Pyridalyl: A Novel Compound with Excellent Insecticidal Activity, High Selectivity, and Unique Mode of Action

Pyridalyl is a novel synthetic insecticide discovered by Sumitomo Chemical Co. Ltd. and has been developed globally as the trade names, Pleo, or Sumipleo. The compound is highly effective against various pests of Lepidoptera, Thysanoptera, Diptera and certain Acari, including resistant strains that are less susceptible or resistant to existing insecticides. The lepidopterous larvae treated with pyridalyl exhibited unique symptoms that were not observed with existing insecticides, suggesting the novel mode of action of pyridalyl. Intoxication study found that pyridalyl has a wide range of effective dosage, and thus the compound can provide an excellent anti-feeding activity against target insect pests. The laboratory and field experiments found that pyridalyl has an excellent selectivity between target insect pests and beneficial arthropods including pollinators, predators and parasitoids. In the cytotoxicological experiments using an insect cell line Sf9, the cytotoxicity of pyridalyl and its analogs on Sf9 cells were highly associated with the insecticidal activity against S. litura, indicating that the cytotoxicity of pyridalyl in Sf9 cells reflects its insecticidal action at least in part. The cytotoxicity study also found that pyridalyl displayed obvious cytotoxicity to Sf9 cells whereas it had no effect on a mammalian cell line CHO-K1, thereby high selectivity was observed even at cell-line level. These characteristics of pyridalyl would allow the compound to be one of the most powerful tools for controlling and managing pest insects under IPMand IRM-based crop protection programs. _____________________________________________________________________________________________________________