Rotenone

Rotenone is an odorless, colorless, crystalline isoflavone used as a broad-spectrum insecticide, piscicide, and pesticide. It occurs naturally in the seeds and stems of several plants, such as the jicama vine plant, and the roots of several members of Fabaceae. It was the first described member of the family of chemical compounds known as rotenoids. Rotenone is an odorless, colorless, crystalline isoflavone used as a broad-spectrum insecticide, piscicide, and pesticide. It occurs naturally in the seeds and stems of several plants, such as the jicama vine plant, and the roots of several members of Fabaceae. It was the first described member of the family of chemical compounds known as rotenoids. The earliest record of the now-known rotenone-containing plants used for killing leaf-eating caterpillars was in 1848, and for centuries, the same plants were used to poison fish. The active chemical component was first isolated in 1895 by a French botanist, Emmanuel Geoffroy, who called it nicouline, from a specimen of Robinia nicou, now called Lonchocarpus nicou, while traveling in French Guiana. He wrote about this research in his thesis, published posthumously in 1895 after his death from a parasitic disease. In 1902 Japanese chemist Nagai Nagayoshi isolated a pure crystalline compound from Derris elliptica which he called rotenone, after the Japanese name of the plant, roten. By 1930, nicouline and rotenone were established to be chemically the same. Rotenone is used as a pesticide, insecticide, and as a nonselective piscicide (fish killer). It is commercialized as cubé, tuba, or derris, in single preparation or in synergistic combination with other insecticides. In the United States and Canada, all uses of rotenone except as a piscicide are being phased out. Rotenone has historically been used by indigenous peoples to catch fish. Typically, rotenone-containing plants in the Fabaceae family of legumes are crushed and introduced into a body of water, and as rotenone interferes with cellular respiration, the affected fish rise to the surface in an attempt to gulp air, where they are more easily caught. Rotenone has been used by government agencies to kill fish in rivers and lakes in the United States since 1952. Small-scale sampling with rotenone is used by fish researchers studying the biodiversity of marine fishes to collect cryptic, or hidden, fishes, which represent an important component of shoreline fish communities. Rotenone is the most effective tool available because only small quantities are necessary. It has only minor and transient environmental side effects. Rotenone is also used in powdered form to treat scabies and head lice on humans, and parasitic mites on chickens, livestock, and pet animals. Rotenone has been used as an organic pesticide dust for gardens. Unselective in action, it kills potato beetles, cucumber beetles, flea beetles, cabbage worms, raspberry beetles, and asparagus beetles, as well as most other arthropods. It biodegrades rapidly in soil, with 90% degraded after 1–3 months at 20 °C (68 °F) and three times faster at 30 °C (86 °F). A light dusting on the leaves of plants will control insects for several days.