The response of some spring barley cultivars grown in Finland to air-borne secondary infection by Bipolaris sorokiniana

Authors

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

DOI: https://doi.org/10.23986/afsci.72190

Abstract

Air-borne secondary inoculum of Bipolaris sorokiniana caused severe foliar diseases and yield losses in all 12 spring barley cultivars tested in greenhouses or in the field. For secondary infection to occur a high relative humidity was necessary. Yield losses due to foliar diseases reached a maximum of 43.4 % in greenhouse experiments and 27.8 % in the field. The mean losses were 20.3 % and 12.3%, respectively. Early infection at the time of heading or shortly after it resulted in higher yield losses than did later infection, although the symptom expression was opposite. Spore inoculation or natural secondary infection by the spores from a diseased crop after heading always resulted in a high infection incidence in the grain. Infection incidence as well as fungal invasion of the internal cell leyers of the grains varied significantly among barley cultivars. The most susceptible of those tested were cvs. Teemu, Paavo and Pomo, while the most resistant were Ingrid, Otra and Pirkka.