Discrimination of leaf diseases affecting faba bean (Vicia faba).

Faba bean is susceptible to several leaf diseases caused by pathogenic fungi. With the increasing importance of faba bean in northern European cropping systems, the importance of its leaf diseases is likely to increase. The aim of this study was to discriminate the diseases and to test agronomic strategies for limiting their spread in a five-year experiment. Chocolate spot disease caused by Botrytis spp. and leaf blotches caused by an Alternaria/Stemphylium complex dominated, the severity of rust was lower, and downy mildew occurred in only one year. The severity of the diseases depended on weather conditions and cultivar, but not on sowing rate. Application of fungicides significantly decreased the severity of chocolate spot, leaf blotch and rust, but not downy mildew, and in no case was the disease progress stopped. None of the cultivars showed strong resistance to disease. The Alternaria/Stemphylium leaf blotch is an emerging disease of faba bean in northern Europe. Work continues on the identification of the responsible species in the chocolate spot and leaf blotch complexes and the determination of their relative importance in causing disease. [ABSTRACT FROM AUTHOR]