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Field‐evolved resistance to four modes of action of herbicides in a single kochia ( Kochia scoparia L. Schrad.) population
Author(s) -
Varanasi Vijay K,
Godar Amar S,
Currie Randall S,
Dille Anita J,
Thompson Curtis R,
Stahlman Phillip W,
Jugulam Mithila
Publication year - 2015
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.4034
Subject(s) - acetolactate synthase , dicamba , scoparia , atrazine , weed , glyphosate , biology , population , auxin , agronomy , crop , pesticide resistance , weed control , botany , pesticide , gene , genetics , demography , sociology
BACKGROUND Evolution of multiple herbicide resistance in weeds is a serious threat to weed management in crop production. Kochia is an economically important broadleaf weed in the US Great Plains. This study aimed to confirm resistance to four sites of action of herbicides in a single kochia ( Kochia scoparia L. Schrad.) population from a crop field near Garden City ( GC ), Kansas, and further determine the underlying mechanisms of resistance. RESULTS One‐fourth of the GC plants survived the labeled rate or higher of atrazine [photosystem II ( PSII ) inhibitor], and the surviving plants had the Ser‐264 to Gly mutation in the psb A gene, the target site of atrazine. Results showed that 90% of GC plants survived the labeled rate of dicamba, a synthetic auxin. At least 87% of the plants survived up to 72 g a.i. ha −1 of chlorsulfuron [acetolactate synthase (ALS) inhibitor], and analysis of the ALS gene revealed the presence of Pro‐197 to Thr and/or Trp‐574 to Lue mutation(s). Most GC plants also survived the labeled rate of glyphosate [5‐enolpyruvylshikimate‐3‐phosphate synthase (EPSPS) inhibitor), and the resistant plants had 5–9 EPSPS gene copies (relative to the ALS gene). CONCLUSION We confirm the first case of evolution of resistance to four herbicide sites of action (PSII, ALS and EPSPS inhibitors and synthetic auxins) in a single kochia population, and target‐site‐based mechanisms confer resistance to atrazine, glyphosate and chlorsulfuron. © 2015 Society of Chemical Industry