NEW INSECTICIDES WITH ECDYSTEROIDAL AND JUVENILE-HORMONE ACTIVITY

Agrochemical research over the last two decades has resulted in the di scovery of chemically novel insecticides that mimic the action of the two insect growth and developmental hormones, the steroidal 20-hydroxy ecdysone (20E) and the sesquiterpenoid juvenile hormone (JH). Bisacylh ydrazines are non-steroidal agonists of 20E and exhibit their insectic idal activity via interaction with the ecdysteroid receptor proteins. Interestingly, two of the bisacylhydrazine (tebufenozide and RH-2485) insecticides are very selectively toxic to lepidopteran pests. These i nsecticides are safe to beneficial insects and have a benign ecotoxico logical profile. Aromatic non-terpenoidal insecticides (fenoxycarb and pyriproxyfen) mimic the action of JHs. However, like the JHs, their e xact mode of action is not well understood. These insecticides are tox ic to a broad spectrum of insects during their embryonic, last larval, or reproductive stages. The insecticidal, ecotoxicological properties and the mode of action of the two groups of insecticides are reviewed in this article.