Tephrosia virginiana is known as devils-shoestring. It is a pretty little native plant, which prefers dry, open, somewhat sandy places. It has long been known to possess insecticidal properties. The most toxic samples of devils-shoestring were slightly more poisonous than pyrethrum, but less poisonous than derris. Against five species of insects the plants showed promise as a contact spray. Technical Bulletin No. 595 of the Department of Agriculture outlines studies of the possibilities of devils-shoestring as a commercial source of insecticides.

Liliaceae (Lily Family). The foliage and rootstock of most species contain a poisonous juice. Amianthium muscaetoxicum, crowpoison, shows promise as an insecticide against the house fly, cockroaches, grasshoppers, and bees. It is inefficient against tent caterpillars and aphids. The powdered bulbs and leaves are used as dusts. Water extracts show a slow but considerable insecticidal effect against Colorado potato beetle larvae and cockroaches.

Melanthium virginicum, bunch-flower. L. H. Pammel in 1911 stated that the bunchflower had long been used to poison flies.

Schoenocaulon officinale is commonly known as sabadilla. R. J. Dicke in a thesis submitted to the University of Wisconsin in 1943 reviewed 76 references on this plant, which has been used as an insecticide since the sixteenth century. The University of Wisconsin has patented a method for increasing the toxicity of sabadilla: Heating the powdered seed in kerosene or other solvent to 150 C. for 1 hour. Sabadilla is effective against squash bugs, chinch bugs, harlequin bugs, and lygus bugs. Scientists in the Department of Agriculture in 1949 began a chemical study of the constituents of sabadilla seed.

Veratrum. Three plants are popularly called hellebore Veratrum album, V. viride, and Hellebores niger. The term hellebore is incorrect when it is applied to the first two plants. The last, which is the true hellebore, grows in Europe and is not a commercial product in the United States. V. viride is the American plant. Powdered roots of the first two plants prevent the emergence of house flies from horse manure.

Veratrum viride is often called American false-hellebore, swamp hellebore, Indian poke, and itchweed in the United States. Its active principles are alkaloids, which are toxic to man. Its value as an insecticide for the control of chewing insects on ripening fruit is due to its rapid loss of toxicity on exposure to light and air.

Meliaceae (Mahogany Family). Melia azedarach is called chinaberry. Water extracts of the berries affect cockroaches slightly but are more toxic against honey bees. Leaves applied to the soil greatly reduce attacks of termites. An alkaline extract of the fruits is effective against aphids. Cultivated plants sprayed with extracts of the chinaberry leaves are not touched by locusts. The active principle is soluble in hot water, alcohol, chloroform, or benzene but not in petroleum ether.

Myrtaceae (Myrtle Family). Pimenta racemosa is the bay-rum tree. The oil of the leaves is toxic to mosquito larvae. Bay rum has been used in Venezuela to kill insects. A foreign patent covers its use in a mixture of several substances. Applied to summer garments, it protects the wearer against gnats. Effective as baits to attract Japanese beetles are 90 parts of geraniol and 10 parts of the leaf oil of a Pimenta species, or 90 parts of anethole and io parts of the oil.

Pedaliaceae. Sesamum inducum, sesame. The seeds yield sesame oil, which contains sesamin, a powerful synergist for pyrethrum. In the Second World War the Armed Forces used more than 40 million aerosol bombs containing pyrethrum, liquefied gas, and sesame oil. The later bombs used 8 percent of the oil in the formula. Sesame oil also acts as a synergist for rotenone.

Ranunculaceae (Crowfoot Family). Delphinium consolida is called field larkspur. The oil from larkspur seed tested as a contact spray (2-percent emulsion) was effective against spider mites and aphids but had little value against some other insects. The alkaloids of this plant were also effective against insects in various degrees.

Rutaceae (Rue Family). Phellodendron amurense, the Amur corktree, is native to several Asiatic countries and was introduced into the United States in 1856. The unsaponifiable portion of the oil of the fruit is toxic to house flies in acetone solution but not in high-boiling kerosene. The residue of the fruit, the oil having been removed, is toxic to mosquito larvae, house flies, and larvae of codling moth. The material is a fast-acting poison like pyrethrum and nicotine.

Zanthoxylum clavaherculis, the southern prickly-ash, contains asarinin, a compound structurally related to sesamin and, like it, a good synergist for pyrethrum against house flies. The southern prickly-ash also contains herculin, a pungent substance highly toxic to house flies. It is closely related to several other isobutylamides previously isolated from plant materials. A trace of the active material, when placed on the tongue, produces an intense burning, paralytic effect on the tongue and on the mucous membranes of the lips and mouth. Herculin has approximately the same order of paralyzing action and toxicity to house flies as the pyrethrins.

Sapindaceae (Soapberry Family). Sapindus marginatus. This tree, up to 3o feet high, is native in Florida. It is planted occasionally for interest or ornament. The word sapindus comes from the Latin for soap, combined with Indian, in allusion to the Indians' use of the berries for soap; the pulp lathers easily like soap. S. L. Hoover obtained a patent for the use of the berries of the tree as an insecticide or insectifuge. Three berries protected a bushel of wheat against infestation. In powdered or liquid form and mixed with dried foodstuffs, it repelled weevils and other insects.

Simarubaceae (Ailanthus or Quassia Family). This tree stands smoke and city conditions well, but the male flowers have a strong odor, which is offensive to some persons. The bark and wood contain insecticidal principles, which are used on only a few crops.

Solanaceae (Nightshade or Potato Family). The potato family, often called the tobacco or tomato family, includes vegetables of world-wide cultivation, narcotics, drugs, tobacco, and a large number of garden flowers. Duboisia hopwoodii, called pituri, is an Australian species and often is mentioned in discussions of nicotine. C. V. Bowen, a chemist in the Department of Agriculture, analyzed the dried leaves and larger stems and found the leaves to contain 3.3 percent and the larger stems 0.5 percent of nornicotine. H. H. Smith and C. R. Smith of the Department studied 29 wild species of Nicotiana. They found that 5 species contained the alkaloid nornicotine only and 18 a mixture of nornicotine and nicotine. Against some insects, nornicotine is superior to nicotine. Nornicotine is more toxic to a nasturtium aphid and the pea aphid; about equally toxic to the cabbage aphid, the citrus red mite, and other spider mites; but less toxic to the celery leaf tier, the large milkweed bug, and larvae of codling moth.