Used in California against the cottony cushion scale and the brown apricot scale. Soaps, whale-oil, or fish-oil soap. — Soaps are effective insecticides for plant-lice. Dissolve in hot water and dilute so as to obtain 1 pound of soap for every 5 or 7 gallons of water. Commercial whale-oil or fish-oil soaps frequently injure tender foliage because of the free alkali which they contain.

An excellent fish-oil soap free from uncombined alkali may be easily prepared at home, as follows:

Six pounds of caustic soda ; l1/2 gallons of water ; 22 pounds of fish oil.

Completely dissolve the caustic soda in the water, and then add the fish-oil very gradually, under constant and vigorous stirring. The combination occurs readily at ordinary summer temperatures and boiling is unnecessary. Stir briskly for about twenty minutes after the last of the oil has been added. (New York Experiment Station.)

Soap and tobacco. - Dissolve 8 pounds of the best soft soap in 12 gallons of rain-water, and when cold add 1 gallon of strong tobacco liquor. For plant-lice.

Soda and aloes. - Dissolve 2 pounds of washing-soda and 1 ounce of bitter Barbadoes aloes, and when cold add one gallon of water. Dip the plants into the solution, and lay them on their sides for a short time, and the insects will drop off. Syringe the plants with clean, tepid water, and return to the house. For plant-lice.

Sulfur. - Fumes of sulfur are destructive to insects, but should be carefully used, or plants will be injured. The sulfur should be evaporated over an oil stove, until the room is filled with the vapor. The sulfur should never be burned, as burning sulfur kills plants. For greenhouse use. See p. 258.

Sulfur and water. - To 3 gallons of weak soap suds add 1 pound of flowers of sulfur and stir thoroughly. Apply as a spray. For red spider and mites.

Tanglefoot is a sticky commercial substance much used for banding trees. See under Banding, p. 286.

Tar is sometimes used to prevent the female and wingless canker-worm from ascending trees. The tar should be placed on cotton, or some material which will prevent it from coming in contact with the bark, and a band of the preparation is then placed around the trunk. Care must be taken to see that the tar does not injure the tree.

Tarred paper may be rolled loosely about trees to keep away mice, but it should be removed before warm weather. It is sometimes recommended as a preventive of the attacks of borers, but it very often injures trees, and should be used, if at all, with great caution.

Tobacco. - 1. Stems, placed on the walks and under the benches of greenhouses, for plant-lice. Renew it every month. 2. Tobacco-water, used with whale-oil soap.

3.  Dust and snuff. Snuff may be blown lightly on plants, as house-plants, for lice.

4.  Fumes. Burn dampened tobacco-stems. See Fumigation, p. 287.

5.  Nicotyl. Steep tobacco-stems in water, and evaporate the water.

6.  Tea, or common decoction. Boil the stems or dust thoroughly, and strain. Then add cold water until the decoction contains 2 gallons of liquid to 1 pound of tobacco.

There are various concentrated commercial preparations of tobacco which have recently been giving good results against plant-lice.

White arsenic. — See Arsenicals, p. 291.

White hellebore. — A light brown powder made from the roots of the white hellebore plant ( Veratrum album), one of the lily family. It is applied both dry and in water. In the dry state, it is usually applied without dilution, although the addition of a little flour will render it more adhesive. In water, 4 ounces of the poison is mixed with 2 or 3 gallons ; and an ounce of glue, or thin flour paste, is sometimes added to make it adhere. A decoction is made by using boiling water in the same proportions. Hellebore soon loses its strength, and a fresh article should always be demanded. It is much less poisonous than the arsenicals, and should be used in place of them upon ripening fruit. Used for various leaf-eating insects, particularly for the currant-worm and rose-slug.