Bipolaris sorokiniana on barley seed in Finland.
B. sorokiniana (Cochliobolus sativus) is common in commercially grown barley seed in Finland and possibly of economic importance. In 1974 the fungus was present in 60% of 200 seed samples surveyed, and in the 3 following years incidence was 19, 29 and 38%. The mean percentage of seeds infected was 3.8, 1.3, 1.2 and 1.9 respectively, and the highest individual percentage 92. In each year Paavo was the most severely infected cultivar. In most cases only the seed coat was invaded but internal infection also occurred. Severely infected seeds did not germinate, or seedlings rapidly became infected. The pathogen was less frequent in western Finland. Field tests (1972-79) confirmed the same varietal susceptibility as in the seed survey. High rainfall and RH in July and Aug. increased the incidence of seed infection.