Abstract Metyltetraprole is a novel quinone outside inhibitor (QoI) fungicide designed to avoid cross-resistance in cytochrome b G143A-harboring QoI-resistant phytopathogenic fungi. The resistance factors of fungal isolates for metyltetraprole are around 1, but > 200 the reference QoI azoxystrobin. In this study activities against azoxystrobin-resistant carrying G137R, G137S, L299F, N256S + ...