High frequency of fungicide resistance‐associated mutations in the wheat yellow rust pathogen <i>Puccinia striiformis</i> f. sp. <i>tritici</i>

BACKGROUND Reliance on fungicides to manage disease creates selection pressure for the evolution of resistance in fungal and oomycete pathogens. Rust fungi (Pucciniales) are major pathogens cereals other crops have been classified as low-risk developing fungicides; no case field failure a cereal rust has yet recorded. Recently, Asian soybean pathogen, Phakopsora pachyrhizi evolved several fungicide classes, prompting us screen large sample globally widespread wheat yellow Puccinia striiformis f. sp. tritici (Pst), mutations associated with resistance. RESULTS We evaluated 363 Pst isolates from Europe, USA, Ethiopia, Chile, China New Zealand target genes demethylase inhibitor (DMI; Cyp51) succinate dehydrogenase (SDHI; SdhB, SdhC SdhD) fungicides. A high proportion carrying Y134F DMI resistance-associated substitution Cyp51 gene was found among those Zealand. set geographically diverse also display (I85V) that is homologous reported recently P. linked SDHI CONCLUSION The identification alleles confirms rusts not immune operating at levels certain locations. It highlights need adopt management practices monitor species development © 2021 Authors. Pest Management Science published by John Wiley & Sons Ltd behalf Society Chemical Industry.