The health status of hawthorns growing in different greenery areas of Poznań was evaluated in 2008–2009. In 2008 rust symptoms caused by Gymnosporangium confusum were observed on both Crataegus monogyna and C. oxyacantha, but in the next year the rust did not occur. In 2009 the powdery mildew caused by Phyllactinia corylea on the lower side of leaves of C. monogyna as well as Entomosporium leaf spot on C. oxyacantha were found. The leaf spot was caused by the fungus Entomosporium maculatum (syn. E. mespili) which has the perfect stage Fabraea maculata (syn. Diplocarpon maculatum). The first symptoms of this disease were small (1–2 mm diameter), brownish spots on the upper side of leaves in the early summer. Rainy weather in May, June and July of 2009 stimulated the development and spread of Entomosporium leaf spot. The defoliation was due to this disease. Conidia of E. maculatum are very characteristic, resembling minute insects.
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