GROWTH-INHIBITORY, INSECTICIDAL, AND FEEDING DETERRENT EFFECTS OF )-1-ACETOXY-2-HYDROXY-4-OXO-HENEICOSA-12,15-DIENE, A COMPOUND FROM AVOCADO FRUIT, TO SPODOPTERA-EXIGUA

We isolated and identified 5Z)-1-acetoxy-2-hydroxy-4-oxoheneicosa-12,1 5-diene (persin) from avocado as a compound toxic to Spodoptera exigua larvae. Persin was obtained from oil extracted from the specialized i dioblast cells of avocado fruit. When tested for activity using neonat es in no-choice artificial diet bioassays, persin at concentrations of 200 mu g/g inhibited growth; larvae gained only similar to 50% of the weight attained by control insects after seven days. At concentration s of 400 mu g/g or above, larval growth was reduced by > 70% as measur ed by weight gain, and significant mortality occurred. In choice tests , persin at concentrations of 400 mu g/g or higher deterred feeding, w ith significantly more larvae being found on control diet than on pers in-treated diet. Possible applications of persin as a natural insectic ide are discussed.