Phytoalexin Induction by Some Agricutural Fungicides and Phytotoxic Metabolites of Pathogenic Fungi

The endocarp of the fresh pea pod incubated with solution or suspension of agricultural fungicides, phytotoxic metabolites of plant pathogenic fungi formed the pea phytoalexin, pisatin. Among the compounds tested, cycloheximide, triazine, dichlone, phenyimercury acetate, UV degradation product of phenylmercury acetate, triphenyltin fungicides, and 3-hydroxy-5-methylisoxazole induced pisatin. Ophiobolin, a toxin from Cochliobolus mtyabeanus, and ascochitine, a toxic metabolite from Ascochyta fabae, also induced pisatin. The possibilities of the development of harmless plant disease control agents was discussed in relation- to the induced synthesis of phytoalexins.