Battling the Bug Battalions
Insect marauders cost Canada $175,000,000 a year; hence the never-ending war being waged for their destruction
A. G. DEXTER
EACH year Canada is the cockpit of a struggle more fierce and sanguinary than words can describe, and while never a drop of human blood is shed, the financial loss to this Dominion is so staggering that— except to those whose duty it is to serve in the front line trenches—it must seem incredible. In recent years, with the rapid expansion of Canadian trade and commerce and the unprecedented prosperity which has prevailed throughout the Dominion, the average Canadian has looked about him with a pardonable sense of pride and satisfaction.
Such a feeling could scarcely exist if some grim god singled out, year after year, a flourishing city such as Saskatoon, Hamilton or Saint John, and destroyed it utterly and completely. Yet small foes, of whose existence many town-bred Canadians are unaware, year after year exact an equally terrible toll upon the wealth of this country. They are marvellously equipped for their mission of destruction. They have saws and knives for cutting, lances for piercing: their voracious appetites are never sated. They destroy to the very limit of their capacity, asking no mercy or quarter from a world which they regard as their legitimate prey, and yielding none.
A Loss of $175,000,000 a Year
TO SIXTY men has been allotted the task of fighting these minute foemen and the war is carried on with ever increasing ferocity. All the aids of science are called into play. Deadly poisons are compounded and scattered broadcast among the destroyers from airplanes, or sprayed over them in liquid form from the nozzles of high pressure hose. Their natural enemies are sought the world over and when found are brought in large numbers and liberated among them. They are infected with diseases; plagues are loosed upon them. They are burnt in flames or in acids; they are drowned; or are suffocated in nauseating sticky powders which are dusted over their bodies.
'YT’ET despite all efforts, these ■*ravagers, these insects, destroy every year in Canada the work of 100,000 ablebodied men—or five per cent of the bread-winning population—and Canada is much better off than other countries, particularly the countries of the Old World. Indeed, the destruction caused by insects upon field crops the world over is something terrible to contemplate. A distinguished United States scientist has stated that every year insects on the North American continent destroy the food produced by 1,100,000 men. Isolating Canada and estimating the loss in terms of dollars rather than in human labor, it can be said on no less authority
than that of Arthur Gibson, chief Dominion entomologist, that the annual toll of insects on field crops alone exceeds $100,000,000 annually, or ten per cent of Canada’s production in these industries. It is as if the people of Canada took this huge sum of money each autumn and cast it into the sea.
And this figure, large though it be, is not the total loss from the ravages of insects. If one includes the damage caused to the forests of Canada, the total is much greater. The Forest Insect division of the Dominion Entomological branch, from first hand investigation, has computed that one species of insect in ten years destroyed no less than 200,000,000 cords of spruce—or more than would be required to keep fifty large newsprint mills in continuous operation for fifty years. In pulpwood this represents a value of $3,750,000,000; in newsprint more than $7,000,000,000. Had this wood been saved, it would have created sufficient wealth to have paid off the funded debt of the Dominion and the nine provinces with more than enough left over to build the St. Lawrence Deep Waterway and the Peace River railway outlet.
Yet these are but two phases of the toll of insect
pests. Not only are field crops and forests destroyed, but insects also bring sickness and death to human beings and animals. Calculating all their ravages, the annual loss which Canada sustains exceeds $175,000,000. Curiously enough, on. seldom hears it mentioned. Being a loss occasioned by insects which are living creatures, produced and fed just as are other living creatures, in no sense horrifying to the sight but often very beautiful, the citizens accept their depredations as a commonplace, and those who carry on the war of extermination are frequently overlooked, or, worse, regarded as well meaning persons whose mental balance has been slightly disturbed by the activities of cute little butterflies or insignificant worms.
A Never-Ending Struggle
TN A WAY this never-ending contest between man and the insect world is unequal. Although so much brainier, longer lived and more powerful, man is poorly equipped to do battle with the myriads of the forest and field. To begin with, insects lived on this earth untold ages before the first man appeared. And in the dim beginnings of the human race, in fact down to fairly modern times, most men desired only to grow enough food for their own use. This permitted the insects a more or less free hand: there was enough for both. Yet even in early times there were occasions upon which countless thousands of men died—the victims of insects. Plagues, similar to those of biblical fame, are not lacking in historical foundation. During all these countless centuries the insects kept on multiplying and perfecting their equipment for life.
Then came the day of large scale agricultural production. The insects at once found their feeding and breeding grounds vastly enlarged. They were perfectly equipped for these greater opportunities and took immediate advantage of them. The boll weevil, for example, lived in Mexico for centuries. It spread very slowly, because cotton growing was not common. However, when cultivation of cotton became general in the southern states, it found its habitat vastly enlarged, and has spread farther in recent years than it would have done in a thousand under the former conditions. And with this large scale production, the ravages of the insects were magnified and became apparent to man, with the result that the task of destroying them became a problem of first importance to governments.
Canada, being one of the leading agricultural countries of the world, was one of the first to meet the challenge of the insects. The Entomological Branch at Ottawa was formed in 1909, and today is one of the most efficient and well equipped organizations in the Dominion. Then, too, many provinces now maintain entomological departments which co-operate with the Federal branch.
Entomology is not an old science: it is of comparatively recent origin. So far, while the work of entomologists has been of incalculable benefit to the world, it would be true to say that the full extent of the insect problem is only being uncovered. We are now told that there are no less than 650,000 distinct species of insect known to entomology, and it will be necessary, in so far as this Dominion is concerned, to carry out a careful and complete study of the life history of each one which might in any way menace the crops or the forests of Canada. And each study may require many months, perhaps years, to complete.
Set a Bug to Scotch a Bug
ONE of the most encouraging discoveries has been that there are insects which live upon insects. Swift hit upon a great truth when he penned the lines:
Has smaller fleas that on him prey;
And these have smaller still to bite ’em, And so proceed ad infinitum.
And so one of the most enthralling chapters in entomology deals with the manner in which parasite insects have been discovered and loosed upon their natural prey, thus removing the menace of a destructive insect and enabling wealth to be produced.
Take the fig industry of California. Fig trees were introduced there early in the present century. However, a destructive insect appeared in vast numbers which, although it did not kill the trees, prevented them from bearing fruit. Government entomologists were called in, and finally the marauder was discovered.
But how could it be controlled? And where could a parasite be found which would destroy it? Entomologists were sent to every fig-producing country in the world. For years their search was vain. Finally, however, on the steep hillside which rises behind the storied city of Smyrna, they found the destroying insect and a parasite which lived upon it. The parasite was carefully crated and brought to California. Today, Canada depends largely for figs upon California.
Or take the pineapple industry in Hawaii. The climate of the island was perfect for pineapples, but the plants, when imported, would not bear fruit because of the injurious effects of an insect.
Where could a parasite be found which would destroy this insect?
Entomologists searched near and far, and finally found the parasite. A shipment was carefully prepared and brought to Hawaii. But the change in environment was too great and the parasite died. Thereupon the parasite was brought from its natural habitat to Hawaii by gradual stages from island to island, and finally was acclimatized to conditions in Hawaii. Today, the pineapple crop is one of the largest items in Hawaii’s production.
Nor have Canadian entomologists been behindhand in invoking the aid of nature in the controlling and destruction of insect pests. A few years ago the fruit industry of Nova Scotia was menaced by an epidemic of apple suckers. One of the entomologists noticed that some of the suckers were stricken with a disease caused, apparently, by a fungous parasite which did not damage the trees. The fungous parasite lent itself readily to artificial dissemination and the apple suckers were quickly destroyed.
The many facets of the insect problem require a highly
organized department of government. The Entomological Service at Ottawa is divided into four branches. One department deals with field crop and garden pests; another has charge of forests; still another is charged with collecting information about insects from all countries in the world. Warning of insect outbreaks is received from and givdn to the United States government, and in this way Canadian scientists are informed of insects which are prevalent along the boundary. It is then possible by means of scouting parties to locate the first invasion of this country, and control measures can be applied immediately.
The experience of the past has proved the necessity of maintaining these frontier patrols. One such is the grasshopper patrol in the prairie provinces, which will give adequate warning to western farmers of an impending recurrence of the plague of 1919 and 1923. Time was, before these patrols were inaugurated, when destructive insects could enter Canada unperceived. They came unheralded. They established themselves in small areas, where they reinforced their numbers until suddenly they swept across the face of the country, devastating crops, felling forests.
There is the case of the larch sawfly, which thirty years ago suddenly leaped from the status of a moderate destroyer to that of a plague. It swept westward from the Maritime provinces, where it gained its first foothold in Canada, to Manitoba. Over this vast area so complete has been the destruction that only an occasional larch over four inches in diameter escaped. The smaller trees, however, remained unharmed. Everywhere, therefore, fine young stands of this useful species are in evidence today, and the hope of bringing back the larch lies in preventing a recurrence of the scourge.
In 1913, the late Dominion Entomologist, Dr. C. Gordon Hewitt, found a foreign parasite which lived on the larch sawfly. He introduced this parasite into Manitoba. The parasite lays its eggs on the injurious insect, so that the young parasite, as soon as hatched, makes a meal of it. This means that the next insect generation will find an increase in the parasite and a decrease in the sawfly. Collections of sawfly cocoons have been made on several occasions since 1913, but not until 1918 did observations indicate an increase in the number of parasites. It was then found that the parasites had spread many miles from the point where they were first released, and that in the local area sixty-four per cent of sawfly cocoons were parasited. Last year the parasite was introduced from Manitoba to Ontario, Quebec and New Brunswick.
Then there is still another division of the Entomology department, which collates and systematizes all information gained by other divisions. A great national collection of insects is being created to enable rapid identification of new insects which may appear from time to time.
Enter the Corn Borer
"D ECENTLY a distinguished entom“ ologist complained bitterly of the unfairness of a publisher who had asked him to write an outline of the science in a book of 500 pages. The scientist complained that he could not even begin to introduce the subject in so brief a space. Likewise it is difficult to give in one article a fair summary of the work being done by the Entomological Branch at Ottawa. Perhaps the chief interest will centre not so much upon the scientists and the branch, as upon the insects which they strive to control. Among the most destructive are the corn borer, grasshopper, army worm, potato stem-borer, carrot rust fly, Hessian fly, cutworm, wireworm, wheat stem sawfly, chinch bug and the clover seed midge. Of these the corn borer, the chinch bug and the Hessian fly are not native to this continent. The others, however, preceded man in the possession of this continent, and were ready and waiting for the greater opportunities which were presented by the cultivation of the soil.
The Borer—Arch Foe
'“PHE corn borer bears a name as dreaded and fearful in the corn growing belt of Ontario as was the name of Douglas along the border marches of England. The ravages of this pest have reduced Ontario’s corn acreage from 449,176 acres in 1920 to 326,964 acres in 1927, and the yield per acre from 9.45 tons to 7.57 tons. There are many corn-growing areas in Ontario to which the borer has not spread, owing to the rigid control measures of the Federal and provincial governments. In the infested area which borders on Lake Erie, the acreage fell by more than fifty per cent and the yield to a greater degree. Canning factories which once were prosperous are bankrupt and hundreds of employed are seeking work elsewhere.
Last summer a farmer from Essex county—at one time the greatest corngrowing county in Canada—came to Ottawa, and the greatest moment on his trip was when he ordered corn on the cob. He said that since the advent of the borer, corn had not been eaten in Essex county.
What sort of insect is this destroyer, and whence came it?
The corn borer gained entry to North America in 1908. In that year there occurred a shortage of broom corn in Canada and the United States. By broom corn is meant the corn stocks which are used in production of household brooms and whisks. Broom manufacturers imported corn stalks from Austria-Hungary and these stalks were infected with the malignant borer. No variety of corn is immune from their attacks. Fields of forty and fifty acres have been so badly infected that at the end of the growing season they appeared, while yet green, as though they had been pasture for hogs, and were of no value whatever. As many as 115 borers have been found in a single stalk. The corn borer was first detected on this continent in the State of Massachusetts. Its spread at first was slow. However, as it gained in numbers and strength and became acclimatized, it conquered new areas more rapidly.
Just how it entered Canada is a matter of conjecture. Perhaps it came direct from Austria to a little broom factory at St. Thomas. There is also ground for the belief that it came from the United States. In doing so, the insect profited by a combination of circumstances so remarkable as to be scarcely believable.
The Pirate Invades Ontario
rT'HE first outbreak in Canada was L discovered about eleven years after the insect had been found in Massachusetts. In the meantime it had spread north through the State of New York to the shores of Lake Erie. The subsequent events probably occurred in this manner. A stook of corn, badly infected with borers, was blown from a cornfield close to the United States side of Lake Erie into the water. This frail bark, freighted with a more ruthless and ferocious crew than ever was carried by pirate ship on the Spanish Main, was blown to and fro across the lake; buffeted by storms; bruised by keels of cargo ships. Finally, by a tragic stroke of circumstance it was thrown high up on the Canadian shore by a mighty wave in one of the autumn gales which swept the lakes in that year. It rested close to a cornfield in the county of Haldimand. The sodden stalks dried, and the fiery sun in the following year warmed the caterpillars into life. The moths appeared and flew out over the richest corn-producing area of Ontario, and thereafter, until last year, the corn production waned and the massed efforts of the scientists of the Federal and Provincial governments have been arrayed against this carrier of havoc and destruction.
From these small beginnings—a few thousand borers imported in 1908—has grown up a mighty horde of insects. The infected area gradually spread. Today, thirteen states across the boundary are fighting the borer, and the entire corngrowing area of southwestern Ontario has been infected. The United States government spent $10,000,000 in 1927 in an attempt to restrict the borer to the area already infected. The Canadian Government, through the Entomology Branch, is exerting every effort to prevent the borer spreading westward to Manitoba and Saskatchewan and corn-growing areas in eastern Canada. All infected areas are quarantined and the movement of corn or parts of the plant from such areas is prohibited.
Two measures of control were devised. The borer winters in the stalk. If every vestige of the stalk, including stubble and shaft, is destroyed, the borer will also be killed. The Ontario Legislature has enacted a law which compels farmers to clean up cornfields. This law was enforced, at first despite the complaints of the farmers. Not infrequently, the provincial inspectors were defied by farmers and the police had to be summoned. That was before the ruinous activities of the borer were appreciated. Today, farmers realize that unless the borer is conquered their cornfields will be a total loss.
V\ 7 HILE farmers were being taught to W fight the borer by cleaner methods of farming, the entomologists searched Europe for a parasite which lived on the destroyer. They found several and the most promising is known as the Exorister Roborator, a fairly large and wasp-like fly. It is the deadly foe of the borer. This fly is armed with a long lance. It is delicately sensitized so that it can detect the presence of a borer within the cornstalk. Once detected, the parasite performs its function in an efficient and yet horrible manner. It plunges its lance through the stalk and into the vitals of the borer, keeping it there, however the victim may squirm, until it has laid its eggs. These eggs hatch in due time and the young parasites gain in strength in their early hours of life by eating out the vitals of the borer.
The first shipment of these parasites was carefully packed, with sufficient borer-infected cornstalks to keep the parasites alive, and were sent to this continent. Although enfeebled by the change in climate the parasites lived and reproduced. In 1923, the Federal government entomologists liberated 120,000 parasites in the borer infected area of Ontario and recent inspections show they are getting acclimatized and probably will soon become firmly established. The parasite is perfectly harmless to field crops. After several years’ unremitting effort, the menace of the borer is at last being removed, corn acreage once more is on the increase in the Niagara peninsula, and the future looks brighter.
Another Marauder From Europe
THE Hessian fly is another destroyer which has exacted a terrible toll from the wheat fields of this continent. It attacks wheat in its early stages of growth. This fly, like the borer, is a native of Europe. It was first carried to North America in 1776, when the British government dispatched Hessian troops to aid in quelling the rebellion of the colonies. Concealed in the army supplies which came with these troops, was a ravager destined to destroy wealth upon a scale in comparison with which the cost of the revolutionary war is as a match flare to a forest fire. The Hessian fly found a bountiful sanctuary in wheat fields nearby the battlefields o*f the revolution. Gradually it spread westward, following the conquest of the plow into the central and mid-western states of the union, and finally northward into Canada. In the first 124 years of its career in North America, the Hessian fly destroyed crops to the extent of $100,000,000. Destruction in this century is estimated to have at least doubled this total.
Then thermis the wheat-stem sawfly which has preyed for years upon the wheat crop of western Canada. In 1921, the damage caused by this insect was estimated at $2,000,000, and in 1926 the losses in Saskatchewan alone were reported by Federal entomologists at $12,000,000. This was an insect which for many years defied control efforts of the scientists. Then one of the Federal entomologists made a discovery which has saved the Dominion hundreds of thousands of dollars. Like many another discovery this one was the fruit of painstaking study and reflection. It was observed that the grubs of the sawfly do not cut the stems of the wheat until the plants begin to lose their sap. Farmers were advised to cut their grain a little on the green side. In this way the menace of the sawfly is removed and another barrier to successful agriculture overcome.
However, the worst insect plague which has ever afflicted the prairi^ provinces occurred in the years 1919-1923, when hordes of grasshoppers coming from the south swept bare the southern fields of Manitoba, Saskatchewan and Alberta. The loss of one half the grain crop appeared to many to be inevitable. The three provincial and the federal governments at once formulated a concerted plan of defense. The insects were studied. A new and particularly deadly poison bait was devised and upward of 70,000 tons of it were shipped to the infected area. The grasshoppers were killed, and crops within the area, estimated to be worth $80,000,000, were saved. The cost of the campaign was $1,700,000. Again in 1924, there was another outbreak of grasshoppers. This time it was in British Columbia. Poison was sent promptly and the danger averted. There is no longer need to fear the grasshopper. But adequate time to prepare poison and distribute it is required if outbreaks are to be quelled without damage to crops. Hence the border patrol.
Cutworms are another scourge of field crops. There are several varieties. The red-backed cutworm was very active in Saskatchewan in 1925 and 1926, causing damage to grain crops estimated at $6,000,000. The pale western cutworm is another destroyer which has been very active in the prairie provinces. The army worm is yet another variety which makes occasional destructive forays into Canada. Control of these insects is being sought by means of poison bait.
In guarding the field crops of Canada, the entomologists do not forget the insects which prey upon human beings and animals. War has been waged persistently upon the house fly. Various toxic sprays, now in common use, have been evolved. The mosquito, also, is being attacked successfully.
Often control of insect and animal pests is made more difficult by the activities of well-meaning but ill-informed citizens. There are those for example, who shoot crows, in ignorance of the splendid work these birds perform in assisting to control the army or cutworm. Gulls have been known to subdue a rising plague of grasshoppers. Then there is the oft told story of the farmer who shot the weasel because he lost a few chickens, only to lose more from the rats which the weasel had preyed upon. After all, the most efficient destroyers of insects are their natural enemies—the birds, frogs and toads. These should be fostered and not slain, for man needs every ally in his fight against the bug battalions.