Abstract Sorgoleone, a root exudate of sorghum [(Sorghum bicolor (L.) Moench] and hairy root extract of tartary buckwheat (Fagopyrum tataricum Gaertn.) were mixed and applied to different broadleaf and grass weed species and crop species in the greenhouse arranging a randomized complete block design with four replications to evaluate their combined herbicidal activity and crop selectivity. A mixture of these two natural products (sorgoleone and root extract of tartary buckwheat) showed significantly greater inhibitory effects than either one alone. Broadleaf weed species were more susceptible to the application of the mixture than grass weed species. Galium spurium, Rumex japonicus, Aeschynomene indica, and Amaranthus retroflexus were the most susceptible among the broadleaf species and Setaria viridis was the most susceptible among the grass species. Broadleaf weed species demonstrated more growth suppression than grass weed species. For example, growth of G. spurium was reduced by 80.9% at 150 µg ml -1 of sorgoleone alone and by 33.7% at 7.5 mg ml -1 of hairy root extract alone; however their mixture reduced G. spurium growth by 100%. Moreover, the mixture reduced studied crop growth slightly more than sorgoleone or hairy root extract used individually. The ability of weed growth suppression using sorgoleone and hairy root extract of tartary buckwheat together offers interesting possibilities for effective weed management
