Bipolaris sorokiniana on barley seed in Finland

Authors

• Aarne Kurppa Department of Plant Pathology, University of Helsinki, SF-00710 HELSINKI 71, Finland

DOI: https://doi.org/10.23986/afsci.72169

Abstract

Bipolaris sorokiniana is reported as a common fungus in commercially grown barley seed in Finland with possible economic importance. In 1974, when 200 samples of barley seed were surveyed the fungus was identified in 60 per cent of samples. The three following years the incidence was 19, 29 and 38 %. The mean per cent seeds infected was 3.8, 1.3, 1.2 and 1.9 respectively. The highest recorded individual % was 92. The most severely infected cultivar was Paavo each year. In most cases only the seed cover was invaded by the fungus but also infection in the embryo and the cell leyers surrounding it was observed. Such severely infected seeds did not germinate or the seedlings were readily infected after germination. B. sorokiniana was less frequent in the western parts of the country. Field experiments in 1972—1979 confirmed the same varietal susceptibility which was found by the survey of commercial samples of barley seed. High rainfall and relative humidity in July and August were the main factors associated with increased seed infection incidence.