Multichemical resistance of the coniferPodocarpus gracilior (Podocarpaceae) to insect attack

Abstract

Podocarpus gracilior is resistant in nature to insect attack. Apparently, the resistance ofP. gracilior is due to a multichemical defense mechanism. Chemicals identified as potential components of the multichemical defense are four norditerpenedilactones, including nagilactones, C, D, and F, which cause insect feeding deterrent activity ultimately coupled to an insecticidal activity, and podolide, an insecticide; two nonlethal growth-inhibiting biflavones, podocarpusflavone A and 7″,4′″-dimethylamentoflavone; and the ecdysis-inhibiting phytoecdysone, ponasterone A.