covers. Many of the borers are beetles, and there are other varieties which do great damage, though other kinds are useful to man in destroying harmful insects.
(6) Bugs have their mouth parts prolonged into a sharp beak with which they puncture the skin or bark, instead of chewing the leaves, as do beetles. Flies, gnats, and other similar insects do not usually injure vegetation so much as do some other classes of insects, the principal damage being done to fruits; but they have been found to be the cause of some of the most serious diseases in both man and the lower animals.
The Department of Agriculture divides the injuries done by insects into classes according to theproducts injured, and in the list they place first the injury done to cereal crops.
The insects which damage the corn crop most seriously are the corn-root worm, which feeds on the roots of young corn, causing it to fall over and die, and which sometimes takes the whole corn crop of a large region. The next most important is the boll-worm or ear-worm. Most persons have seen this worm in the ears of sweet corn; ninety ears out of every hundred contain a worm which destroys from one-tenth to one-half the corn. Some years every ear in large regions is infested. In the South the field corn is attacked as badly as the sweet corn, but in the great corn states the injury is much less. Even here, however, the total loss is very great.
Almost equally important is the damage wrought by the chinch-bug, which is also one of the greatest pests in wheat and oats.
Every year in different sections of the country, bill-bugs, wire-worms, cutworms, cornstalk borers, locusts, grasshoppers, corn plant-lice and other insects, destroy millions of bushels of corn.
Of the cereal crops, wheat suffers most from insects. Of the large number of insects that attack wheat, the three important species are the Hessian fly, the chinch-bug and the grain plant-louse or green-bug.
The Hessian fly has been known to destroy as much as sixty per cent. of all the wheat acreage of a state. Fortunately, this damage is done early in the year, so that when whole fields are destroyed they can be replanted with other crops and only the cost of seed and labor is to be counted as a loss. But more often the field is only partly destroyed by the fly; it is not necessary to replant, but the yield is small, often not more than one-third. Some years the loss from the Hessian fly is very heavy, at other times comparatively light, yet there are few years when the loss is less than ten per cent. of the total crop from this insect alone,—which meant last year a loss of 72,500,000 bushels.
The chinch-bug is responsible for the loss of five per cent., or one bushel out of every twenty. It attacks the straw, causing the heads of wheat to fall over and wither away.
The injury done by the green-bug comes just as the wheat begins to ripen, the tiny green creatures attaching themselves in great numbers to the heads of the wheat. Other insects which prey on the wheat crop are grasshoppers, the wheat midge, cutworms and army-worms.
If it were not for the attacks of these various pests the wheat crop would be at least one-fifth larger than it is. Instead of 725,000,000 bushels, it would be 870,000,000; which, with wheat at adollar a bushel, amounts to a loss of nearly $150,000,000. Further, the world loses all this valuable bread-stuff.
Oats, rye and barley suffer far less than wheat from insect ravages but they are all attacked by the same insects, and on the whole, much damage is done to them each year.
Hay, clover, and alfalfa have their enemies which destroy a considerable part of the crops. The locusts and caterpillars, the army-worms and cutworms are the best known, but the tiny leaf-hoppers, which spring up at every step as we walk across the path or lawn, and the web-worms and grass-worms and grubs which work about the roots of the plants all do their part in lowering the production.
The principal insect enemies of cotton are the cotton boll-weevil, the boll-worm, the cotton red spider, and the cotton-leaf worm. The control of the boll-weevil is considered one of the most serious problems confronting the agricultural men of the country. In the first years after its introduction, it reduced the cotton crop fully fifty per cent., and was the cause, not only of serious loss to the farmers, but of the closing of the cotton mills in New England, of a scarcity of cotton cloth and a decided rise in its price. The boll-weevil is a beetle about a quarter of an inch in length. This little beetleeats into the heart of each boll, which soon falls to the ground.
The cotton-leaf worm formerly caused heavy damage, as much as $20,000,000 to $30,000,000 a year, but the loss has been greatly reduced by the war which farmers have waged against it. It is still estimated at from $5,000,000 to $10,000,000.
The boll-worm is chiefly destructive in the Southwest and does damage to the extent of $12,000,000.
All in all no article of commerce is more seriously affected by insect ravages than cotton, on account of its necessity, and the fact that it can be raised only in certain regions.
Tobacco is one of the principal crops in several states and it suffers heavily from insect damage. The large, showy tobacco-worm and the tiny tobacco-thrips cause serious injury to the leaves.
Sugar-cane has its insect enemies which take on an average one stalk out of every ten raised in this country, and reduce the crop in the same proportion.
The cranberry is another valuable commercial plant that has been greatly affected by an insect known as the cranberry fruit worm, but by spraying, growers have been able to reduce the damage from sixty per cent. down to fourteen per cent.
Garden vegetables suffer more than anything else from insects. Potatoes are attacked by two species of insects, both destructive unless held in check. One is the reddish brown blister-beetle. The eggs are laid on the ground, and do not become adult insects until the second year. The other is the striped Colorado beetle, the eggs of which are laid on the under side of the leaves, and develop into adults in a short time. Two broods of this beetle develop in a single season. Thus it may be seen that the two are entirely different, though they are often supposed to be the same. The Colorado beetle, by the immense damage it was doing to a necessary food crop, first led to a regular method of fighting insects in this country. This potato-bug is not feared as it was in the past, since farmers have learned to control it in a great measure, but they have only been able to lessen the evil, never to drive it out completely.
Other insects that destroy garden vegetables are the well-known green cabbage-worm, the harlequin cabbage-bug, the cabbage hairworm, the asparagus-beetle, the squash-bug, the squash-vine borer, the striped cucumber or melon beetle, the melon aphis, the corn boll-worm, the cornstalk borer and many others.
In addition to these insects that attack special plants, all vegetables are preyed on by thegrub-worm, the cutworm, the aphis and various tiny hoppers.
The grub-worms which work about the roots of plants are, in the adult state, the June-bugs or cock-chafers which fly about our lights in the spring and early summer, and which themselves do considerable damage by eating leaves of trees and bushes.
Orchards and small fruits suffer heavily from insect pests, both on account of the direct loss and on account of the expensive treatment. There are several hundred insects which ravage fruit trees, attacking the roots, trunk, foliage and fruit.
Among these are the scales, of which there are many species, but of which the most widely known and dreaded is the San Jose scale, so called because San Jose, California, was its starting place in America. It is the only one of the scales which, if not checked, will, in two or three years, completely destroy the tree on which it feeds. It attacks the citrus fruits, orange, lemon, grape-fruit, and the apple, pear, and peach as well as small fruits, particularly currants.
Among the many varieties that do serious damage are the black olive scale, plum scale, hickory scale, locust scale, frosted black scale, red oak scale, the cottony maple scale, greedy scale and oyster shell scale.
The woolly aphis injures the roots of our fruit trees; the trunk and limb borers, the peach tree borer, the apple borer, all stand ready to assail the life of the entire tree. The various leaf worms attack the life of the tree also. The grape-leaf skeletonizer eats every particle of green from the leaves, leaving only the veins. The canker-worms and the destructive tent-caterpillars also cause the death of many fruit trees.
Of insects which attack the fruit, the list is long. The codling-moth of the apple causes a greater money loss than any other enemy of fruits. Various estimates of the loss have been made, and in general it is believed that it causes the loss of one-fourth to one-half of the apple crop of the United States each year.
The plum-curculio attacks nearly all stone fruits. Its natural food plant is probably the native wild plum, and the plum continues to be its favorite food, consequently this fruit suffers most from the attacks of the insect. In years of short crops very little fruit remains on the tree to ripen. But peaches, apricots and cherries also suffer heavily, and apples and pears in a less degree.
The insects which injure the hardwood forest trees are principally the leaf-eaters, such as the gypsy and brown tail moths, which have almost stripped the New England shade trees, and donegreat damage to the forests; the elm leaf beetles and the numerous borers, both beetles and grubs, which from eggs laid in or just beneath the bark, hatch into larvæ which burrow into the wood, destroying its usefulness for lumber. Among the borers which do most injury in destroying valuable timber are the hickory-bark beetle, the bark-boring grubs which kill oak, chestnut, birch and poplar trees, the locust borer, the chestnut timber-worm and the Columbian timber beetle.
All these represent the loss from insects to the growing product; but when it is stored, there is seemingly no less danger of attack by a different class of insects. These include grain weevils and beetles, flour-moths, the small fruit and vinegar flies, buffalo-moths and dozens of others.
After these comes the loss to man and animals from insects. The cattle tick alone, through the dreaded Texas fever, causes a loss of from $10,000,000 to $35,000,000 in various years. The ox warble also preys on cattle and causes a loss of probably $3,000,000 more. The buffalo-gnats, gadflies, and other flies do on the whole a large amount of damage each year.
Man has only discovered in recent years how serious a factor in his own health as well as comfort, is the insect life about him. This subject is more fully treated under the subject of health, sofor the present we need only say that flies, mosquitos and other insects are supposed to cause some of our most serious diseases, and to be the indirect cause of the loss of hundreds of millions of dollars and many human lives each year.
Having thus summed up the damage done by insects, let us see what may be done to prevent their spread and if possible drive out the most harmful species entirely. Unfortunately, that seems almost impossible; so far all man's efforts have only resulted in saving a larger or smaller proportion of the various crops each year.
In insect control we turn first to the natural means of destruction. Chief among these means are birds,—of which we will speak in another chapter,—snakes and toads.
Toads live entirely on insects and catch large quantities of them. It is estimated that a single toad is worth almost twenty dollars a year in a field or garden. English gardeners are said to pay high prices for them and to keep as many as possible in their gardens. Toads will eat almost any kind of insect, are absolutely harmless, and should be carefully protected.
There is one class of insects which, so far from being an enemy to man, combines with him to kill the harmful insects. Among these are the black beetles which feed on cutworms and other larvæwhich injure the roots of plants. Lady-bird beetles destroy large numbers of plant-lice, and the Asiatic lady-bird has been found to be the natural destroyer of the San Jose scale. These little insects are now being hatched in this country, and it is hoped through them to stamp out the pest. A number of larger insects prey on the smaller ones.
Other insects, such as the Hessian fly, the green-bug or spring grain aphis, the army-worm and various species of grasshoppers are killed by tiny parasitic insects whose eggs are laid in the bodies of the larger insects, but which, after being hatched, feed on them.
To these natural methods of control man has added others. Cultivation is one of these methods. As insects flourish when given an unusually large amount of food of a particular kind, and starve when that food is taken away from them, so rotation of crops proves to be one of the best means of getting rid of those insects which can not travel far for their food. Farmers who practise rotation of crops are much less troubled with insects that injure the roots of plants than those who do not.
One of the best means of preventing damage from the Hessian fly is to sow a narrow strip of wheat all around the edges of the field several weeks before the main crop is to be sowed. The flies willgather in this strip and lay all their eggs in the early wheat. Just before the main crop is sowed, the narrow strip is plowed up and thoroughly harrowed and the larvæ perish for want of food.
The best known means of getting rid of grasshoppers is to destroy the eggs. This should be done by plowing and harrowing all roadsides, ditch banks, uncultivated fields and grassy margins around fields in the fall or winter.
Fall harrowing and deep spring plowing will prevent many of the bugs and beetles which spend the larval state in the ground from hatching. This method will also destroy the plum-curculio in orchards.
In attempting to control the boll-weevil of the cotton fields, it has been found that the best method to pursue is the simple one of planting the crop very early, so that the cotton passes the danger stage before the insects emerge, and removing all the plants in the fall.
Worms that infest fruit can be checked for the following year by fall plowing in the orchard and by destroying the decayed fruit as it falls. The farmer who lets his decayed fruit lie on the ground is preparing for a heavy crop of insects to eat his fruit the following summer.
Fruit and forest trees are both protected by aburlap band or a band of "sticky" fly-paper placed around the tree, to prevent insects from crawling up.
The use of poison in destroying insects is now the one most generally and successfully employed by farmers and fruit growers.
Poisons may be liquid or dry. The liquid is made by mixing with water, and for large plants and trees is put on with a spray or force-pump that carries the poison to every part of the plant.
Some insects, such as beetles, caterpillars and grasshoppers, chew the leaves or stems of plants, and the poison may be applied to their food; but others, such as plant-lice, scale insects and all bugs suck the juice, usually from the stem or bark. Poisons must be applied to the insect itself to be effectual in this case.
These are some of the insect poisons most in use:
Paris green, which will kill all insects that chew the leaves, may be used in small quantities in gardens by mixing one-half teaspoonful to a gallon of water, or in large quantities with one pound to one hundred and fifty or two hundred gallons of water.
White hellebore is used to destroy currant worms and is usually dusted on dry.
Pyrethrum is used as a spray, mixing one ounce to two gallons of water, to destroy cabbage-wormsand many other garden insects. If the dry pyrethrum powder is blown from a bellows into a tightly closed room, it is said to destroy all the flies.
Bordeaux mixture is made by dissolving four pounds of copper sulphate in hot water and mixing with an equal quantity of a solution made by mixing four pounds of lime with water. This is then mixed with fifty gallons of water. Paris green is sometimes added. This mixture is largely used in orchards and for destroying insects on a large scale. It is also useful for curing diseases of plants.
An excellent spray for orchards both for removing fungous diseases and scale insects is a home-made lime-and-sulphur solution. Enough for spraying a large orchard is prepared as follows:
Add three gallons of boiling water to fifteen pounds of lime. Then add ten pounds of sulphur and three gallons more of hot water. Allow this to boil about twenty minutes in its own heat, then add enough water to make fifty gallons of the mixture. Dilute with water in the proportion of one part of the solution to seventy-five of water.
Small quantities are made by using a fractional part of this recipe.
Whale-oil soap dissolved in water and used as a spray is an effective remedy for the San Jose scale.
Kerosene emulsion is used to kill the insects which suck the juices of plants and trees. It ismade by mixing a half-pound of hard soap with one gallon of hot water and stirring into it, so as to mix thoroughly, two gallons of kerosene oil. This may be kept on hand for use, and is mixed with ten parts of water to one of the emulsion.
For use in large orchards force-pumps operated by compressed air and drawn by two horses are used. The spraying should be done as soon as the blossoms drop, and many orchards are sprayed three times in a season, but the work should never be done while the trees are in blossom. Vegetables should be sprayed many times through the season.
A careful study of these methods of control, adapted to the various plants and the insects which prey on them, with the natural enemies of insects encouraged and protected, would go far to prevent the wide-spread and serious damage now affecting our crops, our vegetables, our orchards, and our forests.
Circulars of the Bureau of Entomology. Dept. of Agriculture. List furnished on application.
Annual Loss Occasioned by Destructive Insects. Yearbook 1904.[C]
Value of Insect Parasitism to the American Farmer. Yearbook 1907.
House Flies. Dept. of Agriculture. Bulletin 71.
The Grasshopper Problem. Bulletin 84.
The Boll-Weevil Problem. Bulletin 344.
The Most Important Step in the Control of the Boll-Weevil. Bulletin 95.
The San Jose Scale. Yearbook 1902.
The Plum-Curculio. Bulletin 73.
The Apple Codling-Moth. Bulletin 41. Price 20c.
The Gipsy Moth and How to Control It. Bulletin 275.
The Brown-tail Moth and How to Control It. Bulletin 264.
The Spring Grain Aphis or Green-Bug. Bulletin 93.
The Army-Worm. Bulletin 4.
The Hessian Fly. Bulletin 70.
The Chinch-Bug. Bulletin 17.
The Principal Household Insects of the U. S. Bulletin 4.
Insects Affecting Domestic Animals. Bulletin 5.
Birds give us pleasure in three ways: by their beauty, by their song and by their usefulness in destroying animals, insects or plants which are harmful to man.
But although they are among man's best friends they have been greatly misunderstood, so that to the many natural enemies that are constantly preying on birds, we must add the warfare that man himself wages on them, and the cutting down of their forest homes. This work of bird destruction has gone on until all the best species are greatly reduced in numbers and some species have been almost entirely driven out.
To see how serious a matter this is we must study the food habits of birds, and we shall find that although the different species eat a large variety of food, in almost every case their natural food is something harmful to man.
The large American birds, the eagles, hawks, owls and similar kinds, are called birds of prey because they feed on small birds and animals. Someof these are of the greatest benefit to the farmer, while others are altogether harmful. Another large class of birds lives almost entirely on injurious insects and this class is entitled to the fullest care and protection from the farmer.
Still another class lives largely on fruits, wild or cultivated, and on seeds, which may be either the farmer's most valuable grains, or seeds of the weeds that would choke out the grain.
It can not be denied that birds often do serious damage through their food habits; but the great mistake that has been made in man's treatment of birds has been in hastily deciding that if birds are seen flitting about fields of grain they are destroying the crop. A better knowledge of their food habits will lead to proper measures for destroying the harmful kinds and protecting the useful ones.
Successful agriculture could hardly be practised without birds, and the benefit to man, though amounting each year to millions of dollars, can hardly be estimated in dollars and cents, since it affects so closely the size of our crops, the amount of timber saved for use in manufactures, and even the health of the people.
Here again we see the careful balancing that runs through nature; how carefully each thing is adjusted to its work. Naturally the balance between birds, insects and plants would remain true,no one increasing beyond its proper amount. But when man begins to destroy certain things, and to cultivate others, this balance is seriously disturbed. The birds that destroy weed seeds being killed, weeds flourish in such vast numbers as to drive out the cultivated crops. The birds which destroy mice, moles, gophers, etc., being killed, these animals become a nuisance and cause serious losses. If insect-destroying birds are driven out, the farmer will be at the mercy of the insects unless he employs troublesome and expensive methods of getting rid of them. Certain favorable conditions cause large numbers of birds to gather in a small region and they become a pest. Very careful observation has shown that in nearly every case the favorite food of the birds is something which is not valued by man, and if this food is provided, the farm grains and fruits will not be seriously molested.
Few birds are altogether good, still fewer are altogether bad; most species are of great benefit, even if at the same time they do some harm. Some birds do serious damage at one season, and much good at another. The most notable example of this is the bobolink, which in northern wheat fields is loved no less for his merry song than for the thousands of weed seeds and insects he destroys; while in the South he is known as the reed-bird or rice-bird,the most dreaded of all foes to the rice crop.
Flying down on the fields by hundreds of thousands these birds often take almost the entire crop of a district. The yearly loss to rice-growers from bobolinks has been estimated at two million dollars.
If crows or blackbirds are seen in large numbers about fields of grain they are generally accused of robbing the farmer, but more often they are busily engaged in hunting the insects that without their help would soon have destroyed his crop; and even if they do considerable damage at one season they often pay for it many times over.
Whether a bird is helpful or the reverse, in fact, depends entirely on the food it eats and often even farmers who have been familiar with birds all their lives do not know what food a bird really eats. As an example of the misunderstanding that is often found in regard to birds, when hawks are seen searching the fields and meadows, or owls flying about the orchards in the evening, the farmer always supposes that his poultry is in danger, when in reality the birds are quite as likely to be hunting for the animals which destroy grain, produce, young trees, and eggs of birds.
In order to correct such mistaken ideas the Department of Agriculture has made a most careful and accurate study of the habits of birds, and it isthe results of these observations that are recorded here.
Field workers from this Department who have observed the habits of the principal birds that live among men, have watched them all day and from one day to another as they fed their little ones, and, to be more certain of their facts, they have examined the stomachs of hundreds of birds, both old and young, to learn exactly what each bird had eaten. In this way they have proved absolutely that many species that are supposed to eat chickens, or fruit or grain, in reality never touch them, but are among the farmer's best friends.
Among other things they have learned that while they are feeding their young, birds are especially valuable on a farm. Baby birds require food with a large amount of nourishment in it that can be easily digested. Almost all young birds have soft, tender stomachs, and must be fed on insects; as they grow older, the stomach or gizzard hardens and is capable of grinding hard grain or seeds. The amount of food required by the baby birds is astonishing. At certain stages of their growth they require more than their own weight in insects. And the young birds are to be fed just at the season that insects do the most injury to growing crops of grain and young fruit and vegetables.
Birds vary so much in the kind of food eaten,not only by different varieties of the same species, but by the same birds at different seasons, that it is necessary to make a careful study of each bird to know whether, if he is sometimes caught eating cultivated fruit and grains, he helps in other ways enough to pay for it.
When insects are unusually abundant, birds eat more than at other times and confine themselves more strictly to an insect diet, so that at such times the good they do is particularly valuable.
Birds of prey may do harm in a particular place, because in that region mice, rabbits and other natural food are scarce, and they are driven to feed on things that are useful to man, while in places where their natural food is plentiful the same birds are altogether helpful.
In the same way, birds which naturally eat weed seeds frequently find these almost altogether lacking where the farms are most carefully cultivated, but in their place are fields of grain whose seed also furnishes them desirable food. Is it any wonder, then, that, their natural food being taken from them, they turn to the cultivated crops? The fruit eating birds seem always to choose the wild fruits, but where these are not to be had they enter the orchards and soon become known as enemies of the farmer.
A careful examination of the harm done by birdsleads to the belief that the damage is usually caused by a very large number of one species of birds living in a small area. In such cases so great is the demand for food of a particular kind that the supply is soon exhausted, and the birds turn to the products of the field or orchard. The best conditions exist when there are many varieties of birds in a region, but no one variety in great numbers, for then they eat many kinds of insects and weeds, and do not exhaust all the food supply of one kind. Under such circumstances, too, the insect-eating birds would find plenty of insects without preying on useful products, and the insects would be held in check, so that the damage to crops would be slight.
The following are examples of the food eaten by birds and the good that they thus accomplish to man:
During the outbreak of Rocky Mountain locusts in Nebraska, a scientific observer watched a long-billed marsh wren carry thirty locusts to her young in an hour and the same number was kept up regularly. At this rate, for seven hours a day, a nest-ful of young wrens would eat two hundred and ten locusts a day. From this he calculated that the birds of eastern Nebraska would destroy daily nearly 163,000 locusts.
A locust eats its own weight in grain a day. The locusts eaten by the baby birds would therefore beable to destroy one hundred and seventy-five tons of crops, worth at least ten dollars a ton, or one thousand seven hundred and fifty dollars.
So we see that birds have an actual cash value on the farm. The value of the hay crop saved by meadow-larks in destroying grasshoppers has been estimated at three hundred and fifty-six dollars on every township thirty-six miles square.
An article contributed to the New YorkTribuneby an official in the Department of Agriculture estimated the amount of weed seeds annually destroyed by the tree sparrow in the state of Iowa on the basis of one-fourth of an ounce of seed eaten daily by each bird. Supposing there were ten birds to each mile, in the two hundred days that they remain in the region, we should have a total of 1,750,000 pounds, or eight hundred and seventy-five tons, of weed seed consumed in a single season by this one species in the one state. In a thicket near Washington, D. C. was a large patch of weeds where sparrows fed during the winter. The ground was literally black with the seeds in the spring but on examining them it was found that nearly all had been cracked and the kernels eaten. A search was made for seeds of various weeds but not more than half a dozen could be found, while many thousands of empty seed-pods showed how the birds had lived during the winter.
In no place are birds more important than in the forests, where they save hundreds of thousands of dollars worth of valuable timber each year. In forests there can be no rotation of crops and no cultivation, and spraying, which keeps down the insect pests in the orchard, is impossible here because of the expense. It would not pay to spray two or three times a year a crop of timber that requires a lifetime to grow. So in the forests the owner must depend entirely on birds for his protection. How great the destruction of our forests would be is shown by the fact that the damage at present is estimated at $100,000,000, in spite of the fact that a vast army of birds is working tirelessly, summer and winter, to devour the insects! The debt of the forester to the birds can hardly be estimated.
A full variety of birds will thoroughly protect a farm and orchard. The sparrows will destroy the weed seeds; the hawks and kites, flying by day, will catch the meadow mice and other small mammals, and the owls will pounce on those that venture forth at night. Of the insect-eating birds, the larks, wrens, thrushes and sparrows search the ground for worms, eggs and insects under leaves and logs everywhere. The nuthatches, vireos, warblers and creepers search every part of the tree, while the woodpeckers tap beneath the bark for grubs and worms. The fly-catching birds catch their insectfood on the wing among the trees and branches, and, last of all, the swallows skim high in the air and catch the few insects that rise high above the tree-tops.
Thus each family has its part of the work and the good they do is almost too great to calculate. Without this check it would be impossible for any green thing to flourish. So vast an amount of food is required to feed the great army of insects that the task would be impossible in any other way.