LEAF SPOTS at first pale green, later grey-green, finally pale brown, subcircular to prolate, 0.8 to 1.2 mm diam, with a narrow, brown margin.
PYCNIDIA (p) crowded on the lesions, immersed or slightly erumpent, subepidermal, unilocular, globose to subglobose, sometimes slightly flattened, 55-100 µm diam, yellow to dark brown, with a subcircular to elliptical ostiolum, 20-40 µm diam.
Wall (w) 3-5 µm thick, composed of thick-walled, yellow to brown, angular cells.Conidiogenous cells (cc) phialidic, hyaline, sessile on the inner surface of the pycnidial wall.
CONIDIA (c) hyaline, filiform or slightly cylindrical, usually slightly curved, euseptate or with a few thin septa, 27-40 x 1-1.4 µm.
PLANT HOST AND DISTRIBUTION. The plant hosts of S. petroselini are members of the genera Conioselinum and Petroselinum (Farr et al. 1989).
This fungus occurs in the temperate northern hemisphere (Farr et al. 1989). According to Smith et al. (1988), S. petroselini is very common on P. crispum in Europe.
NOTES. Septoria petroselini causes a leaf spot of Petroselinum crispum (Mill.) A.W. Hill. (Ellis and Ellis 1987). According to Madej (1974), the economical harmfulness of this fungus is rather low in north-western Poland.
Septoria petroselini also form pycnidia on seeds. Conidia from these pycnidia attack the seedlings.
The weather conditions favourable to germination of conidia and their dissemination ar 18-24oC, as well as rainy and windy days.
The conidia of S. petroselini penetrate into leaves of its plant host through the cuticule, rarely through stomata.
Septoria petroselini overwinters in seeds and plant debris.
Septoria petroselini significantly affects the quality of marketed parsley (Smith et al. 1988).
Septoria petroselini is very similar to S. apiicola Speg., but does not attack celery (Smith et al. 1988).
Ellis M. B., Ellis J. P. 1987. Microfungi on land plants. An identification handbook. Croom Helm. London and Sydney.
Farr D. F., Bills G. F., Chamuris G. P., Rossman A. Y. 1989. Fungi on plants and plant products in the United States. APS Press. The American Phytopathological Society. St. Paul, Minnesota. USA.
Madej T. 1974. Materialy do mikoflory roslin woj. szczecinskiego. Rozprawy nr 35. Akad. Roln. Szczecin.
Smith I. M., Dunez J., Lelliott R. A., Phillips D. H., Archer S. A. 1988. European handbook of plant diseases. Blackwell Scientific Publications.