Novel insecticides: Modes of action and resistance mechanism

Abstract

AbstractEfforts have been made during the past three decades to develop insecticides with selective properties that act specifically on biochemical sites present in particular insect groups, but whose properties differ from other insecticides. This approach has led to the discovery of compounds that affect the hormonal regulation of molting and developmental processes in insects, e.g., ecdysone agonists (tebufenozide and methoxyfenozide), juvenile hormone mimics (pyriproxyfen and fenoxycarb), and chitin synthesis inhibitors (benzoylphenyl ureas and buprofezin). In addition, compounds that selectively interact with the insect nicotinic acetylcholine receptor such as imidacloprid, acetamiprid, and thiamethoxam have been introduced for the control of aphids, whiteflies, and other insect species.In this issue, we report on some new insecticides that fit the current approach of pest management programs, such as the new non‐steroidal ecdysone agonist THQ [1‐aroyl‐4‐(arylamino)1,2,3,4‐tetrahydroquinoline], which acts preferentially against mosquitoes with no appreciable effect on other insect groups or mammals. The mode of action of this compound, along with its selectivity, is discussed in detail in the report of Palli et al. Another novel compound reported in this issue is pyradalyl (S‐1812), which was found to act selectively on lepidopterans and thrips. In laboratory assays, pyradalyl was found to act on insect cell lines with no appreciable effect on mammal cell lines. The potential use of this compound in agricultural systems is discussed by Isayama et al.Three reports in this issue deal with resistance mechanisms and resistance management of novel insecticides. Nauen et al. present an up‐to‐date review on insect resistance mechanisms to neonicotinoids and ways to optimize their use in pest management programs. Horowitz et al. report on Bemisia tabaci biotypes B and Q and their resistance to neonicotinoids and pyriproxyfen. One of the most striking findings in their report is that the Q biotype develops resistance to pyriproxyfen and neoicotinopid faster than biotype B, while the latter exhibits better fitness. The practical implications of these findings are discussed. In another report, Ishaaya et al. present a study detailing the toxicity and cross‐resistance of selected biorational insecticides. Their findings indicate that no appreciable cross‐resistance was observed between the benzoylphenyl urea, novaluron, the juvenile hormone mimic, pyriproxyfen, and the neonicotinoids, acetamiprid and imidacloprid. Hence, these compounds could be used, in alternation, as components in insecticide resistance management programs.