Growth inhibitory, insecticidal, and feeding deterrent effects of (12Z,15Z)-1-acetoxy-2-hydroxy-4-oxo-heneicosa-12,15-diene, a compound from avocado fruit, to Spodoptera exigua

We isolated and identified (12Z,15Z)-1-acetoxy-2-hydroxy-4-oxo-heneicosa-12,15-diene (persin) from avocado as a compound toxic to Spodoptera exigua larvae. Persin was obtained from oil extracted from the specialized idioblast cells of avocado fruit. When tested for activity using neonates in no-choice artificial diet bioassays, persin at concentrations of 200 μg/g inhibited growth; larvae gained only ~50% of the weight attained by control insects after seven days. At concentrations of 400 μg/g or above, larval growth was reduced by >70% as measured by weight gain, and significant mortality occurred. In choice tests, persin at concentrations of 400 μg/g or higher deterred feeding, with significantly more larvae being found on control diet than on persin-treated diet. Possible applications of persin as a natural insecticide are discussed.