Administrative control.
While these insecticides of nature are often very effective and finally accomplish their purpose, man can not wait but must usually resort to artificial insecticides to save his crops. For centuries man has been fighting insect enemies. The Greeks mixed hellebore with milk to kill flies, and the Romans required the inhabitants of infested regions to kill certain amounts of grasshoppers. In the middle ages the methods used for the destruction of insects were largely of a spiritual nature ; priests marched around infested fields praying ; anathemas were pronounced over grasshoppers ; or the accused insects were summoned to appear in court and judgment was rendered in the form of an excommunication. Scarcely thirty years ago, two governors of states in America issued procla mations appointing days of fasting and prayer to stop the ravages of Rocky mountain locusts. It is only within the past quarter of a century that most of the modern scientific methods of control ling insect pests have been devised. Previously, American farmers resorted to hand-work or to simple mechanical devices, such as bands for canker-worms and codling-moth. The word "in secticide" was unknown half a century ago, and, according to the dictionaries when man kills an insect he is an insecticide, he may use an insecti cide, and he also commits an insecticide. Usually, however, the word is restricted to some material or spray used by man to kill insects.
We may classify the methods used against insect pests as : international, national, state, local or neighborhood and individual. The first three of these mostly comprise laws or commercial regula lations, by the enforcement of which attempts are made to prevent the spread of insect pests from one country or state to another, and also to provide for the introduction of beneficial insects. Neigh borhood and individual efforts usually aim at the immediate death of the insects either through the enforcement of municipal regulations, by the offer ing of prizes, by practicing better farm methods, or by the use of insecticidal batteries.
Laws or regulations are often necessary in insect warfare, but they must be supported by public opinion to be effective. Far-reaching and valuable results have been attained by interns: tional efforts in controlling insect pests by quar antine regulations and by the introduction of bene ficial insects. Nations can scarcely overdo this kind of control work against injurious insects.
Compulsory state legislation to control insect pests will often lack the necessary support of public opinion and hence be difficult to administer; attempts to annihilate the San Jose scale in Canada by the axe and fire were soon stopped by adverse public opinion. The state inspection laws to prevent the spread of insects by nursery men have accomplished much good. Local authorities can do much to check the ravages of insects over limited areas by offering prizes or insisting that owners of infested premises shall use certain destruc tive measures or pay for having the authorities do it. A few neigh bors can do much to mitigate the ravages of the hessian fly by com bined action in using early trap strips of wheat and sowing as late as practicable.
And yet, after all has been said and done by international, national, state or local authorities to stay temporarily the inevitable spread of the world's injurious insect fauna, each individual who raises crops will often find himself face to face with the problem of fighting successfully some insect pest or the loss of his crop. Legislation and inspection or fumigation certificates are then of no avail. Usually his parasitic and predaceous insect friends are also too slow. A nation may profit ably spend much money to introduce new insect friends; doubtless an extensive national quarantine would keep out some injurious insects for a time, and the state and local authorities can do much to check the spread of a pest ; but in the end the brunt of the fight will fall on the individual whose crops are attacked.