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.