Study on Displacement Control of Flaveria bidentis Kuntze with Alfalfa and Sunflower
Flaveria bidentis Kuntze is a new invasive weed discovered in 2001 in China, and displacement control is a main approach to checking its spread. In a study reported in this paper, the effect of competition between F. bidentis and alfalfa or sunflower was investigated in the lab and in the field. The results showed that the germination of alfalfa and sunflower seeds treated with the aqueous extract of F. bidentis was not inhibited, but the germination of F. bidentis seeds was suppressed by the extract of alfalfa. F. bidentis seeds treated with alfalfa extract at 0. lg/mL gave a germination rate of 32% only. Further investigation revealed that the allelopathic substance produced by alfalfa retarded the growth of the radicle of F. bidentis while the extract of sunflower had no such effect. Branch number, plant height, biomass and plant density of F. bidentis were markedly restrained by low density alfalfa and sunflower planted in the field.