Pervasive fungicide resistance in <i>Botrytis</i> from strawberry in Norway: Identification of the grey mould pathogen and mutations

Control of grey mould, caused by Botrytis spp., is a major challenge in open field strawberry production. was isolated from plant parts collected 19 perennial fields with suspected fungicide resistance the Agder region Norway 2016. Resistance to boscalid, pyraclostrobin and fenhexamid high found 89.1%, 86.0% 65.4% conidia samples, respectively. Multiple common; 69.6% samples exhibited three or more fungicides. group S B. cinerea sensu stricto isolates were obtained 16 fields, The sdhB, cytb, erg27 mrr1 genes selection examined for presence mutations known confer pyraclostrobin, pyrimethanil plus fludioxonil, Allele-specific PCR assays developed efficient detection resistance-conferring cytb. Among isolates, 84.7%, 86.3% 61.3% had cytb erg27, A triplet deletion mrr1, resulting ?L497, commonly associated multidrug phenotype MDR1h, detected 29.2% isolates. High frequencies several fungicides also both imported domestically produced transplants. Fungicide not different among grouped level mould problem assessed growers, indicating factors other than contributed control failure, fact that has important implications future management mould.