Nematotoxicity of spp. Extracts and Tea Seed Cake and Extracts to and .

Tea-oil camellia () is grown for tea seed oil production, with tea seed cake produced as a byproduct. Rather than disposing of the cake, agricultural uses increase the value of oil production. Constituents of are also utilized for traditional Chinese medicine, as are compounds produced by tree peony roots. Consequently, the unused cake, and stems from two tree peony species, and , were studied for compounds antagonistic to soybean cyst nematode () and root-knot nematode (). Extracts from cake and stems suppressed hatch and were nematotoxic to second-stage juveniles (J2) of both nematode species. extracts were more effective than . extracts for decreasing hatch and J2 viability. In greenhouse trials with soybean ( 'Essex'), powdered cake applied as a soil amendment suppressed cysts/g root by up to 66% compared with nonamended controls. These results indicate that the extracts and cake contain compounds active against and , with activity varying between the two species. tea seed cake, and constituents of the cake or of , are candidates for further studies on management of these nematodes.