Soap
As a preventive against, or as a cure for, the depredations of insects on cultivated plants, Soap is often used, either in the form of suds, or along with other remedies (e.g., Carbolic Acid and Paraffin), which it helps to keep mixed with the water. Where Onions or roots, such as Carrots and Radishes, are suffering from the inroads of larvae, great benefit is experienced from watering the plants freely with soapsuds twice or thrice. It is recommended also to mix the soapsuds either with equal parts of gas-water, or with gas-tar in quantity such as to cause a strong smell, sufficient to keep the insects from laying eggs on the plants. Soap-boilers' waste, i.e., the coarse, alkaline solutions that are formed as waste products in making Soap, have been found of service when used instead of the above mixture. Soapsuds are also used against caterpillars on Gooseberries and other plants, being applied by means of a syringe. When Soap is employed to cause insecticides to mix more readily with water, it is well to use Soft Soap, as being stronger, and better suited to effect the end in view. With its aid, a good many substances may be kept much more uniformly diffused in water than could otherwise be done. Carbolic Acid is prepared thus, in the proportion of one part of acid to ten of Soap, with which it is very thoroughly mixed. The mixture is then diluted to the desired strength; and the solution is sprinkled with a watering-pot on plants infested with Green Fly or larvae, &c. Soft Soap is also used in combination with tobacco-water, sulphuret of lime, sulphur, or other substances, as a wash for the trunks of Apple-trees infested with American Blight; for walls, to destroy the Red Spider; and against such other injurious creatures as live on the bark or in crevices of the walls on which trees are trained. In all such mixtures, the substances used along with the Soap should be thoroughly mixed with it, and water should then be added till the mixture can be painted on the bark or wall; or more water may be used, and the fluid may then be rubbed well in with a stiff brush, or may be thrown from a syringe upon the places to be cleansed.