EFFECTS OF NEOCLERODANE DITERPENES FROM TEUCRIUM ON FEEDING-BEHAVIOR OF COLORADO POTATO BEETLE LARVAE

Treatment of potato leaf disks with four neo-clerodane diterpenes from Teucrium (eriocephalin, teucrin-A, teucvin, and teuscorolide) signifi cantly reduced feeding by larvae of Leptinotarsa decemlineata (Colorad o potato beetle). Choice and no-choice tests suggest that teuscorolide acts as a feeding deterrent, whereas the antifeedant activity of teuc rin-A, teucvin, and eriocephalin is likely associated with a toxic mod e of action. Nutritional tests, antifeedant simulation assays, and pos ttreatment studies confirmed that teucrin-A can be categorized by its mode of action as a toxin, rather than as a feeding deterrent.