Chocolate spot of field beaes in Scotland

SUMMARY Although Botrytis fabae Sard, was frequently isolated from spring‐sown Scottish field bean crops in 1976–80, chocolate spot is not regarded as such a serious problem in Scotland as it is in England and Wales, where a large proportion of the crop is autumn‐sown. Pieces of leaf (with lesions) from bean crops grown on two farms at different sites in Scotland were plated on agar during the five seasons 1976–80. The calculated date on which B. fabae was recovered from 50 per cent of the pieces each year was consistently earher on one farm than on the other, despite apparently similar climates. There was a highly significant correlation (coefficient of 0.90) between the severity of chocolate spot disease in different regions of England and Wales and temperatures during May. This, however, may merely reflect regional differences in the proportions of autumn‐ and spring‐sown crops.