DDT, the Insect Killer

One of the Allied news agencies collected more than thirty thousand articles, all written about DDT between May 1944 and October 1945 — the period in which the Allied war departments disclosed to the public the secrets of this wondrous preparation, which saved the lives of thousands, nay millions, of those who plunged into the depths of the war in swamps and jungles where sudden death lay in wait.

The war departments did not permit its use by civilians until last August, and it was natural that the advertisements should herald it in all manner of enticing styles. Some publicity bulletins have called it "the atomic bomb that is deadly to insects."

DDT was first known as a disinfectant in 1874 in Germany, but its merits as a powder deadly to insects were not discovered until 1939, when a Swiss scientist used it against the insects that were then wreaking terrible havoc on the potato crops, and against the lice creeping over the bodies of homeless refugees.

This scientist soon distributed it to his laboratories in the United States and Great Britain, to take the place of "pyrethrum," the well-known insect killer; and from that time enormous quantities of it were used, saving the lives of millions of fighting soldiers.

Its Nature and Its Merits

DDT is a transparent white substance with a faint, refreshing odor, formed by the combination of monochlorobenzene and chloral with sulfuric acid. It is ground together with other solid elements, and its effective strength depends on the materials with which it is mixed, the extent of its action varying as they vary. This powder can be dissolved either in water, in various vegetable oils, or in petroleum derivatives.

Insect-destroying preparations are poisonous either upon contact, killing the insect when they touch its body, or upon being eaten, or upon being inhaled. DDT is a poison on contact and, in the intestines, when eaten; and it is unique among the other preparations in the merit of destroying the insect that lands on it, or on which it lands, gradually and slowly.

Those in charge of its trials hope that its use will become general in the home, in public health, in livestock, forests, agriculture, and crops. Experiments to date have proved a great success in its use to exterminate insects on livestock without harming or injuring them — quite the contrary: sheep sprayed with it four times during the season gained 230 grams in weight daily.

On the agricultural side, however, the trials are not yet complete, and its far-reaching effect has been verified only in potato crops and the like. The quantity to be used for this purpose ranges between 225 grams and 450 grams for every 400 liters of the liquids prepared for spraying. This quantity is enough to wipe out moths and weevils — the two deadliest enemies of fields and orchards — within a mere two weeks.

Great Britain and the United States were the first to broadcast the results of DDT, for their armed forces used it on a vast scale to exterminate lice, mosquitoes, bedbugs, and flies. The principal hot regions of the world were dusted with it and, thanks to it, made fit for habitation after people had found it impossible to live in them. These results astonished people far and near, and they came flocking to the chemical manufactories to ask for it, until its average monthly consumption reached 3 million pounds — that is, 1,362,000 kilos. And the orders keep on increasing.

The specialists particularly recommend its use to prevent insects from creeping into food cupboards and food boxes, by coating these with it on the outside.

As for the manner of its use, it is as follows:

To exterminate flies and mosquitoes:

Mix 5 percent of it with 95 percent refined kerosene and spray thoroughly all walls, ceilings, doors, and windows, at the rate of 3 liters for every hundred square meters.

To exterminate bedbugs

A brush moistened with the above-mentioned mixture should be used to wipe the beds, the cracks, and the bedding; or 5 percent DDT powder, to be dusted in the required places.

To exterminate cockroaches

5 percent DDT powder, to be sprayed into the cracks, the holes, the corners of the kitchen, and the other places where cockroaches take shelter. We draw attention to the fact that the desired results do not appear until three days after its use, provided the powder remains in the places where it was sprayed.

Cupboards, tables, drawers, shelves, and refrigerators must be sprayed with a 5 percent solution of DDT in refined kerosene.

To exterminate ants

5 percent DDT powder, dusted over the sleeping places of dogs and cats, in the runs and burrows of mice, under the carpets and on the tiles, and in the kitchen. It is advisable to spray the surface of the carpets with a 5 percent solution of DDT. The dusting of this powder must be kept up for a long period, perhaps lasting weeks, because the ants do not come out of their nests all at once.

Moths of all kinds

Spray the places where moths may take refuge with the aforementioned solution — DDT in 90 percent refined kerosene — or with 5 percent DDT powder; the latter must be sprayed by means of an air sprayer, so that the particles of the powder reach every corner and crack and every fold of the clothes.

This is a brief glimpse of this wondrous powder. And it pleases us that it has lately come within reach of all citizens, since the DDT Company for Lebanon and Syria, whose head office is in the Sursock Building, Beirut, has succeeded in procuring it and selling it at low prices.