Antifeedants against Acusta despesta from the Japanese cedar, Cryptomeria japonica.

During our studies on the components in Japanese cedar, Cryptomeria japonica, we found that the crude methanol extract of C. japonica showed intense antifeeding activity against one snail species, Acusta despesta, which is well-known as a pest of many vegetables and crops. The active components in the extract were separated into the hexane and ethyl acetate soluble fractions. From the active ethyl acetate soluble fraction, two norlignans, sequirin-C and agatharesinol, were isolated and identified as the active compounds. Both compounds inhibited feeding behavior of A. despesta at 30 microg/cm2 and 40 microg/cm2 concentrations, respectively, when applied by an eggplant leaf or filter paper containing 20 microl of 5% sucrose solution.