ABSTRACT
A limited number of postemergence (POST) herbicides
are available for weed management in azuki
bean production in Ontario. A total of three field trials were conducted during 2017 to 2019 at the Huron Research
Station, University of Guelph, Exeter, Ontario, Canada to evaluate the efficacy of various postemergence (POST) herbicides for
weed control in azuki bean. Fomesafen, acifluorfen and acifluorfen + Assist® caused up to 6% crop injury and weed interference reduced azuki bean yield up
to 42%. Bentazon, bentazon Forte, bentazon/acifluorfen, bentazon + fomesafen + Assist®, bentazon + fomesafen + Turbocharge® and bentazon Forte + fomesafen caused up to 16% injury and weed interference reduced azuki bean yield up to
53%. Fomesafen, acifluorfen, acifluorfen + Assist®, bentazon, bentazon Forte, bentazon/acifluorfen, bentazon + fomesafen + Assist®, bentazon + fomesafen +
Turbocharge® and bentazon Forte + fomesafen provided 36% to 88% control of
redroot pigweed (Amaranthus retroflexus L.), common ragweed (Ambrosia artemesiifolia L.), and common lambsquarters (Chenopodium album L.). Fomesafen, acifluorfen + Assist® and acifluorfen provided 59% to 83% control of flower-of-an-hour
(Hibiscus trionum L.), but bentazon, bentazon Forte, bentazon/acifluorfen, bentazon + fomesafen + Assist®, bentazon + fomesafen +
Turbocharge® and bentazon Forte + fomesafen provided 78% to 99% control of H. trionum. All POST herbicides evaluated provide 99% to 100% control of wild
mustard (Sinapis arvensis L.) in
azuki bean. Based on these results, none of the POST herbicide
evaluated that included bentazon can
be used safely for the control of annual broadleaved weeds in azuki bean under
Ontario environmental conditions.