Recently, a new fungal disease caused by Diaporthe angelicae (anamorph Phomopsis foeniculi) has been found with increasingly frequency on fennel (Foeniculum vulgare) in Bulgaria. Using a bioassay-guided isolation and purification procedure, different metabolites were isolated from the fungal culture filtrates. They were identified by spectroscopic methods as nectriapyrone, a pentaketide monoterpenoid, and altersolanols A and J and macrosporin, three octaketides anthracenones. Leaf puncture bioassay was applied on detached tomato leaves to prove the phytotoxic activity of the fractions and of pure compounds. Nectriapyrone and altersolanols A and J showed a modulated phytotoxicity, while macrosporin was not toxic. Altersolanol A was the most active compound

Some physiological aspects of interactions between wheat and Zymoseptoria tritici were studied by measuring changes in some stress markers, photosynthetic activity, and the extent of thermal energy dissipation. Four winter wheat genotypes varying in their level of resistance, determined on the basis of necrotic leaf area and presence of pycnidia, were inoculated at a seedling stage and measurements were performed at 0, 2, 17, and 23 d after the inoculation. Physiological activity of wheat genotypes showed that keeping the membrane integrity and the extent of oxidative stress is of significant importance for pathogen resistance. It could be suggested that the changes in electrolyte leakage, malondialdehyde content, and values of quantum yield of PSII electron transport and nonphotochemical fluorescence quenching can be used to screen the degree of tolerance to Septoria tritici blotch in different wheat genotypes.

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