Many plants contain chemicals that are toxic to insects.
Some of these have been known about for a long time and a few have been commercially developed and processed into an insecticide product used for pest control. Because these naturally occurring insecticides are derived from plants, they are called botanical insecticides or botanicals. The best known, and most widely used botanical insecticide is pyrethrum, a mixture of different insecticidal compounds found in the dried flower head of the pyrethrum daisy, Chrysanthemum cinerariaefolium . Other botanicals include rotenone, extracted from the roots of Derris and Lochocarpus plants, sabadilla, derived from ripe seeds of a tropical lily called Schoenocaulon officinale, ryania which comes from the woody stems of the Ryania speciosa shrub, the formerly-popular insecticide nicotine extracted from tobacco and limonene and linalool, compounds refined from citrus oils extracted from orange and other citrus fruit peels. The newest commercial botanical is Neem, an insecticide also known by the active ingredient name azadirachtin, derived from the neem tree, Azadirachtin indica.