Antifungal activities of sunflower terpenoids

Five terpenoids, two sesquiterpene lactones and three diterpene acids, isolated from cultivated sunflower, were examined for their effects on the growth of two economically important pathogens of sunflower and other crops. The minimum inhibitory concentrations of the terpenoids tested ranged from 10 to 100 ppm for Verticillium dahliae and 10 to 1000 ppm for Sclerotinium sclerotiorum. A mixture of two diterpene acids, kaurenoic and angeloylgrandifloric, was the most potent inhibitor of hyphal growth. Selective breeding to increase the amounts of these terpenoids in sunflower could improve the natural resistance in fungal pathogens.