Abstract: An object of the present invention is to provide a method for screening elicitors that induce the production of phytoalexins in rice plants, and agents for controlling rice diseases; and relates to a method for screening elicitors that induce the production of phytoalexins in rice plants, wherein the aforementioned elicitor screening method is characterized by using rice seedlings as the test plant, applying a test sample on a suitable part of the rice seedlings, and then screening the elicitors using the phytoalexins produced in the plant bodies as marker substances, as well as to agents for controlling rice diseases containing as an active ingredient a specific compound having an action in inducing the production of phytoalexins in rice plants.

Abstract: The present invention relates to phytocassanes which are novel diterpene compounds exhibiting an antifungal activity against rice blast fungus, Pyricularia oryzae (Magnaporthe grisea) and rice sheath blight fungus, Rhizoctonia solani, and more specifically, it relates to phytocassanes A, B, C, D, and EL and a process for producing phytocassanes or momilactones, antifungal diterpene compounds, at a high yield.