The insecticidal activity of foliage from New Zealand conifers

When incorporated into artificial diets, the milled foliages of many New Zealand conifers are toxic to larvae of housefly (Musca domestica), codling moth (Laspeyresia pomonella) and light-brown apple moth (Epiphyas postvittana). The most toxic foliages are those of Podocarpus nivalis which contains diterpene lactones, and Dacrydium laxifolium, which has a high concentration (1%) of phytoecdysones. The insecticidal activities of the plants are discussed in relation to their insect associations, chemistry and taxonomy.