Insecticidal and acaricidal activity of pipernonaline and piperoctadecalidine derived from dried fruits of Piper longum L.

Toxicities of two piperidine alkaloids, pipernonaline and piperoctadecalidine, isolated from Piper longum L. were determined against five species of arthropod pests. The most potent insecticidal activities of both alkaloids, pipernonaline (LD50=125 mg/l) and piperoctadecalidine (LD50=95.5 mg/l), were against Spodoptera litura F. (Lepidoptera: Noctuidae). Both alkaloids also showed insecticidal activities towards Myzus persicae Sulzer (Hemiptera: Sternorrhynche: Aphididae). Piperoctadecalidine (LD50=246 mg/l) but not pipernonaline showed acaricidal activity against Tetranychus urticae Koch (Acari: Tetranychidae). Neither compound showed insecticidal effects on Nilaparvata lugens Stål (Hemiptera: Fulgoromorpha: Delphacidae) or Plutella xylostella L. (Lepidopetera: Yponomeutoidae).