Pyridachlometyl has a novel anti‐tubulin mode of action which could be useful in anti‐resistance management

BACKGROUND: Fungicide resistance is a growing problem affecting many crop pathogens owing to the low success rate in finding novel chemical classes of fungicides. Pyridachlometyl is a new fungicide that seems to belong to a new chemical class of tubulin polymerization promoters. RESULTS: Pyridachlometyl exhibited potent antifungal activity against a broad range of fungal species belonging to the phyla Ascomycota and Basidiomycota. No cross‐resistance was observed with other fungicide classes, such as ergosterol biosynthesis inhibitors, respiratory inhibitors, or tubulin polymerization inhibitors in Zymoseptoria tritici. Pyridachlometyl‐resistant strains were obtainable by UV mutagenesis in Z. tritici and Penicillium digitatum. Mutations in tubulin‐coding genes were found in all laboratory mutants but the patterns of mutation were distinct from that of tubulin polymerization inhibitors, such as benzimidazole fungicides. CONCLUSION: Pyridachlometyl is a promising new tool for disease control. However, strict resistance management strategies should be recommended for the practical use of pyridachlometyl. © 2019 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.