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Response of imidazolinone‐tolerant and ‐susceptible volunteer oilseed rape ( Brassica napus L.) to ALS inhibitors and alternative herbicides
Author(s) -
Krato Christoph,
Hartung Karin,
Petersen Jan
Publication year - 2012
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.3317
Subject(s) - brassica , biology , volunteer , agronomy , acetolactate synthase , bioassay , canola , herbicide resistance , weed control , gene , biochemistry , genetics
BACKGROUND: Imidazolinone‐tolerant oilseed rape ( Brassica napus L.) varieties are currently grown in Canada, North America, Chile and Australia with high acreage. A Europe‐wide introduction has started and will be pushed further for both spring and winter varieties. The primary aim of this study was to evaluate the impact of imidazolinone tolerance for future volunteer oilseed rape control in subsequent crops, particularly winter wheat. RESULTS: A greenhouse bioassay showed cross‐tolerance of imidazolinone‐tolerant oilseed rape towards sulfonylureas, triazolopyrimidines and sulfonylaminocarbonyltriazolinones (resistance factors between 5 and 775), with a homozygous variety expressing a much higher tolerance level compared with a heterozygous variety. Calculated ED 90 values suitable for controlling tolerant plants were always much higher than the recommended herbicide dose. Generally, results were confirmed under field conditions, but with higher efficacies than expected in some cases (e.g. florasulam). Herbicides with an alternative mode of action were found to be effective in controlling imidazolinone‐tolerant volunteers in subsequent winter wheat crops. CONCLUSION: Herbicide strategies have to be adjusted for volunteer control in subsequent crops if imidazolinone‐tolerant oilseed rape varieties are to be grown. However, agronomic tools (harvest date, harvest technique, tillage) should be used conscientiously in the first place to keep volunteer oilseed rape densities at the lowest possible level. Copyright © 2012 Society of Chemical Industry