Occurrence and viability of Septoria oenotherae in commercial seed samples of evening primrose

Pycnidia of Septoria oenotherae were detected in 146 out of 198 commercial seed stocks examined. Where present, pycnidia were usually on fragments of pods, stems or leaves contained in these stocks, and were only rarely on the seeds. Of 124 samples tested, 61 samples produced viable conidia as demonstrated by inoculating test seedlings. Spring and winter crops from the UK and New Zealand, and spring crops from The Netherlands, frequently produced seed stocks containing pycnidia and viable conidia on non-seed debris that caused Septoria disease symptoms in test seedlings. Conidia capable of infecting test plants were detected after 5 years in stored seed samples and after 10 months in soilborne debris of evening primrose.