Insect Antifeeding Substances in Plant Leaves

Insect antifeeding substances contained in plant leaves were widely surveyed by monitoring with 'leaf-disc test'. Larvae of tobacco cutworm, Spodoptera litura F., were mainly the test insects and leaves of sweet potato, Ipomoea batatas Lamark var. edulis Makino, the insect baits. Leaves of Cocculus trilobus DC, Parabenzoin trilobum Nakai (= Lindera triloba Blume), Orixa japonica Thunberg, Clerodendron tricotomum, Caryopteris divaricata Maxim and other Verbenaceae plants have been systematically examined. Many kinds of insect antifeeding substances, i.e. alkaloids, sesquiterpenes, coumarines and diterpenes, were isolated and identified. These chemical structures have contributed to the knowledge of natural products chemistry and suggested the parent structure of insect antifeeding substances. The methodology for insect antifeeding substance research is discussed.