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Broadleaf Herbicide Effects on Clethodim and Quizalofop-P Efficacy on Volunteer Wheat (Triticum aestivum)

  • Robert E. Blackshaw (a1), K. Neil Harker (a2), George W. Clayton (a2) and John T. O'Donovan (a3)


Field experiments were conducted at three locations in 2003 and 2004 to examine clethodim and quizalofop-P efficacy on spring wheat seedlings when applied alone or in tank mixtures with herbicides used to control broadleaf weeds. Clethodim at the recommended rate of 30 g/ha reduced spring wheat biomass by 63 to 98% and was only >90% in three of six site years. In contrast, quizalofop-P at the recommended rate of 36 g/ha reduced wheat biomass >90% in all cases. Clethodim or quizalofop-P could be tank mixed with 2,4-D ester, bromoxynil, or bromoxynil plus MCPA ester with little risk of reduced efficacy on wheat. However, 2,4-D amine was highly antagonistic to both herbicides. The commercial mixture of thifensulfuron plus tribenuron reduced clethodim, but not quizalofop-P, efficacy on wheat. Herbicide options exist for simultaneous control of volunteer glyphosate-resistant canola and glyphosate-resistant wheat if the latter technology were to be commercialized in the future.


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Broadleaf Herbicide Effects on Clethodim and Quizalofop-P Efficacy on Volunteer Wheat (Triticum aestivum)

  • Robert E. Blackshaw (a1), K. Neil Harker (a2), George W. Clayton (a2) and John T. O'Donovan (a3)


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