Discovery and development of pyridalyl

To create a novel insecticide for lepidopterous pest control, we started modifications of known compounds having a dichloropropenyl moiety that were reported to be active against lepidopterous larvae. Although the lead compound showed only weak activity, some breakthroughs in modifications brought us dramatic improvements in insecticidal activity and lead to the discovery of pyridalyl. Pyridalyl is highly active against various lepidopterous larvae, thrips and dipterous leafminers. In contrast, it is less toxic to a wide range of beneficial organisms. Unique symptoms in insects exposed to pyridalyl suggest that it has a distinctive insecticidal mode of action. Pyridalyl is expected to be useful in IPM and IRM programs in crop productions.