Insect-Control Chemicals from Plants. Nagilactone C, A Toxic Substance from the Leaves of Podocarpus Nivalis and P. Hallii

Feeding tests showed that the powdered dried leaves and leaf extract of P. nivalis Hook and P. hallii Kirk are toxic to housefly larvae when incorporated into a milk diet. An active toxic ingredient has been isolated and identified as the known norditerpene lactone, nagilactone C. Nagilactone Cat 50 p.p.m. in a defined medium was toxic to housefly larvae. At lower concentrations it inhibited larval growth, maturation to pupae, and emergence of adults. Nagilactone C was not toxic to 3-4-day·old housefly larvae or to 2-3 day old adults when applied topically at the rate of 5 p.g per insect.