Antifeeding Active Substances for Insect in Caryopteris divaricata Maxim

Abstract

Six antifeeding active diterpenes having a clerodane skeleton, clerodin (I), caryoptin (II), dihydroclerodin-I (V), dihydrocaryoptin (VI), clerodin hemiacetal (VII), and caryoptin hemiacetal (VIII), were isolated from Caryopteris divaricata Maxim. Antifeeding activities of six compounds and these derivatives against the 3rd instar larvae of Spodoptera litrrra F. were tested by the leaf disk method. In addition, the terms of “relative antifeedant” and “absolute antifeedant” were proposed for the antifeeding substances, and the latter term was used to the above six diterpenes.