Abstract:

Alkaloids from Sophora alopecuroids was bioassayed with Clostera anastomosis for their antifeedant and growth inhibitory effects. The antifeedant rate in choice test reached 62%～86% at the dose 2.5 mg·mL^-1, while in non-choice bioassay only 20%～29%. In choice bioassay, the antifeedant rate increased with larval instars of C. anastomosis and did not in non-choice experiment. The alkaloids also impose great influence on the growth of C. anastomosis larvae I.e. after feeding on the alkaloid treated leaves, the larvae had a big reduction on body weight, weight gain, and relative growth rate (RGR) comparing with the controls. In the second day of treatment with the dose 10 mg·mL^-1 alkaloid, the RGR reduced 39.8%, and the food intake and the feces weight is only 57.7% and 57.4% of the controls, respectively. The approximate digestibility (AD) increased significantly, and the efficiency of conversion of digested food (ECD), the efficiency of ingested food (ECI) decreased greatly after feeding treated leaves. Further, the eggs laid per female was also inhibited by this alkaloid. The significance and prospect of the alkaloids in controlling forest insect pests were also discussed.

Key words: alkaloids, Sophora alopecuroids, Clostera anastomosis, antifeedant effect, growth, food utilization rate