Phytopathogenic species of fungi and fungal-like organisms identified in plant samples delivered to the Plant Disease Clinic in 2018–2020

One of the conditions for effective management of farm is an access to quick diagnostics of plant pathogens in order to reduce the occurrence of plant diseases. The Plant Diseases Clinic receives samples of infected plants supplied by growers and gardeners from all over Poland. In the years 2018–2020, a total of 274 samples were tested at the Clinic for the presence of fungi and fungal-like organisms pathogenic for plants. The tests were carried out using the microscopic method, and in case of doubt, the result was confirmed by molecular tests. The most frequently studied plant was tomato (26%), followed by strawberry (9%), cucumber (5%) and tobacco, sugar beet, onion, blueberry, raspberry, lettuce, cauliflower and potato. Conifers were also a large group, such as: thujas, cypresses and pines; a total of 17 host plants. Single species of ornamental plants were very numerous, e.g. gerbera, anthurium, aster, geranium, phlox, chrysanthemum and others. The fungi of the genus Fusarium spp. constituted about 38% of infections. This was followed by Alternaria spp. (26%), Botrytis cinerea (11%) and Cladosporium sp. (10%). The remaining diseases were caused by Pythium sp., Rhizoctonia sp., Colletotrichum sp., Ulocladium sp., Pestalotia sp. and Phytophthora sp. In recent years, the greatest threat to tomatoes and strawberries has been the fungi of the Fusarium genus, and the pathogens of the Pythium genus to cucumbers.