The field behaviour of seed‐borne <i>Ascochyta fabae</i> and disease control in field beans

Abstract

SUMMARY In field sowings at Cambridge 2–15% of field bean seeds carrying Ascochyta fabae produced seedlings with leaf lesions. The fungus spread for distances up to 10 m in an average season and usually infected the new crop of seed. The amount of such infection arising from a single lot varied widely when samples were grown at different centres, presumably because of differences in local weather conditions. Seed lots with approximately 1% infected seeds seem suitable for ware crop production but little or no A. fabae can be tolerated in seed intended for multiplication. Infection in British‐grown commercial seed has been greatly reduced by the selection of clean seed. Health standards adopted in the Field Bean Seed Scheme may have eliminated A. fabae from one cultivar.