Antifeedant Activity and Acute and Residual Toxicity of Alkaloids from <I>Sophora flavescens</I> (Leguminosae) Against Formosan Subterranean Termites (Isoptera: Rhinotermitidae)

Abstract

Ku Shen, Sophora flavescens Aiton (Leguminosae), contains alkaloids that possess broad biological activities. This study showed that total matrines (a mixture of the alkaloids), and matrine and oxymatrine (two major alkaloids) had a strong antifeedant effect against Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), at all tested concentrations (ranging from 0.01 to 5%). Total matrines and matrine also had significantly toxic effects at 5%. The estimated LD50 of total matrines and matrine was 12.3 and 8.6 microg per insect, respectively, after 24 h; 13.3 and 7.1 microg per insect after 48 h; and 10.1 and 4.8 microg per insect after 1 wk. The antifeedant and toxic properties of total matrines- and matrine-treated wood remained effective at least 12 mo after treatment under both light and dark storage conditions. These chemicals have great potential for commercial development as wood treatment agents.