SUMMARYBenomyl‐tolerant strains of Botrytis cinerea Pers. ex Pers. were obtained from all of the 17 commercial glasshouse tomato crops sampled in Lancashire in 1977, although benzimidazole fungicides had not been used on some nurseries for up to three years. Tolerant strains were found in 64.3 per cent of lesions sampled, although in some lesions sensitive strains were also present. In a detailed study of crops growing in the same glasshouses at two sites in 1976, 1977 and 1978, there was only a small change in the number of tolerant isolates collected, although benzimidazole fungicides had not been applied since 1974.