Antifeedant and Insecticidal Activity of Quassinoids against Diamondback Moth (Plutella xylostella)

The antifeedant and insecticidal activities of sixteen quassinoids against 3rd instar larvae of the diamondback moth (Plutella xylostella) were compared with those of known insect antifeedant chlordimeform (1), and the structure-activity relationship was discussed. The insecticidal activity of quassin (2) was higher than that of 1, although its antifeedant activity was nearly the same as that of the reference compound.